TEXAS INSTRUMENTS DAC8718 Technical data

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DAC8718

ControlLogic

An ogal Monit ro

ToDAC-0,DAC-1,

DAC-2,DAC-3

ToDAC-0,DAC-1,

DAC-2,DAC-3

ToDAC-4,DAC-5,DAC-6,DAC-7

DAC8718

OFFSET-B

AGND-B

V -7

OUT

MON

OFFSET-A

AGND-A

REF-B

Reference

BufferB

InternalTrimming

Zero/Gain;INL

Reference

BufferA

OFFSET

DACA

OFFSET

DACB

DAC-0

Latch-0

Power-Up/

Power-Down

Control

(SameFunctionBlocks

forAllChannels)

REF-A

LDAC

RST

RSTSEL

LDAC

CLR

USB/BTC

AIN-0

AIN-1

GPIO-0 GPIO-1 GPIO-2

SDO

SDI

SCLK

WAKEUP

SPIShiftRegister

IOVDDDGND DVDDAVDDAV

DGND DVDDAVDDAV

V -0

OUT

V -7

OUT

AIN-0

AIN-1 RefBufferA RefBufferB

OFFSET-B

Mux

Command

Registers

InputData Register0

Correction

Engine

(WhenCorrectionEngineDisabled)

DAC-0

Data

UserCalibration:

ZeroRegister0 GainRegsiter0

V -0

OUT

DAC8718

www.ti.com

SBAS467A –MAY 2009–REVISED DECEMBER 2009

Octal, 16-Bit, Low-Power, High-Voltage Output, Serial Input

DIGITAL-TO-ANALOG CONVERTER

Check for Samples: DAC8718

FEATURES

2345

• Bipolar Output: ±2V to ±16.5V

• Unipolar Output: 0V to +33V

• 16-Bit Resolution

• Low Power: 14.4mW/Ch (Bipolar Supply)

• Relative Accuracy: 4 LSB Max when operating from a +30.5V (or higher) power

• Low Zero/Full-Scale Error – Before User Calibration: ±10 LSB Max – After User Calibration: ±1 LSB

• Flexible System Calibration

• Low Glitch: 4nV-s

• Settling Time: 15μs

• Channel Monitor Output

• Programmable Gain: x4/x6

• Programmable Offset

• SPI™: Up to 50MHz, 1.8V/3V/5V Logic

• Schmitt Trigger Inputs

• Daisy-Chain with Sleep Mode Enhancement

• Packages: QFN-48 (7x7mm), TQFP-64 (10x10mm)

APPLICATIONS

• Automatic Test Equipment

• PLC and Industrial Process Control

• Communications

DESCRIPTION

The DAC8718 is a low-power, octal, 16-bit digital-to-analog converter (DAC). With a 5V reference, the output can either be a bipolar ±15V voltage when operating from dual ±15.5V (or higher) power supplies, or a unipolar 0V to +30V voltage

supply. With a 5.5V reference, the output can either be a bipolar ±16.5V voltage when operating from dual ±17V (or higher) power supplies, or a unipolar 0V to +33V voltage when operating from a +33.5V (or higher) power supply. This DAC provides low-power operation, good linearity, and low glitch over the specified temperature range of –40°C to +105°C. This device is trimmed in manufacturing and has very low zero-code and gain error. In addition, system level calibration can be performed to achieve ±1 LSB bipolar zero/full-scale error with bipolar supplies, or ±1 LSB zero code/full-scale error with a unipolar supply, over the entire signal chain. The output range can be offset by using the DAC offset register.

The DAC8718 features a standard, high-speed serial peripheral interface (SPI) that operates at up to 50MHz and is 1.8V, 3V, and 5V logic compatible, to communicate with a DSP or microprocessor. The input data of the device are double-buffered. An asynchronous load input (LDAC) transfers data from the DAC data register to the DAC latch. The asynchronous CLR input sets the output of all eight DACs to AGND. The V that connects to the individual analog outputs, the offset DAC, the reference buffer outputs, and two external inputs through a multiplexer (mux).

The DAC8718 is pin-to-pin and function-compatible with the DAC8218 (14-bit) and the DAC7718 (12-bit).

pin is a monitor output

MON

2DSP is a trademark of Texas Instruments. 3SPI, QSPI are trademarks of Motorola Inc. 4Microwire is a trademark of National Semiconductor. 5All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of allparameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

www.ti.com

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

ORDERING INFORMATION

(1)

RELATIVE DIFFERENTIAL SPECIFIED

ACCURACY LINEARITY PACKAGE- PACKAGE TEMPERATURE PACKAGE

PRODUCT (LSB) (LSB) LEAD DESIGNATOR RANGE MARKING

DAC8718

±4 ±1 QFN-48 RGZ –40°C to +105°C DAC8718 ±4 ±1 TQFP-64 PAG –40°C to +105°C DAC8718

(1) For the most current package and ordering information, see the Package Option Addendum at the end of this data sheet, or see the TI

web site at www.ti.com.

ABSOLUTE MAXIMUM RATINGS

(1)

Over operating free-air temperature range (unless otherwise noted).

DAC8718 UNIT

AVDDto AV

AVDDto AGND –0.3 to 38 V AVSSto AGND, DGND –19 to 0.3 V DVDDto DGND –0.3 to 6 V IOVDDto DGND –0.3 to min of (6 or DVDD+ 0.3) V AGND-x to DGND –0.3 to 0.3 V Digital input voltage to DGND –0.3 to IOVDD+ 0.3 V SDO to DGND –0.3 to IOVDD+ 0.3 V V

OUT

-x, V

, AIN-x to AV

MON

REF-A, REF-B to AGND –0.3 to DV GPIO-n to DGND –0.3 to IOVDD+ 0.3 V GPIO-n input current 5 mA Maximum current from V

MON

Operating temperature range –40 to +105 °C Storage temperature range –65 to +150 °C Maximum junction temperature (TJmax) +150 °C

Human body model (HBM) 2.5 kV

ESD ratings Charged device model (CDM) 1000 V

Machine model (MM) 200 V

TQFP 55 °C/W QFN 27.5 °C/W TQFP 21 °C/W QFN 10.8 °C/W

Thermal impedance

Junction-to-ambient, θ

Junction-to-case, θ

Power dissipation (TJmax – TA) / θ

(1) Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to absolute

maximum conditions for extended periods may affect device reliability.

–0.3 to 38 V

–0.3 to AVDD+ 0.3 V

3 mA

Product Folder Link(s): DAC8718

DAC8718

www.ti.com

SBAS467A –MAY 2009–REVISED DECEMBER 2009

ELECTRICAL CHARACTERISTICS: Dual-Supply

All specifications at TA= T gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

STATIC PERFORMANCE

Resolution 16 Bits Linearity error Measured by line passing through codes 0000h and FFFFh ±4 LSB Differential linearity error Measured by line passing through codes 0000h and FFFFh ±1 LSB

Bipolar zero error TA= +25°C, before user calibration, gain = 4, code = 8000h ±15 LSB

Bipolar zero error TC Gain = 4 or 6, code = 8000h ±0.5 ±2 ppm FSR/°C

Zero-code error

Zero-code error TC Gain = 4 or 6, code = 0000h ±0.5 ±3 ppm FSR/°C

Gain error

Gain error TC Gain = 4 or 6 ±1 ±3 ppm FSR/°C

Full-scale error TA= +25°C, before user calibration, gain = 4, code = FFFFh ±15 LSB

Full-scale error TC Gain = 4 or 6, code = FFFFh ±0.5 ±3 ppm FSR/°C DC crosstalk

(3)

(1) Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary

no more than ±10 LSB from the nominal number listed in Table 7. The Offset DAC pins are not intended to drive an external load, and

must not be connected during dual-supply operation. (2) Gain = 4 and TC specified by design and characterization. (3) The DAC outputs are buffered by op amps that share common AVDDand AVSSpower supplies. DC crosstalk indicates how much dc

change in one or more channel outputs may occur when the dc load current changes in one channel (because of an update). With

high-impedance loads, the effect is virtually immeasurable. Multiple AVDDand AVSSterminals are provided to minimize dc crosstalk.

(2)

to T

MIN

TA= +25°C, before user calibration, gain = 6, code = 8000h ±10 LSB

TA= +25°C, after user calib., gain = 4 or 6, code = 8000h ±1 LSB

TA= +25°C, gain = 6, code = 0000h ±10 LSB TA= +25°C, gain = 4, code = 0000h ±15 LSB

TA= +25°C, gain = 6 ±10 LSB TA= +25°C, gain = 4 ±15 LSB

TA= +25°C, before user calibration, gain = 6, code = FFFFh ±10 LSB

TA= +25°C, after user calib., gain = 4 or 6, code = FFFFh ±1 LSB

Measured channel at code = 8000h, full-scale change on any other channel

, AVDD= +16.5V, AVSS= –16.5V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V,

MAX

DAC8718

0.2 LSB

(1)

Product Folder Link(s): DAC8718

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

www.ti.com

ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)

All specifications at TA= T gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

ANALOG OUTPUT (V

Voltage output

Output impedance Code = 8000h 0.5 Ω Short-circuit current Load current See Figure 37 ±3 mA

Output drift vs time

Capacitive load stability 500 pF

Settling time 15 μs

Slew rate Power-on delay Power-down recovery time 60 μs Digital-to-analog glitch Glitch impulse peak amplitude Code from 7FFFh to 8000h and 8000h to 7FFFh 5 mV Channel-to-channel isolation

DAC-to-DAC crosstalk

Digital crosstalk Digital feedthrough

Output noise TA= +25°C at 10kHz, gain = 4 130 nV/√Hz

Power-supply rejection

(5)

(7)

(8)

(12)

(4) Specified by design. (5) The analog output range of V

the analog output must not be greater than (AVDD– 0.5V), and the minimum value must not be less than (AVSS+ 0.5V). All

specifications are for a ±16.5V power supply and a ±15V output, unless otherwise noted. (6) When the output current is greater than the specification, the current is clamped at the specified maximum value. (7) Slew rate is measured from 10% to 90% of the transition when the output changes from 0 to full-scale. (8) Power-on delay is defined as the time from when the supply voltages reach the specified conditions to when CS goes low, for valid

digital communication. (9) Digital-to-analog glitch is defined as the amount of energy injected into the analog output at the major code transition. It is specified as

the area of the glitch in nV-s. It is measured by toggling the DAC register data between 7FFFh and 8000h in straight binary format. (10) Channel-to-channel isolation refers to the ratio of the signal amplitude at the output of one DAC channel to the amplitude of the

sinusoidal signal on the reference input of another DAC channel. It is expressed in dB and measured at midscale. (11) DAC-to-DAC crosstalk is the glitch impulse that appears at the output of one DAC as a result of both the full-scale digital code and

subsequent analog output change at another DAC. It is measured with LDAC tied low and expressed in nV-s. (12) Digital crosstalk is the glitch impulse transferred to the output of one converter as a result of a full-scale code change in the DAC input

register of another converter. It is measured when the DAC output is not updated, and is expressed in nV-s. (13) Digital feedthrough is the glitch impulse injected to the output of a DAC as a result of a digital code change in the DAC input register of

the same DAC. It is measured with the full-scale digital code change without updating the DAC output, and is expressed in nV-s. (14) The output must not be greater than (AVDD– 0.5V) and not less than (AVSS+ 0.5V).

(13)

-0 to V

OUT

(6)

(9)

(11)

(14)

to T

MIN

-7)

OUT

V V

TA= +25°C, device operating for 500 hours, full-scale output 3.4 ppm of FSR TA= +25°C, device operating for 1000 hours, full-scale output 4.3 ppm of FSR

To 0.03% of FSR, CL= 200pF, RL= 10kΩ, code from 0000h to FFFFh and FFFFh to 0000h

To 1 LSB, CL= 200pF, RL= 10kΩ, code from 0000h to FFFFh and FFFFh to 0000h

To 1 LSB, CL= 200pF, RL= 10kΩ, code from 7F00h to 8100h and 8100h to 7F00h

From IOVDD≥ +1.8V and DVDD≥ +2.7V to CS low 200 μs

Code from 7FFFh to 8000h and 8000h to 7FFFh 4 nV-s

(10)

V DACs in the same group 7.5 nV-s DACs among different groups 1 nV-s

TA= +25°C at 10kHz, gain = 6 200 nV/√Hz

0.1Hz to 10Hz, gain = 6 20 μV AVDD= ±15.5V to ±16.5V 0.05 LSB

, AVDD= +16.5V, AVSS= –16.5V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V,

MAX

DAC8718

(4)

= +5V –15 +15 V

REF

= +1.5V –4.5 +4.5 V

REF

±8 mA

10 μs

6 μs 6 V/μs

= 4VPP, f = 1kHz 88 dB

REF

1 nV-s 1 nV-s

OUT

-0 to V

-7 is equal to (6 × V

OUT

– 5 × OUTPUT_OFFSET_DAC) for gain = 6. The maximum value of

REF

(1)

Product Folder Link(s): DAC8718

DAC8718

www.ti.com

SBAS467A –MAY 2009–REVISED DECEMBER 2009

ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)

All specifications at TA= T gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

OFFSET DAC OUTPUT

Voltage output V Full-scale error TA= +25°C ±4 LSB Zero-code error TA= +25°C ±2 LSB Linearity error ±6 LSB Differential linearity error ±1 LSB

ANALOG MONITOR PIN (V

Output impedance Three-state leakage current 100 nA

AUXILIARY ANALOG INPUT

Input range AV Input impedance

(AIN-x to V

MON

) Input capacitance Input leakage current 30 nA

REFERENCE INPUT

Reference input voltage range Reference input dc impedance 10 MΩ Reference input capacitance

DIGITAL INPUT

High-level input voltage, V

Low-level input voltage, V

Input current

Input capacitance USB/BTC and RSTSEL 12 pF

DIGITAL OUTPUT

High-level output voltage, V (SDO)

Low-level output voltage, V (SDO)

GPIO-n output voltage low, V GPIO-n output voltage high, VOH10kΩ pull-up resistor to IOV High-impedance leakage current SDO and GPIO-n ±5 μA

High-impedance output capacitance

(15) Specified by design. (16) Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary

no more than ±10 LSB from the nominal number listed in Table 7. The Offset DAC pins are not intended to drive an external load, and

must not be connected during dual-supply operation. (17) 8kΩ when V (18) Reference input voltage ≤ DVDD.

(15) (16)

(17)

(15)

is connected to Reference Buffer A or B, and 4kΩ when V

MON

to T

MIN

, AVDD= +16.5V, AVSS= –16.5V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V,

MAX

DAC8718

= +5V 0 5 V

REF

)

MON

TA= +25°C 2 kΩ

TA= +25°C 2 kΩ

4 pF

(18)

(15)

1.0 5.5 V

10 pF

IOVDD= +4.5V to +5.5V 3.8 0.3 + IOV IOVDD= +2.7V to +3.3V 2.3 0.3 + IOV IOVDD= +1.7V to 2.0V 1.5 0.3 + IOV IOVDD= +4.5V to +5.5V –0.3 0.8 V IOVDD= +2.7V to +3.3V –0.3 0.6 V IOVDD= +1.7V to 2.0V –0.3 0.3 V CLR, LDAC, RST, CS, and SDI ±1 μA USB/BTC, RSTSEL, and GPIO-n ±5 μA CLR, LDAC, RST, CS, and SDI 5 pF

GPIO-n 14 pF

IOVDD= +2.7V to +5.5V, sourcing 1mA IOVDD– 0.4 IOV IOVDD= +1.8V, sourcing 200μA 1.6 IOV IOVDD= +2.7V to +5.5V, sinking 1mA 0 0.4 V IOVDD= +1.8V, sinking 200μA 0 0.2 V 1mA sink from IOV

0.99 × IOV

0.15 V

SDO 5 pF GPIO-n 14 pF

is connected to Offset DAC-A or -B.

MON

(1)

DD DD DD

DD DD

V V V

V V

Product Folder Link(s): DAC8718

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

www.ti.com

ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)

All specifications at TA= T gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

POWER SUPPLY

(19)

IOV

IOI

Power dissipation Normal operation, ±16.5V supplies, midscale code 115 165 mW

TEMPERATURE RANGE

Specified performance –40 +105 °C

(19) IOVDD≤ DVDD.

to T

MIN

Normal operation, midscale code, output unloaded 4.3 6 mA Power down, output unloaded 35 μA Normal operation, midscale code, output unloaded –4 –2.7 mA Power down, output unloaded 35 μA Normal operation 78 μA Power down 36 μA Normal operation, VIH= IOVDD, VIL= DGND 5 μA Power down, VIH= IOVDD, VIL= DGND 5 μA

, AVDD= +16.5V, AVSS= –16.5V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V,

MAX

DAC8718

+4.5 +18 V

–18 –4.5 V +2.7 +5.5 V +1.8 +5.5 V

(1)

Product Folder Link(s): DAC8718

DAC8718

www.ti.com

SBAS467A –MAY 2009–REVISED DECEMBER 2009

ELECTRICAL CHARACTERISTICS: Single-Supply

All specifications at TA= T AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

STATIC PERFORMANCE

Resolution 16 Bits Linearity error Measured by line passing through codes 0100h and FFFFh ±4 LSB Differential linearity error Measured by line passing through codes 0100h and FFFFh ±1 LSB

Unipolar zero error TA= +25°C, before user calibration, gain = 4, code = 0100h ±15 LSB

Unipolar zero error TC Gain = 4 or 6, code = 0100h ±0.5 ±3 ppm FSR/°C

Gain error

Gain error TC Gain = 4 or 6 ±1 ±3 ppm FSR/°C

Full-scale error TA= +25°C, before user calibration, gain = 4, code = FFFFh ±15 LSB

Full-scale error TC Gain = 4 or 6, code = FFFFh ±0.5 ±3 ppm FSR/°C DC crosstalk

ANALOG OUTPUT (V

Voltage output

Output impedance Code = 8000h 0.5 Ω Short-circuit current Load current SeeFigure 84 and Figure 85 ±3 mA

Output drift vs time

Capacitive load stability 500 pF

Settling time 15 μs

Slew rate Power-on delay Power-down recovery time 90 μs Digital-to-analog glitch Glitch impulse peak amplitude Code from 7FFFh to 8000h and 8000h to 7FFFh 5 mV Channel-to-channel isolation

(2)

(4)

(6)

(7)

(1) Gain = 4 and TC specified by design and characterization. (2) The DAC outputs are buffered by op amps that share common AVDDand AVSSpower supplies. DC crosstalk indicates how much dc

change in one or more channel outputs may occur when the dc load current changes in one channel (because of an update). With

high-impedance loads, the effect is virtually immeasurable. Multiple AVDDand AVSSterminals are provided to minimize dc crosstalk. (3) Specified by design. (4) The analog output range of V

greater than (AVDD– 0.5V). All specifications are for a +32V power supply and a 0V to +30V output, unless otherwise noted. (5) When the output current is greater than the specification, the current is clamped at the specified maximum value. (6) Slew rate is measured from 10% to 90% of the transition when the output changes from 0 to full-scale. (7) Power-on delay is defined as the time from when the supply voltages reach the specified conditions to when CS goes low, for valid

digital communication. (8) Digital-to-analog glitch is defined as the amount of energy injected into the analog output at the major code transition. It is specified as

the area of the glitch in nV-s. It is measured by toggling the DAC register data between 7FFFh and 8000h in straight binary format. (9) Channel-to-channel isolation refers to the ratio of the signal amplitude at the output of one DAC channel to the amplitude of the

sinusoidal signal on the reference input of another DAC channel. It is expressed in dB and measured at midscale.

(1)

-0 to V

OUT

(5)

(8)

to T

MIN

TA= +25°C, before user calibration, gain = 6, code = 0100h ±10 LSB

TA= +25°C, after user calib., gain = 4 or 6, code = 0100h ±1 LSB

TA= +25°C, gain = 6 ±10 LSB TA= +25°C, gain = 4 ±15 LSB

TA= +25°C, before user calibration, gain = 6, code = FFFFh ±10 LSB

TA= +25°C, after user calib., gain = 4 or 6, code = FFFFh ±1 LSB

Measured channel at code = 8000h, full-scale change on any other channel

-7)

OUT

REF

TA= +25°C, device operating for 500 hours, full-scale output 3.4 ppm of FSR TA= +25°C, device operating for 1000 hours, full-scale output 4.3 ppm of FSR

To 0.03% of FSR, CL= 200pF, RL= 10kΩ, code from 0100h to FFFFh and FFFFh to 0100h

To 1 LSB, CL= 200pF, RL= 10kΩ, code from 0100h to FFFFh and FFFFh to 0100h

To 1 LSB, CL= 200pF, RL= 10kΩ, code from 7F00h to 8100h and 8100h to 7F00h

From IOVDD≥ +1.8V and DVDD≥ +2.7V to CS low 200 μs

Code from 7FFFh to 8000h and 8000h to 7FFFh 4 nV-s

(9)

REF

, AVDD= +32V, AVSS= 0V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V, gain = 6,

MAX

DAC8718

0.2 LSB

(3)

= +5V 0 +30 V = +1.5V 0 +9 V

±8 mA

10 μs

6 μs 6 V/μs

= 4VPP, f = 1kHz 88 dB

OUT

-0 to V

-7 is equal to (6 × V

OUT

) for gain = 6. The maximum value of the analog output must not be

REF

Product Folder Link(s): DAC8718

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

www.ti.com

ELECTRICAL CHARACTERISTICS: Single-Supply (continued)

All specifications at TA= T AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

DAC-to-DAC crosstalk

Digital crosstalk Digital feedthrough

Output noise TA= +25°C at 10kHz, gain = 4 130 nV/√Hz

Power-supply rejection

ANALOG MONITOR PIN (V

Output impedance Three-state leakage current 100 nA

AUXILIARY ANALOG INPUT

Input range AV Input impedance

(AIN-x to V

MON

Input capacitance Input leakage current 30 nA

REFERENCE INPUT

Reference input voltage

(16)

range Reference input dc impedance 10 MΩ Reference input capacitance

DIGITAL INPUT

High-level input voltage, V

Low-level input voltage, V

Input current

Input capacitance USB/BTC and RSTSEL 12 pF

(10) DAC-to-DAC crosstalk is the glitch impulse that appears at the output of one DAC as a result of both the full-scale digital code and

subsequent analog output change at another DAC. It is measured with LDAC tied low and expressed in nV-s. (11) Digital crosstalk is the glitch impulse transferred to the output of one converter as a result of a full-scale code change in the DAC input

register of another converter. It is measured when the DAC output is not updated, and is expressed in nV-s. (12) Digital feedthrough is the glitch impulse injected to the output of a DAC as a result of a digital code change in the DAC input register of

the same DAC. It is measured with the full-scale digital code change without updating the DAC output, and is expressed in nV-s. (13) The analog output must not be greater than (AVDD– 0.5V). (14) 8kΩ when V (15) Specified by design. (16) Reference input voltage ≤ DVDD.

(10)

(11)

(12)

(13)

(14)

)

(15)

is connected to Reference Buffer A or B, and 4kΩ when V

MON

to T

MIN

, AVDD= +32V, AVSS= 0V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V, gain = 6,

MAX

DAC8718

DACs in the same group 10 nV-s DACs among different groups 1 nV-s

1 nV-s 1 nV-s

TA= +25°C at 10kHz, gain = 6 200 nV/√Hz

0.1Hz to 10Hz, gain = 6 20 μV AVDD= +33V to +36V 0.05 LSB

)

MON

TA= +25°C 2 kΩ

TA= +25°C 2 kΩ

4 pF

1.0 5.5 V

(15)

IOVDD= +4.5V to +5.5V 3.8 0.3 + IOV IOVDD= +2.7V to +3.3V 2.3 0.3 + IOV IOVDD= +1.7V to 2.0V 1.5 0.3 + IOV

10 pF

DD DD DD

IOVDD= +4.5V to +5.5V –0.3 0.8 V IOVDD= +2.7V to +3.3V –0.3 0.6 V IOVDD= +1.7V to 2.0V –0.3 0.3 V CLR, LDAC, RST, CS, and SDI ±1 μA USB/BTC, RSTSEL, and GPIO-n ±5 μA CLR, LDAC, RST, CS, and SDI 5 pF

GPIO-n 14 pF

is connected to Offset DAC-A or -B.

MON

V V V

Product Folder Link(s): DAC8718

DAC8718

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

ELECTRICAL CHARACTERISTICS: Single-Supply (continued)

All specifications at TA= T AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNIT

DIGITAL OUTPUT

High-level output voltage, V (SDO)

Low-level output voltage, V (SDO)

GPIO-n output voltage low, VOL1mA sink from IOV GPIO-n output voltage high, VOH10kΩ pull-up resistor to IOV High-impedance leakage current SDO and GPIO-n ±5 μA

High-impedance output capacitance

POWER SUPPLY

(18)

IOV

IOI

Power dissipation Normal operation 140 225 mW

TEMPERATURE RANGE

Specified performance –40 +105 °C

(17) Specified by design. (18) IOVDD≤ DVDD.

(17)

to T

MIN

, AVDD= +32V, AVSS= 0V, IOVDD= DVDD= +5V, REF-A and REF-B = +5V, gain = 6,

MAX

DAC8718

IOVDD= +2.7V to +5.5V, sourcing 1mA IOVDD– 0.4 IOV IOVDD= +1.8V, sourcing 200μA 1.6 IOV

DD DD

IOVDD= +2.7V to +5.5V, sinking 1mA 0 0.4 V IOVDD= +1.8V, sinking 200μA 0 0.2 V

0.99 × IOV

0.15 V

SDO 5 pF GPIO-n 14 pF

+9 +36 V +2.7 +5.5 V +1.8 +5.5 V

Normal operation, midscale code, output unloaded 4.5 7 mA Power down, output unloaded 35 µA Normal operation 70 μA Power down 36 μA Normal operation, VIH= IOVDD, VIL= DGND 5 μA Power down, VIH= IOVDD, VIL= DGND 5 μA

V V

Product Folder Link(s): DAC8718

ControlLogic

An ogal Monit ro

ToDAC-0,DAC-1,

DAC-2,DAC-3

ToDAC-0,DAC-1,

DAC-2,DAC-3

ToDAC-4,DAC-5,DAC-6,DAC-7

DAC8718

OFFSET-B

AGND-B

V -7

OUT

MON

OFFSET-A

AGND-A

REF-B

Reference

BufferB

InternalTrimming

Zero/Gain;INL

Reference

BufferA

OFFSET

DACA

OFFSET

DACB

DAC-0

Latch-0

Power-Up/

Power-Down

Control

(SameFunctionBlocks

forAllChannels)

REF-A

LDAC

RST

RSTSEL

LDAC

CLR

USB/BTC

AIN-0

AIN-1

GPIO-0 GPIO-1 GPIO-2

SDO

SDI

SCLK

WAKEUP

SPIShiftRegister

IOVDDDGND DV

DGND DV

V -0

OUT

V -7

OUT

AIN-0

AIN-1 RefBufferA RefBufferB

OFFSET-B

Mux

Command

Registers

InputData Register0

Correction

Engine

(WhenCorrectionEngineDisabled)

DAC-0

Data

UserCalibration:

ZeroRegister0 GainRegsiter0

V -0

OUT

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

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FUNCTIONAL BLOCK DIAGRAM

Figure 1. Functional Block Diagram

Product Folder Link(s): DAC8718

AIN-1

V -4

OUT

REF-B

V -5

OUT

V -6

OUT

AGND-B

OFFSET-B

V -7

OUT

AIN-0

V -3

OUT

REF-A

V -2

OUT

V -1

OUT

AGND-A

OFFSET-A

V -0

OUT

MON

WAKEUP

LDAC

SDONCSDICSSCLK

IOV

DGNDNCNC

RSTSEL

USB/BTC

GPIO-2

CLR

RST

DGND

GPIO-1

GPIO-0

64 63 62 61 60 59 58 57 56 55 54

18 19 20

21 222324

25 26

53 52 51 50 49

28 29 30 31 32

DAC8718

AIN-0

V -3

OUT

REF-A

V -2

OUT

V -1

OUT

AGND-A

OFFSET-A

V -0

OUT

MON

AIN-1

V -4

OUT

REF-B

V -5

OUT

V -6

OUT

AGND-B

OFFSET-B

V -7

OUT

DAC8718

WAKEUP

LDAC

SDO

SDICSSCLK

IOV

DGNDNCRSTSEL

USB/BTC

4847464544434241403938

GPIO-2

CLR

RST

DGND

GPIO-1

GPIO-0

1314151617181920212223

DAC8718

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PAG PACKAGE

TQFP-64

(TOP VIEW)

SBAS467A –MAY 2009–REVISED DECEMBER 2009

PIN CONFIGURATIONS

RGZ PACKAGE

QFN-48

(TOP VIEW)

NAME

AIN-0 2 3 I Auxiliary analog input 0, directly routed to the analog mux

-3 3 4 O DAC-3 output

OUT

REF-A 4 5 I Group A V

-2 5 6 O DAC-2 output

OUT

-1 6 7 O DAC-1 output

OUT

AGND-A 7 8 I Group A analog ground and the ground of REF-A. This pin must be tied to AGND-B and DGND. AGND-A 8 9 I Group A analog ground and the ground of REF-A. This pin must be tied to AGND-B and DGND.

OFFSET-A 9 10 O

(1) Group A consists of DAC-0, DAC-1, DAC-2, and DAC-3. Group B consists of DAC-4, DAC-5, DAC-6, and DAC-7.

-0 10 11 O DAC-0 output

OUT

MON

GPIO-2 13 19 I/O

CLR 14 20 I through switches and internal low-impedance. When the CLR pin is logic '1', all V

RST 15 21 I

(1) The thermal pad is internally connected to

the substrate. This pad can be connected to AVSSor left floating. Keep the thermal pad separate from the digital ground, if possible.

PIN DESCRIPTIONS

PIN NO.

QFN-48 TQFP-64 I/O DESCRIPTION

1 1 I Positive analog power supply

(1)

reference input

11 12 I Negative analog power supply

12 14 O reference buffer outputs, offset DAC outputs, or one of the auxiliary analog inputs, depending on

OFFSET DAC-A analog output. Must be connected to AGND-A during single power-supply operation (AVSS= 0V). This pin is not intended to drive an external load.

Analog monitor output. This pin is either in Hi-Z status, connected to one of the eight DAC outputs, the content of the Monitor Register. See the Monitor Register, Table 12, for details.

General-purpose digital input/output 2. This pin is a bidirectional digital input/output, open-drain and requires an external pull-up resistor. See the GPIO Pins section for details.

Clear input, level triggered. When the CLR pin is logic '0', all V connect to the amplifier outputs.

Reset input (active low). Logic low on this pin resets the DAC registers and DACs to the values defined by the RSTSEL pin. CS must be logic high when RST is active.

Product Folder Link(s): DAC8718

-X pins connect to AGND-x

OUT

-X pins

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

PIN DESCRIPTIONS (continued)

NAME

DGND 20 25 I Digital ground DGND 22 28 I Digital ground

GPIO-1 23 29 I/O

GPIO-0 24 30 I/O

-7 27 38 O DAC-7 output

OUT

OFFSET-B 28 39 O

AGND-B 29 40 I Group B AGND-B 30 41 I Group B analog ground and the ground of REF-B. This pin must be tied to AGND-A and DGND.

-6 31 42 O DAC-6 output

OUT

-5 32 43 O DAC-5 output

OUT

REF-B 33 44 I Group B reference input V

-4 34 45 O DAC-4 output

OUT

AIN-1 35 46 I Auxiliary analog input 1, directly routed to the analog mux

USB/BTC 37 50 I when connected to DGND or in twos complement format when connected to IOVDD. The command

RSTSEL 38 51 I

DGND 40 54 I Digital ground

IOV

SCLK 43 57 I SPI bus serial clock input

CS 44 58 I

SDI 45 59 I SPI bus serial data input

SDO 46 61 O

LDAC 47 62 I

WAKEUP 48 63 I

NC — Not connected

PIN NO.

QFN-48 TQFP-64 I/O DESCRIPTION

17 24 I Digital power supply

General-purpose digital input/output 1. This pin is a bidirectional digital input/output, open-drain and requires an external resistor. See the GPIO Pins section for details.

General-purpose digital input/output 0. This pin is a bidirectional digital input/output, open-drain and requires an external resistor. See the GPIO Pins section for details.

26 37 I Negative analog power supply

OFFSET DAC-B analog output. Must be connected to AGND-B during single-supply operation (AVSS= 0V).

(1)

analog ground and the ground of REF-B. This pin must be tied to AGND-A and DGND.

36 48 I Positive analog power supply

Data format selection of Input DAC data and Offset DAC data. Data are in straight binary format data are always in straight binary format. Refer to Input Data Format section for details.

Output reset selection. Selects the output voltage on the V Refer to the Power-On Reset section for details.

41 55 I Interface power 42 56 I Digital power supply

SPI bus chip select input (active low). Data are not clocked into SDI unless CS is low. When CS is high, SDO is in a high-impedance state and the SCLK and SDI signals are blocked from the device.

SPI bus serial data output. When the DSDO bit = '0', the SDO pin works as an output in normal operation. When the DSDO bit = '1', SDO is always in a Hi-Z state, regardless of the CS pin status. Refer to the Timing Diagrams section for details.

Load DAC latch control input (active low). When LDAC is low, the DAC latch is transparent and the contents of the DAC Data Register are transferred to it. The DAC output changes to the corresponding level simultaneously when the DAC latch is updated. See the Updating the DAC

Outputs section for details. If asynchronous mode is desired, LDAC must be permanently tied low

before power is applied to the device. If synchronous mode is desired, LDAC must be logic high during power-on.

Wake-up input (active low). Restores the SPI from sleep to normal operation. See the Daisy-Chain

Operation section for details.

2, 13,

15-18, 22,

16, 18, 19, 23, 26, 27,

21, 25, 39 31-36, 47,

49, 52, 53,

60, 64

pin after power-on or hardware reset.

OUT

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Product Folder Link(s): DAC8718

SCLK

InputDataRegisterand

DACLatchUpdated

WhenCorrectionCompletes

(1)

DACLatchUpdated

(2)

SDI

BIT23(MSB)

BIT22 BIT1

Low

BIT0

LDAC

Ifthecorrectionengineisoff,theDAClatchisreloadedimmediatelyaftertheDACDataRegisterisupdated.NOTE:(1)

TheDAClatchisupdatedwhen goeslow,aslongasthetimingrequirementoft issatisfied.

LDAC

NOTE:(2)

Case1:Standalonemode:Updatewithout pin; tiedtologiclowLDAC LDAC pin .

SCLK

InputDataRegisterUpdated,

butDACLatchisNot Updated

SDI

BIT22 BIT1

High

BIT0

LDAC

Case2:Standalonemode:Updatewith pin.LDAC

=Don’tCare

Bit23=MSB Bit0=LSB

DAC8718

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TIMING DIAGRAMS

SBAS467A –MAY 2009–REVISED DECEMBER 2009

Figure 2. SPI Timing for Standalone Mode

Product Folder Link(s): DAC8718

SCLK

SDI

BIT23(N)

BIT22(N) BIT0(N) BIT23(N+1)

BIT23(N) BIT0(N)

Low

BIT0(N+1)

SDO

LDAC

Ifthecorrectionengineisoff,theDAClatchisreloadedimmediatelyaftertheDACDataRegisterisupdated.NOTE:(1)

TheDAClatchisupdatedwhen goeslow.Theproperdataareloadedifthet timingrequirementissatisfied. Otherwise,invaliddataareloaded.

LDAC

NOTE:(2)

Case3:Daisy-ChainMode:Updatewithout pin; pintiedtologiclow.LDAC LDAC

High

LDAC

=Don’tCare

Bit23=MSB Bit0=LSB

SCLK

InputDataRegisterUpdated,

butDACLatchisNotUpdated

SDI

BIT23(N)

BIT22(N) BIT0(N) BIT23(N+1)

BIT23(N) BIT0(N)

BIT0(N+1)

SDO

Case4:Daisy-ChainMode:Updatewith pin.LDAC

DACLatchUpdated

(2)

InputDataRegisterand

DACLatchUpdated

WhenCorrectionCompletes

(1)

DB23 DB0

Case5:Daisy-ChainMode:Sleeping.

SCLK

SDI

FirstWord LastWord

DB23 DB0

SDO

DB23 DB0

Hi-Z

Hi-Z Hi-Z Hi-Z

Hi-Z Hi-Z

Hi-Z

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TIMING DIAGRAMS (continued)

www.ti.com

Figure 3. SPI Timing for Daisy-Chain Mode

Product Folder Link(s): DAC8718

Case6:ReadbackforStandalonemode.

BIT23(=1) BIT22

InputWordSpecifiesRegistertobeRead

NOPCommand(write ‘1’ toNOPbit)

DatafromtheSelectedRegister

BIT0

BIT23

BIT23(=1)

BIT22

BIT1

BIT0

InternalRegisterUpdated

SCLK

SDI

SDO

LDAC

Low

=Don’tCare

Bit23=MSB Bit0=LSB

Hi-Z Hi-Z Hi-Z

DAC8718

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TIMING DIAGRAMS (continued)

Figure 4. SPI Timing for Readback Operation in Standalone Mode

SBAS467A –MAY 2009–REVISED DECEMBER 2009

Product Folder Link(s): DAC8718

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TIMING CHARACTERISTICS: IOVDD= +5V

(1)(2)(3)(4)

At –40°C to +105°C, DVDD= +5V, and IOVDD= +5V, unless otherwise noted.

PARAMETER MIN MAX UNIT

SCLK

Clock frequency 50 MHz SCLK cycle time 20 ns SCLK high time 10 ns SCLK low time 7 ns CS falling edge to SCLK falling edge setup time 8 ns SDI setup time before falling edge of SCLK 5 ns SDI hold time after falling edge of SCLK 5 ns SCLK falling edge to CS rising edge 5 ns CS high time 10 ns CS rising edge to LDAC falling edge 5 ns LDAC pulse duration 10 ns Delay from SCLK rising edge to SDO valid 3 8 ns Delay from CS rising edge to SDO Hi-Z 5 ns Delay from CS falling edge to SDO valid 6 ns SDI to SDO delay during sleep mode 2 5 ns

(1) Specified by design. Not production tested. (2) Sample tested during the initial release and after any redesign or process changes that may affect these parameters. (3) All input signals are specified with tR= tF= 2ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2. (4) SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications, with tR= tF≤ 5ns.

BLANKSPACE

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TIMING CHARACTERISTICS: IOVDD= +3V

(1)(2)(3)(4)

At –40°C to +105°C, DVDD= +3V/+5V, and IOVDD= +3V, unless otherwise noted.

PARAMETER MIN MAX UNIT

SCLK

(1) Specified by design. Not production tested. (2) Sample tested during the initial release and after any redesign or process changes that may affect these parameters. (3) All input signals are specified with tR= tF= 3ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2. (4) SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications, with tR= tF≤ 5ns.

Clock frequency 25 MHz SCLK cycle time 40 ns SCLK high time 19 ns SCLK low time 7 ns CS falling edge to SCLK falling edge setup time 15 ns SDI setup time before falling edge of SCLK 5 ns SDI hold time after falling edge of SCLK 5 ns SCLK falling edge to CS rising edge 10 ns CS high time 19 ns CS rising edge to LDAC falling edge 5 ns LDAC pulse duration 10 ns Delay from SCLK rising edge to SDO valid 3 15 ns Delay from CS rising edge to SDO Hi-Z 7 ns Delay from CS falling edge to SDO valid 10 ns SDI to SDO delay during sleep mode 2 10 ns

Product Folder Link(s): DAC8718

DAC8718

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TIMING CHARACTERISTICS: IOVDD= +1.8V

(1)(2)(3)(4)

SBAS467A –MAY 2009–REVISED DECEMBER 2009

At –40°C to +105°C, DVDD= +3V/+5V, and IOVDD= +1.8V, unless otherwise noted.

PARAMETER MIN MAX UNIT

SCLK

(1) Specified by design. Not production tested. (2) Sample tested during the initial release and after any redesign or process changes that may affect these parameters. (3) All input signals are specified with tR= tF= 6ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2. (4) SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications, with tR= tF≤ 15ns.

Clock frequency 16.6 MHz SCLK cycle time 60 ns SCLK high time 28 ns SCLK low time 7 ns CS falling edge to SCLK falling edge setup time 28 ns SDI setup time before falling edge of SCLK 10 ns SDI hold time after falling edge of SCLK 5 ns SCLK falling edge to CS rising edge 10 ns CS high time 28 ns CS rising edge to LDAC falling edge 5 ns LDAC pulse duration 10 ns Delay from SCLK rising edge to SDO valid 3 25 ns Delay from CS rising edge to SDO Hi-Z 15 ns Delay from CS falling edge to SDO valid 23 ns SDI to SDO delay during sleep mode 2 25 ns

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

AllEightChannelsShown

8192

65536573444915240960327682457616384

DigitalInputCode

AllEightChannelsShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

Gain=4

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

Gain=4

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Bipolar

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (All 8 Channels) vs DIGITAL INPUT CODE (All 8 Channels)

Figure 5. Figure 6.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+25°C) vs DIGITAL INPUT CODE (+25°C)

www.ti.com

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 7. Figure 8.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

DAC8718

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TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (–40°C) vs DIGITAL INPUT CODE (–40°C)

Figure 9. Figure 10.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+25°C) vs DIGITAL INPUT CODE (+25°C)

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 11. Figure 12.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+105°C) vs DIGITAL INPUT CODE (+105°C)

Figure 13. Figure 14.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature( C)°

INLMax

INLMin

1.0

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

DNLError(LSB)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

DNLMin

DNLMax

-1

-2

-3

-4

INLError(LSB)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature( C)°

Gain=4

INLMax

INLMin

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Gain=4

1.0

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

DNLError(LSB)

DNLMax

DNLMin

-1

-2

-3

-4

INLError(LSB)

1.0 5.55.04.54.03.53.01.5 2.0 V (V)

REF

INLMax

AVDD=+18V

AV = -SS18V

INLMin

2.5

1.0 5.55.04.54.03.53.01.5 2.0 V (V)

REF

2.5

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

AVDD=+18V AV = -SS18V

DNLMax

DNLMin

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE vs TEMPERATURE

Figure 15. Figure 16.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE vs TEMPERATURE

www.ti.com

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 17. Figure 18.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 19. Figure 20.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 AV = AV (V)-

DD S S

INLMax

DVDD=IOVDD=4.5V

V =2.048V

REF

Gain=4

INLMin

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 AV =

DD S S

-AV (V)

DNLMax

DD DD

=IOV =4.5V

V =2.048V

REF

Gain=4

DNLMin

-1

-2

-3

-4

-5

BipolarZeroError(mV)

4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 A VV = A (V)-

DD S S

DV =IOV =4.5V

DD DD

V =2.048V

REF

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

BipolarGainError(mV)

4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 AV = AV (V)

DD S S

DVDD=IOVDD=4.5V

V =2.048V

REF

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

BipolarZeroError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+18V AV = -SS18V

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

BipolarZeroError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+18V AV = -SS18V

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

DAC8718

www.ti.com

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR vs AVDDAND AV

Figure 21. Figure 22.

BIPOLAR ZERO ERROR BIPOLAR GAIN ERROR

vs AVDDAND AV

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

vs AVDDAND AV

Figure 23. Figure 24.

BIPOLAR ZERO ERROR BIPOLAR ZERO ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 25. Figure 26.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

-5

BipolarGainError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+18V AV = -SS18V

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

BipolarGainError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+18V AV = -SS18V

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

BipolarZeroError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

BipolarZeroError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

Gain=4

BipolarGainError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

BipolarGainError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

Gain=4

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

BIPOLAR GAIN ERROR BIPOLAR GAIN ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 27. Figure 28.

BIPOLAR ZERO ERROR BIPOLAR ZERO ERROR

vs TEMPERATURE vs TEMPERATURE

www.ti.com

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 29. Figure 30.

BIPOLAR GAIN ERROR BIPOLAR GAIN ERROR

vs TEMPERATURE vs TEMPERATURE

Figure 31. Figure 32.

Product Folder Link(s): DAC8718

AnalogPower-SupplyCurrent(mA)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

AVDD

-I

AVSS

AnalogPower-SupplyCurrent(mA)

-I

AVSS

AVDD

1.0 5.55.04.54.03.53.01.5 2.0

V (V)

REF

2.5

AllDACsLoadedwithMidscaleCode

AVDD=+18V

A =VSS-18V

AnalogPower-SupplyCurrent(mA)

8192

65536573444915240960327682457616384

DigitalInputCode

AllDACsLoadedwithSameCode

AVDD

-I

AVSS

250

200

150

100

DigitalPower-SupplyCurrent( A)m

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

LogicInputVoltage(V)

SweepFrom

5.5Vto0V

SweepFrom 0Vto5.5V

OneDigitalInputSwept,AllOthersatGNDorIOV

DV (mV)

OUT

-15 -9 -3 3 9-12 -6 0 6 12 15 CurrentOutputI (mA)

OUT

--6

FFFFh C000h 8000h 4000h 0000h

2000

1800

1600

1400

1200

1000

800

600

400

200

Noise(nV/ )ÖHz

1 100k10k1k10010

Frequency(Hz)

DACLoadedwithMidscaleCode

Gain=6

Gain=4

DAC8718

www.ti.com

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

ANALOG POWER-SUPPLY CURRENT ANALOG POWER-SUPPLY CURRENT

vs TEMPERATURE vs REFERENCE VOLTAGE

Figure 33. Figure 34.

ANALOG POWER-SUPPLY CURRENT DIGITAL POWER-SUPPLY CURRENT

vs DIGITAL INPUT CODE vs LOGIC INPUT VOLTAGE

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 35. Figure 36.

DELTA OUTPUT VOLTAGE DAC OUTPUT NOISE DENSITY

vs SOURCE AND SINK CURRENTS vs FREQUENCY

Figure 37. Figure 38.

Product Folder Link(s): DAC8718

Time(10 s/div)m

1LSB/div

5V/div

TriggerPulse: LDAC

FromCode:0000h ToCode: Load:10k ||240pF

FFFFh

Small-SignalError

Large-SignalV

OUT

Time(10 s/div)m

1LSB/div

5V/div

TriggerPulse: LDAC

FromCode:FFFFh ToCode: Load:10k ||240pF

0000h

5V/div

Large-SignalV

OUT

Small-SignalError

Time(10 s/div)m

1LSB/div

5V/div

FromCode:4000h ToCode: Load:10k ||240pF

C000h

5V/div

Large-SignalV

OUT

Small-SignalError

TriggerPulse: LDAC

Time(10 s/div)m

1LSB/div

5V/div

FromCode:C000h ToCode: Load:10k ||240pF

4000h

5V/div

TriggerPulse: LDAC

Large-SignalV

OUT

Small-SignalError

Time(2 s/div)m

V (1mV/div)

OUT

GlitchImpulse

TriggerPulse5V/div

FromCode:7FFFh

ToCode:

Channel0asExample

8000h

Load:10k ||200pFW

Time(2 s/div)m

V (1mV/div)

OUT

FromCode:8000h

ToCode:

Channel0asExample

Load:10k ||200pF

7FFFh

TriggerPulse5V/div

GlitchImpulse

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

SETTLING TIME SETTLING TIME

–15V TO +15V TRANSITION +15V TO –15V TRANSITION

Figure 39. Figure 40.

SETTLING TIME SETTLING TIME

1/4 TO 3/4 FULL-SCALE TRANSITION 3/4 TO 1/4 FULL-SCALE TRANSITION

www.ti.com

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 41. Figure 42.

GLITCH ENERGY GLITCH ENERGY

1 LSB STEP, RISING EDGE 1 LSB STEP, FALLING EDGE

Figure 43. Figure 44.

Product Folder Link(s): DAC8718

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

BipolarZeroError(LSB)

Population(%)

-15

-13

-11

-9

-7

-5

-3

-1

BipolarZeroError(LSB)

Gain=4

Population(%)

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

BipolarGainError(LSB)

Population(%)

-15

-13

-11

-9

-7

-5

-3

-1

BipolarGainError(LSB)

Gain=4

Population(%)

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

5.0

5.2

5.4

5.6

5.8

6.0

AI (mA)

Population(%)

-4.0

-3.6

-3.2

-2.8

-2.4

-2.0

-1.6

-1.2

-0.8

AI (mA)

Population(%)

DAC8718

www.ti.com

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

BIPOLAR ZERO ERROR BIPOLAR ZERO ERROR

HISTOGRAM HISTOGRAM

Figure 45. Figure 46.

BIPOLAR GAIN ERROR BIPOLAR GAIN ERROR

HISTOGRAM HISTOGRAM

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Figure 47. Figure 48.

NEGATIVE ANALOG POWER SUPPLY POSITIVE ANALOG POWER SUPPLY

HISTOGRAM HISTOGRAM

Figure 49. Figure 50.

Product Folder Link(s): DAC8718

Time(2 s/div)m

DACCode=8000h

NoLoad Gain=6

Channel0asExample

V (5 V/div)m

OUT

Time(2 s/div)m

DACCode=8000h

NoLoad Gain=4

Channel0asExample

V (5 V/div)m

OUT

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Bipolar (continued)

At TA= 25°C, AVDD= 16.5V, AVSS= –16.5V, V

DAC OUTPUT NOISE DAC OUTPUT NOISE

0.1Hz TO 10Hz 0.1Hz TO 10Hz

Figure 51. Figure 52.

www.ti.com

= IOVDD= DVDD= 5V, gain = 6, data format=USB, unless otherwise noted.

REF

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

AllEightChannelsShown

8192

65536573444915240960327682457616384

DigitalInputCode

AllEightChannelsShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

Gain=4

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

Gain=4

DAC8718

www.ti.com

TYPICAL CHARACTERISTICS: Unipolar

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (All 8 Channels) vs DIGITAL INPUT CODE (All 8 Channels)

Figure 53. Figure 54.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+25°C) vs DIGITAL INPUT CODE (+25°C)

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 55. Figure 56.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

-1

-2

-3

-4

INLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

8192

65536573444915240960327682457616384

DigitalInputCode

TypicalChannelShown

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (–40°C) vs DIGITAL INPUT CODE (–40°C)

Figure 57. Figure 58.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+25°C) vs DIGITAL INPUT CODE (+25°C)

www.ti.com

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 59. Figure 60.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs DIGITAL INPUT CODE (+105°C) vs DIGITAL INPUT CODE (+105°C)

Figure 61. Figure 62.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature( C)°

INLMax

INLMin

DNLError(LSB)

-55

-40 -25 -10

20 35 50 65 80 95 110 125

Temperature(°C)

DNLMin

DNLMax

1.0

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

-1

-2

-3

-4

INLError(LSB)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

INLMax

Gain=4

INLMin

DNLError(LSB)

-55

-40 -25 -10

20 35 50 65 80 95 110 125

Temperature(°C)

1.0

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

DNLMin

DNLMax

Gain=4

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

1.0 5.55.04.54.03.53.01.5 2.0 V (V)

REF

2.5

AVDD=+36V

DNLMax

DNLMin

-1

-2

-3

-4

INLError(LSB)

1.0 5.55.04.54.03.53.01.5 2.0 V (V)

REF

2.5

INLMax

INLMin

AVDD=+36V

DAC8718

www.ti.com

TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE vs TEMPERATURE

Figure 63. Figure 64.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE vs TEMPERATURE

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 65. Figure 66.

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 67. Figure 68.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

INLError(LSB)

9 12 15 18 21 24 27 30 33 36

AV (V)

INLMax

INLMin

1.0

0.8

0.6

0.4

0.2

-0.2

-0.4

-0.6

-0.8

-1.0

DNLError(LSB)

9 12 15 18 21 24 27 30 33 36

AV (V)

DNLMax

DNLMin

-1

-2

-3

-4

-5

Zero-ScaleError(mV)

9 12 15 18 21 24 27 30 33 36

+AV (V)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

AllDACSLoadedwith0100h

Gain=4

V =2.048V

REF

-1

-2

-3

-4

-5

UnipolarGainError(mV)

9 12 15 18 21 24 27 30 33 36

+AV (V)

DVDD=IOVDD=4.5V

V =2.048V

REF

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

Zero-ScaleError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

AllDACSLoadedwith0100h

AV =+36V

-1

-2

-3

-4

-5

Zero-ScaleError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

AllDACSLoadedwith0100h

Gain=4

AV =+36V

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs ANALOG SUPPLY VOLTAGE vs ANALOG SUPPLY VOLTAGE

Figure 69. Figure 70.

ZERO-SCALE ERROR UNIPOLAR GAIN ERROR

vs ANALOG SUPPLY VOLTAGE vs ANALOG SUPPLY VOLTAGE

www.ti.com

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 71. Figure 72.

ZERO-SCALE ERROR ZERO-SCALE ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 73. Figure 74.

Product Folder Link(s): DAC8718

-1

-2

-3

-4

-5

UnipolarGainError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+36V

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

-1

-2

-3

-4

-5

UnipolarGainError(mV)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD=+36V

Gain=4

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

Zero-ScaleError(mV)

-55

-40 -25 -10

20 35 50 65 80 95 110 125

Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

AllDACSLoadedwith0100h

Zero-ScaleError(mV)

-55

-40 -25 -10

20 35 50 65 80 95 110 125

Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

AllDACSLoadedwith0100h

Gain=4

UnipolarGainError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

UnipolarGainError(mV)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

Ch0 Ch1 Ch2 Ch3

Ch4 Ch5 Ch6 Ch7

Gain=4

DAC8718

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TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

UNIPOLAR GAIN ERROR UNIPOLAR GAIN ERROR

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 75. Figure 76.

ZERO-SCALE ERROR ZERO-SCALE ERROR

vs TEMPERATURE vs TEMPERATURE

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 77. Figure 78.

UNIPOLAR GAIN ERROR UNIPOLAR GAIN ERROR

vs TEMPERATURE vs TEMPERATURE

Figure 79. Figure 80.

Product Folder Link(s): DAC8718

AnalogPower-SupplyCurrent(mA)

-55 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature(°C)

AnalogPower-SupplyCurrent(mA)

1.51.0 5.55.04.54.03.53.02.52.0 V (V)

REF

AVDD

AllDACsLoadedwithMidscaleCode

AVDD=+36V

AnalogPower-SupplyCurrent(mA)

8192

65536573444915240960327682457616384

DigitalInputCode

AllDACsLoadedwithSameCode

AVDD

30.5

30.0

29.5

29.0

28.5

28.0

27.5

OutputVoltageV (V)

OUT

0 3 6 9 12 15

I (mA)

SOURCE

FFFFh FF00h FE00h FC00h F800h

2.5

2.0

1.5

1.0

0.5

OutputVoltageV (V)

OUT

-15 -12 -9 -6 -3 0

I (mA)

SINK

0000h 0100h 0200h 0400h 0800h

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

ANALOG POWER-SUPPLY CURRENT ANALOG POWER-SUPPLY CURRENT

vs TEMPERATURE vs REFERENCE VOLTAGE

Figure 81. Figure 82.

www.ti.com

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

ANALOG POWER-SUPPLY CURRENT

vs DIGITAL INPUT CODE

vs SOURCE CURRENT CAPABILITY vs SINK CURRENT CAPABILITY

OUTPUT VOLTAGE OUTPUT VOLTAGE

Figure 84. Figure 85.

Figure 83.

Product Folder Link(s): DAC8718

Time(10 s/div)m

1LSB/div

5V/div

TriggerPulse: LDAC

FromCode:0100h ToCode: Load:10k ||240pF

FFFFh

Large-SignalV

OUT

Small-SignalError

Time(10 s/div)m

1LSB/div

5V/div

TriggerPulse: LDAC

FromCode:FFFFh

ToCode:

Load:10k ||240pF

0100h

Large-SignalV

OUT

Small-SignalError

Time(10 s/div)m

1LSB/div

5V/div

FromCode:4000h ToCode: Load:10k ||240pF

C000h

5V/div

TriggerPulse: LDAC

Large-SignalV

OUT

Small-SignalError

Time(10 s/div)m

1LSB/div

5V/div

FromCode:C000h ToCode: Load:10k ||240pF

4000h

5V/div

TriggerPulse: LDAC

Large-SignalV

OUT

Small-SignalError

Time(2 s/div)m

V (1mV/div)

OUT

TriggerPulse5V/div

GlitchImpulse

FromCode:7FFFh

ToCode:

Channel0asExample

8000h

Load:10k ||200pFW

Time(2 s/div)m

V (1mV/div)

OUT

GlitchImpulse

TriggerPulse5V/div

FromCode:8000h

ToCode:

Channel0asExample

7FFFh

Load:10k ||200pFW

DAC8718

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TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

SETTLING TIME SETTLING TIME

0V TO 30V TRANSITION 30V TO 0V TRANSITION

Figure 86. Figure 87.

SETTLING TIME SETTLING TIME

1/4 TO 3/4 TRANSITION 3/4 TO 1/4 TRANSITION

SBAS467A –MAY 2009–REVISED DECEMBER 2009

= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 88. Figure 89.

GLITCH ENERGY GLITCH ENERGY

1 LSB STEP, RISING EDGE 1 LSB STEP, FALLING EDGE

Figure 90. Figure 91.

Product Folder Link(s): DAC8718

-10

-9-8-7-6-5-4-3

-2

-1

Zero-ScaleError(LSB)

Population(%)

Code=0100h

-15

-13

-11

-9

-7

-5

-3

-1

Zero-ScaleError(LSB)

Population(%)

Code=0100h

Gain=4

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

UnipolarGainError(LSB)

Population(%)

-15

-13

-11

-9

-7

-5

-3

-1

UnipolarGainError(LSB)

Gain=4

Population(%)

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

AI (mA)

Population(%)

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

TYPICAL CHARACTERISTICS: Unipolar (continued)

At TA= 25°C, AVDD= 32V, AVSS= 0V, V

ZERO-SCALE ERROR ZERO-SCALE ERROR

HISTOGRAM HISTOGRAM

Figure 92. Figure 93.

UNIPOLAR GAIN ERROR UNIPOLAR GAIN ERROR

HISTOGRAM HISTOGRAM

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= 5V, IOVDD= DVDD= 5V, gain=6, and data format=USB, unless otherwise noted.

REF

Figure 94. Figure 95.

ANALOG POWER-SUPPLY CURRENT

HISTOGRAM

Figure 96.

Product Folder Link(s): DAC8718

REF-x

ToOutput Amplifier

DAC8718

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

THEORY OF OPERATION

GENERAL DESCRIPTION

The DAC8718 contains eight DAC channels and eight output amplifiers in a single package. Each channel consists of a resistor-string DAC followed by an output buffer amplifier. The resistor-string section is simply a string of resistors, each with a value of R, from REF-x to AGND, as shown in Figure 97. This type of architecture provides DAC monotonicity. The 16-bit binary digital code loaded to the DAC latch determines at which node on the string the voltage is tapped off before being fed into the output amplifier. The output amplifier multiplies the DAC output voltage by a gain of six or four. Using a gain of 6 and power supplies allowing for at least 0.5V headroom, the output span is 9V with a 1.5V reference, 18V with a 3V reference, and 30V with a 5V reference.

Figure 97. Resistor String

CHANNEL GROUPS

The eight DAC channels and two Offset DACs are arranged into two groups (A and B) with four channels and one Offset DAC per group. Group A consists of DAC-0, DAC-1, DAC-2, DAC-3, and Offset DAC-A. Group B consists of DAC-4, DAC-5, DAC-6, DAC-7, and Offset DAC-B. Group A derives its reference voltage from REF-A, and Group B derives its reference voltage from REF-B.

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USER-CALIBRATION FOR ZERO-CODE ERROR AND GAIN ERROR

The DAC8718 implements a digital user-calibration function that allows for trimming gain and zero errors on the entire signal chain. This function can eliminate the need for external adjustment circuits. Each DAC channel has a Zero Register and Gain Register. Using the correction engine, the data from the Input Data Register are operated on by a digital adder and multiplier controlled by the contents of the Zero and Gain registers, respectively. The calibrated DAC data are then stored in the DAC Data Register where they are finally transferred into the DAC latch and set the DAC output. Each time the data are written to the Input Data Register (or to the Gain or Zero registers), the data in the Input Data Register are corrected, and the results automatically transferred to the DAC Data Register.

The range of the gain adjustment coefficient is 0.5 to 1.5. The range of the zero adjustment is –32768 LSB to +32767 LSB, or ±50% of full scale.

There is only one correction engine in the DAC8718, which is shared among all channels. If the user-calibration function is not needed, the correction engine can be turned off. Setting the SCE bit in the

Configuration Register to '0' turns off the correction engine. Setting SCE to '1' enables the correction engine. When SCE = '0', the data are directly transferred to the DAC Data Register. In this case, writing to the Gain Register or Zero Register updates the Gain and Zero registers but does not start a math engine calculation. Reading these registers returns the written values.

Product Folder Link(s): DAC8718

V =

OUT

V Gain

REF

´ ´

INPUT_CODE

65536

OFFSETDAC_CODE

65536

V (Gain 1)- ´ -

REF

V =

OUT

V Gain

REF

´ ´

DAC_DATA_CODE

65536

OFFSETDAC_CODE

65536

V (Gain 1)- ´ -

REF

DAC_DATA_CODE =

INPUT_CODE (USER_GAIN+2

´ )

+USER_ZERO

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ANALOG OUTPUTS (V

OUT

-0 to V

-7, with reference to the ground of REF-x)

OUT

SBAS467A –MAY 2009–REVISED DECEMBER 2009

When the correction engine is off (SCE = '0'):

(1)

SPACE

When the correction engine is on (SCE = '1'):

(2)

SPACE

Where:

Gain = the DAC gain defined by the GAIN bit in the Configuration Register. INPUT_CODE = data written into the Input Data Register (SCE = '1') or the DAC Data Register (SCE = '0'). OFFSETDAC_CODE = the data written into the Offset DAC Register. USER_GAIN = the code of the Gain Register. USER_ZERO = the code of the Zero Register.

For single-supply operation, the OFFSET-A pin must be connected to the AGND-A pin and the OFFSET-B pin must be connected to the AGND-B pin through low-impedance connections (see the Layout section for details). Offset DAC-A and Offset DAC-B are in a power-down state.

For dual-supply operation, the OFFSET-A and OFFSET-B default codes for a gain of 6 are 39322 with a ±10 LSB variation, depending on the linearity of the Offset DACs. The default code for a gain of 4 is 43691 with a ±10 LSB variation. The default codes of OFFSET-A and OFFSET-B are independently factory trimmed for both gains of 6 and 4.

The power-on default value of the Gain Register is 32768, and the default value of the Zero Register is '0'. The DAC input registers are set to a default value of 0000h.

Note that the maximum output voltage must not be greater than (AVDD– 0.5V) and the minimum output voltage must not be less than (AVSS+ 0.5V); otherwise, the output may be saturated.

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INPUT DATA FORMAT

The USB/BTC pin defines the input data format and the Offset DAC format. When this pin is connected to DGND, the Input DAC data and Offset DAC data are straight binary, as shown in Table 1 and Table 3. When this pin is connected to IOVDD, the Input DAC data and Offset DAC data are in twos complement format, as shown in

Table 2 and Table 4.

Table 1. Bipolar Output vs Straight Binary Code Using Dual Power Supplies with Gain = 6

USB CODE NOMINAL OUTPUT DESCRIPTION

FFFFh +3 × V

••• ••• ••• ••• ••• ••• 8001h +3 × V 8000h 0 Zero

7FFFh –3 × V

••• ••• ••• ••• ••• ••• 0000h –3 × V

Table 2. Bipolar Output vs Twos Complement Code Using Dual Power Supplies with Gain = 6

BTC CODE NOMINAL OUTPUT DESCRIPTION

7FFFh +3 × V

••• ••• ••• ••• ••• ••• 0001h +3 × V 0000h 0 Zero

FFFFh –3 × V

••• ••• ••• ••• ••• ••• 8000h –3 × V

× (32767/32768) +Full-Scale – 1 LSB

REF

× (1/32768) +1 LSB

REF

× (1/32768) –1 LSB

REF

× (32768/32768) –Full-Scale

REF

× (32767/32768) +Full-Scale – 1 LSB

REF

× (1/32768) +1 LSB

REF

× (1/32768) –1 LSB

REF

× (32768/32768) –Full-Scale

REF

Table 3. Unipolar Output vs Straight Binary Code Using Single Power Supply with Gain = 6

USB CODE NOMINAL OUTPUT DESCRIPTION

FFFFh +6 × V

× (65535/65536) +Full-Scale – 1 LSB

REF

••• ••• ••• ••• ••• ••• 8001h +6 × V 8000h +6 × V

7FFFh +6 × V

× (32769/65536) Midscale + 1 LSB

REF

× (32768/65536) Midscale

REF

× (32767/65536) Midscale – 1 LSB

REF

••• ••• ••• ••• ••• ••• 0000h 0 0

Table 4. Unipolar Output vs Twos Complement Code Using Single Power Supply with Gain = 6

BTC CODE NOMINAL OUTPUT DESCRIPTION

7FFFh +6 × V

× (65535/65536) +Full-Scale – 1 LSB

REF

••• ••• ••• ••• ••• ••• 0001h +6 × V 0000h +6 × V

FFFFh +6 × V

× (32769/65536) Midscale + 1 LSB

REF

× (32768/65536) Midscale

REF

× (32767/65536) Midscale – 1 LSB

REF

••• ••• ••• ••• ••• ••• 8000h 0 0

The data written to the Gain Register are always in straight binary, data to the Zero Register are in twos complement, and data to all other control registers are as specified in the definitions, regardless of the USB/BTC pin status.

In reading operation, the read-back data are in the same format as written.

Product Folder Link(s): DAC8718

V = V (Gain 1)

OUT REF

- ´ - ´

OFFSETDAC_CODE

65536

DAC8718

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

OFFSET DACS

There are two 16-bit Offset DACs: one for Group A, and one for Group B. The Offset DACs allow the entire output curve of the associated DAC groups to be shifted by introducing a programmable offset. This offset allows for asymmetric bipolar operation of the DACs or unipolar operation with bipolar supplies. Thus, subject to the limitations of headroom, it is possible to set the output range of Group A and/or Group B to be unipolar positive, unipolar negative, symmetrical bipolar, or asymmetrical bipolar, as shown in Table 5 and Table 6. Increasing the digital input codes for the offset DAC shifts the outputs of the associated channels in the negative direction. The default codes for the Offset DACs in the DAC8718 are factory trimmed to provide optimal offset and gain performance for the default output range and span of symmetric bipolar operation. When the output range is adjusted by changing the value of the Offset DAC, an extra offset is introduced as a result of the linearity and offset errors of the Offset DAC. Therefore, the actual shift in the output span may vary slightly from the ideal calculations. For optimal offset and gain performance in the default symmetric bipolar operation, the Offset DAC input codes should not be changed from the default power-on values. The maximum allowable offset depends on the reference and the power supply. If INPUT_CODE from Equation 1 or DAC_DATA_CODE from Equation 2 is set to 0, then these equations simplify to Equation 3:

(3)

This equation shows the transfer function of the Offset DAC to the output of the DAC channels. In any case, the analog output must not go beyond the specified range shown in the Analog Outputs section. After power-on or reset, the Offset DAC is set to the value defined by the selected data format and the selected analog output voltage. If the DAC gain setting is changed, the offset DAC code is reset to the default value corresponding to the new DAC gain setting. Refer to the Power-On Reset and Hardware Reset sections for details.

For single-supply operation (AVSS= 0V), the Offset DAC is turned off, and the output amplifier is in a Hi-Z state. The OFFSET-x pin must be connected to the AGND-x pin through a low-impedance connection (see the Layout section for details). For dual-supply operation, this pin provides the output of the Offset DAC. The OFFSET-x pin is not intended to drive an external load. See Figure 98 for the internal Offset DAC and output amplifier configuration.

Table 5. Example of Offset DAC Codes and Output Ranges with Gain = 6 and V

OFFSET DAC OFFSET DAC DAC CHANNELS MFS

CODE VOLTAGE VOLTAGE VOLTAGE

(2)

999Ah

0000h 0V 0V +30V – 1 LSB

FFFFh ~5.0V –25V +5V – 1 LSB

6666h ~2.0V –10V +20V – 1 LSB

CCCDh ~4.0V –20V +10V – 1 LSB

(1) MFS = minus full-scale; PFS = plus full-scale. (2) This is the default code for symmetric bipolar operation; actual codes may vary ±10 LSB. Codes are in straight binary format.

3.0V –15V +15V – 1 LSB

(1)

DAC CHANNELS PFS

Table 6. Example of Offset DAC Codes and Output Ranges with Gain = 4 and V

OFFSET DAC OFFSET DAC DAC CHANNELS MFS

CODE VOLTAGE VOLTAGE VOLTAGE

(2)

AAABh

0000h 0V 0V +20V – 1 LSB

FFFFh ~5.0V –15V +5V – 1 LSB

5555h ~1.666V –5V +15V – 1 LSB 8000h 2.5V –7.5V +12.5V – 1 LSB

D555h ~4.1666V –12.5V +7.5V – 1 LSB

(1) MFS = minus full-scale; PFS = plus full-scale. (2) This is the default code for symmetric bipolar operation; actual codes may vary ±10 LSB. Codes are in straight binary format.

~3.33333V –10V +10V – 1 LSB

(1)

DAC CHANNELS PFS

REF

= 5V

(1)

Product Folder Link(s): DAC8718

DAC

Channel

Offset

DAC

OFF

AGND-x

OUT

OFFSET

V =GAINxV (GAIN 1)xV- -

OUT 1 OFF

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

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Figure 98. Output Amplifier and Offset DAC

OUTPUT AMPLIFIERS

The output amplifiers can swing to 0.5V below the positive supply and 0.5V above the negative supply. This condition limits how much the output can be offset for a given reference voltage. The maximum range of the output for ±17V power and a +5.5V reference is –16.5V to +16.5V for gain = 6.

Each output amplifier is implemented with individual over-current protection. The amplifier is clamped at 8mA, even if the output current goes over 8mA.

Product Folder Link(s): DAC8718

BitGPIO-n(whenwriting)

BitGPIO-n(whenreading)

Enable

GPIO-n

DAC8718

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

GENERAL-PURPOSE INPUT/OUTPUT PINS (GPIO-0 to GPIO-2)

The GPIO pins are general-purpose, bidirectional, digital input/outputs, as shown in Figure 99. When a GPIO pin acts as an output, the pin status is determined by the corresponding GPIO bit in the GPIO Register. The pin output is high-impedance when the GPIO bit is set to '1', and is logic low when the GPIO bit is cleared to '0'. Note that a pull-up resistor to IOVDDis required when using a GPIO pin as an output. When a GPIO pin acts as an input, the digital value on the pin is acquired by reading the corresponding GPIO bit. After power-on reset, or any forced hardware or software reset, the GPIO bits are set to '1', and the GPIO pins are in a high-impedance state. If not used, the GPIO pins must be tied to either DGND or to IOVDDthrough a pull-up resistor. Leaving the GPIO pins floating can cause high IOVDDsupply currents.

Figure 99. GPIO-n Pin

ANALOG OUTPUT PIN (CLR)

The CLR pin is an active low input that should be high for normal operation. When this pin is in logic '0', all V outputs connect to AGND-x through internal 15kΩ resistors and are cleared to 0V, and the output buffer is in a Hi-Z state. While CLR is low, all LDAC pulses are ignored. When CLR is taken high again while the LDAC is high, the DAC outputs remain cleared until LDAC is taken low. However, if LDAC is tied low, taking CLR back to high sets the DAC output to the level defined by the value of the DAC latch. The contents of the Zero Registers, Gain Registers, Input Data Registers, DAC Data Registers, and DAC latches are not affected by taking CLR low.

OUT

Product Folder Link(s): DAC8718

DAC8718

SBAS467A –MAY 2009–REVISED DECEMBER 2009

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POWER-ON RESET

The DAC8718 contains a power-on reset circuit that controls the output during power-on and power down. This feature is useful in applications where the known state of the DAC output during power-on is important. The Offset DAC Registers, DAC Data Registers, and DAC latches are loaded with the value defined by the RSTSEL pin, as shown in Table 7. The Gain Registers and Zero Registers are loaded with default values. The Input Data Register is reset to 0000h, independent of the RSTSEL state.

Table 7. Bipolar Output Reset Values for Dual Power-Supply Operation

VALUE OF DAC VALUE OF OFFSET

RSTSEL PIN USB/BTC PIN INPUT FORMAT AND DAC LATCH FOR GAIN = 6

DGND DGND Straight Binary 0000h 999Ah –Full-Scale

IOV

DGND IOV

IOV

(1) Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary

no more than ±10 LSB from the nominal number listed in this table.

DGND Straight Binary 8000h 999Ah 0 V

Twos Complement 8000h 199Ah –Full-Scale Twos Complement 0000h 199Ah 0 V

IOV

DD DD

DATA REGISTER DAC REGISTER

In single-supply operation, the Offset DAC is turned off and the output is unipolar. The power-on reset is defined as shown in Table 8.

Table 8. Unipolar Output Reset Values for Single Power-Supply Operation

VALUE OF DAC DATA

RSTSEL PIN USB/BTC PIN INPUT FORMAT LATCH V

DGND DGND Straight Binary 0000h 0 V

IOV

DGND IOV

IOV

DGND Straight Binary 8000h Midscale

Twos Complement 8000h 0 V Twos Complement 0000h Midscale

IOV

DD DD

(1)

OUT

HARDWARE RESET

When the RST pin is low, the device is in hardware reset. All the analog outputs (V registers, and the DAC latches are set to the reset values defined by the RSTSEL pin as shown in Table 7 and

Table 8. In addition, the Gain and Zero Registers are loaded with default values, communication is disabled, and

the signals on CS and SDI are ignored (note that SDO is in a high-impedance state). The Input Data Register is reset to 0000h, independent of the RSTSEL state. On the rising edge of RST, the analog outputs (V V

-7) maintain the reset value as defined by the RSTSEL pin until a new value is programmed. After RST

OUT

goes high, the serial interface returns to normal operation. CS must be set to a logic high whenever RST is used.

OUT

-0 to V

-7), the DAC

OUT

-0 to

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

UPDATING THE DAC OUTPUTS

Depending on the status of both CS and LDAC, and after data have been transferred into the DAC Data registers, the DAC outputs can be updated either in asynchronous mode or synchronous mode. This update mode is established at power-on. If asynchronous mode is desired, the LDAC pin must be permanently tied low before power is applied to the device. If synchronous mode is desired, LDAC must be logic high before and during power-on.

The DAC8718 updates a DAC latch only if it has been accessed since the last time LDAC was brought low or if the LD bit is set to '1', thereby eliminating any unnecessary glitch. Any DAC channels that were not accessed are not loaded again. When the DAC latch is updated, the corresponding output changes to the new level immediately.

Asynchronous Mode

In this mode, the LDAC pin is set low at power-up. This action places the DAC8718 into Asynchronous mode, and the LD bit and LDAC signal are ignored. When the correction engine is off (SCE bit = '0'), the DAC Data Registers and DAC latches are updated immediately when CS goes high. When the correction engine is on (SCE bit = '1'), each DAC latch is updated individually when the correction engine updates the corresponding DAC Data Register.

Synchronous Mode

To use this mode, set LDAC high before CS goes low, and then take LDAC low or set the LD bit to '1' after CS goes high. If LDAC goes low or if the LD bit is set to '1' when SCE = '0', all DAC latches are updated simultaneously. If LDAC goes low or if the LD bit is set to '1' when SCE = '1', all DAC latches are updated simultaneously after the correction engine has updated the corresponding DAC register.

In this mode, when LDAC stays high, the DAC latch is not updated; therefore, the DAC output does not change. The DAC latch is updated by taking LDAC low (or by setting the LD bit in the Configuration Register to '1') any time after the delay of t9from the rising edge of CS. If the timing requirement of t9is not satisfied, invalid data are loaded. Refer to the Timing Diagrams and the Configuration Register (Table 11) for details.

Product Folder Link(s): DAC8718

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SBAS467A –MAY 2009–REVISED DECEMBER 2009

MONITOR OUTPUT PIN (V

The V

pin is the channel monitor output. It can be either high-impedance or monitor any one of the DAC

MON

)

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outputs, auxiliary analog inputs, offset DAC outputs, or reference buffer outputs. The channel monitor function consists of an analog multiplexer addressed via the serial interface, allowing any channel output, reference buffer output, auxiliary analog inputs, or offset DAC output to be routed to the V

pin for monitoring using an external

MON

ADC. The monitor function is controlled by the Monitor Register, which allows the monitor output to be enabled or disabled. When disabled, the monitor output is high-impedance; therefore, several monitor outputs may be connected in parallel with only one enabled at a time.

Note that the multiplexer is implemented as a series of analog switches. Care should be taken to ensure the maximum current from the V conceivably cause a large amount of current to flow from the input of the multiplexer (that is, from V output of the multiplexer (V

MON

pin must not be greater than the given specification because this could

MON

OUT

). Refer to the Monitor Register section and Table 12 for more details.

-X) to the

ANALOG INPUT PINS (AIN-0 and AIN-1)

Pins AIN-0 and AIN-1 are two analog inputs that directly connect to the analog mux of the analog monitor output. When AIN-0 or AIN-1 is accessed, it is routed via the mux to the V

pin. Thus, one external ADC channel can

MON

monitor eight DACs plus two extra external analog signals, AIN-0 and AIN-1.

POWER-DOWN MODE

The DAC8718 is implemented with a power-down function to reduce power consumption. Either the entire device or each individual group can be put into power-down mode. If the proper power-down bit (PD-x) in the Configuration Register is set to '1', the individual group is put into power down mode. During power-down mode, the analog outputs (V buffer is in Hi-Z status. When the entire device is in power-down, the bus interface remains active in order to continue communication and receive commands from the host controller, but all other circuits are powered down. The host controller can wake the device from power-down mode and return to normal operation by clearing the PD-x bit; it takes 200μs or less for recovery to complete.

OUT

-0 to V

-7) connect to AGND-X through an internal 15kΩ resistor, and the output

OUT

POWER-ON RESET SEQUENCING

The DAC8718 permanently latches the status of some of the digital pins at power-on. These digital levels should be well-defined before or while the digital supply voltages are applied. Therefore, it is advised to have a pull up resistor to IOVDDfor the digital initialization pins (LDAC, CLR, RST, CS, and RSTSEL) to ensure that these levels are set correctly while the digital supplies are raised.

For proper power-on initialization of the device, IOVDDand the digital pins must be applied before or at the same time as DVDD. If possible, it is preferred that IOVDDand DVDDcan be connected together in order to simplify the supply sequencing requirements. Pull-up resistors should go to either supply. AVDDshould be applied after the digital supplies (IOVDDand DVDD) and digital initialization pins (LDAC, CLR, RST, CS, and RSTSEL). AVSScan be applied at the same time as or after AVDD. The REF-x pins must be applied last.

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SERIAL INTERFACE

The DAC8718 is controlled over a versatile, three-wire serial interface that operates at clock rates of up to 50MHz and is compatible with SPI, QSPI™, Microwire™, and DSP™ standards.

SPI Shift Register

The SPI Shift Register is 24 bits wide. Data are loaded into the device MSB first as a 24-bit word under the control of the serial clock input, SCLK. The SPI Shift Register consists of a read/write bit, five register address bits, 16 data bits, and two reserve bits for future devices, as shown in Table 9. The falling edge of CS starts the communication cycle. The data are latched into the SPI Shift Register on the falling edge of SCLK while CS is low. When CS is high, the SCLK and SDI signals are blocked and the SDO pin is in a high-impedance state. The contents of the SPI shifter register are decoded and transferred to the proper internal registers on the rising edge of CS. The timing for this operation is shown in the Timing Diagrams section.

The serial interface works with both a continuous and non-continuous serial clock. A continuous SCLK source can only be used if CS is held low for the correct number of clock cycles. In gated clock mode, a burst clock containing the exact number of clock cycles must be used and CS must be taken high after the final clock in order to latch the data.

The serial interface requires CS to be logic high during the power-on sequencing; therefore, it is advised to have a pullup resistor to IOVDDon the CS pin. Refer to the Power-On Reset Sequencing section for further details.

Stand-Alone Operation

The serial clock can be a continuous or a gated clock. The first falling edge of CS starts the operation cycle. Exactly 24 falling clock edges must be applied before CS is brought back high again. If CS is brought high before the 24th falling SCLK edge, then the data written are not transferred into the internal registers. If more than 24 falling SCLK edges are applied before CS is brought high, then the last 24 bits are used. The device internal registers are updated from the Shift Register on the rising edge of CS. In order for another serial transfer to take place, CS must be brought low again.

When the data have been transferred into the chosen register of the addressed DAC, all DAC latches and analog outputs can be updated by taking LDAC low.

Daisy-Chain Operation

For systems that contain more than one device, the SDO pin can be used to daisy-chain multiple devices together. Daisy-chain operation can be useful in system diagnostics and in reducing the number of serial interface lines. Note that before daisy-chain operation can begin, the SDO pin must be enabled by setting the SDO disable bit (DSDO) in the Configuration Register to '0'; this bit is cleared by default.

The DAC8718 provides two modes for daisy-chain operation: normal and sleep. The SLEEP bit in the SPI Mode register determines which mode is used.

In Normal mode (SLEEP bit = '0'), the data clocked into the SDI pin are transferred into the Shift Register. The first falling edge of CS starts the operating cycle. SCLK is continuously applied to the SPI Shift Register when CS is low. If more than 24 clock pulses are applied, the data ripple out of the Shift Register and appear on the SDO line. These data are clocked out on the rising edge of SCLK and are valid on the falling edge. By connecting the SDO pin of the first device to the SDI input of the next device in the chain, a multiple-device interface is constructed. Each device in the system requires 24 clock pulses. Therefore, the total number of clock cycles must equal 24 × N, where N is the total number of DAC8718s in the chain. When the serial transfer to all devices is complete, CS is taken high. This action latches the data from the SPI Shift Registers to the device internal registers for each device in the daisy-chain, and prevents any further data from being clocked in. The serial clock can be a continuous or a gated clock. Note that a continuous SCLK source can only be used if CS is held low for the correct number of clock cycles. For gated clock mode, a burst clock containing the exact number of clock cycles must be used and CS must be taken high after the final clock in order to latch the data.

In Sleep mode (SLEEP bit = '1'), the data clocked into SDI are routed to the SDO pin directly; the Shift Register is bypassed. The first falling edge of CS starts the operating cycle. When SCLK is continuously applied with CS low, the data clocked into the SDI pin appear on the SDO pin almost immediately (with approximately a 5 ns delay; see the Timing Diagrams section); there is no 24 clock delay, as there is in normal operting mode. While in Sleep mode, no data bits are clocked into the Shift Register, and the device does not receive any new data or commands. Putting the device into Sleep mode eliminates the 24 clock delay from SDI to SDO caused by the

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DB23 DB0

=Don’tCare

Bit23=MSB Bit0=LSB

MultipleReadings

SCLK

SDI

CommandtoRead

DB23 DB0 DB23 DB0 DB23 DB0

CommandtoRead

NOPCommand

(write ‘1’ toNOPbit)

DB23 DB0

SDO

Undefined Datafrom

DB23 DB0 DB23 DB0 DB23 DB0

Datafrom

DB23DB0

SingleReading

SCLK

SDI

READCommandSpecifies

NOPCommand

(write ‘1’ toNOPbit)

DB23

DB23DB0

SDO

Undefined Datafrom

SelectedRegister

DB23

R/W= ‘1’ R/W= ‘0’

R/W= ‘1’ R/W= ‘1’ R/W= ‘1’ R/W= ‘0’

DB23

Command

DB23

Undefined

DB0

DAC8718

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Shift Register, thus greatly speeding up the data transfer. For example, consider three DAC8718s (A, B, and C) in a daisy-chain configuration. The data from the SPI controller are transferred first to A, then to B, and finally to C. In normal daisy-chain operation, a total of 72 clocks are needed to transfer one word to C. However, if A and B are placed into Sleep mode, the first 24 data bits are directly transferred to C (through A and B); therefore, only 24 clocks are needed.

To wake the device up from sleep mode and return to normal operation, either one of following methods can be used:

1. Pull the WAKEUP pin low, which forces the SLEEP bit to '0' and returns the device to normal operating mode.

2. Use the W2 bit and the CS pin.

When the W2 bit = '1', if CS is applied with no more than one falling edge of SCLK, then the rising edge of CS wakes the device from sleep mode back to normal operation. However, the device will not wake-up if more than one falling edge of SCLK exists while CS is low.

Read-Back Operation

The READ command is used to start read-back operation. However, before read-back operation can be initiated, the SDO pin must be enabled by setting the DSDO bit in the Configuration Register to '0'; this bit is cleared by default. Read-back operation is then started by executing a READ command (R/W bit = '1', see Table 9). Bits A4 to A0 in the READ command select the register to be read. The remaining data in the command are don’t care bits. During the next SPI operation, the data appearing on the SDO output are from the previously addressed register. For a read of a single register, a NOP command can be used to clock out the data from the selected register on SDO. Multiple registers can be read if multiple READ commands are issued. The readback diagram in Figure 100 shows the read-back sequence.

Figure 100. Read-Back Operation

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SPI SHIFT REGISTER

The SPI Shift Register is 24 bits wide, as shown in Table 9. The register mapping is shown in Table 10; X = don't care—writing to it has no effect, reading it returns '0'.

Table 9. Shift Register Format

MSB

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15:DB0

R/W X X A4 A3 A2 A1 A0 DATA

R/W Indicates a read from or a write to the addressed register.

R/W = '0' sets a write operation and the data are written to the specified register. R/W = '1' sets a read-back operation. Bits A4 to A0 select the register to be read. The remaining bits

are don’t care bits. During the next SPI operation, the data appearing on SDO pin are from the previously addressed register.

A4:A0 Address bits that specify which register is accessed. DATA 16 data bits

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Table 10. Register Map

ADDRESS BITS DATA BITS

A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3:D0 REGISTER

Configuration

0 0 0 0 0 A/B LD RST PD-A PD-B SCE X GAIN-A GAIN-B DSDO NOP W2 X 0 0 0 0 1 Analog Monitor Select X

0 0 0 1 0 GPIO-2 GPIO-1 GPIO-0 X 0 0 0 1 1 OS15:OS0

0 0 1 0 0 OS15:OS0 0 0 1 0 1 Reserved

0 0 1 1 0 SLEEP Reserved 0 0 1 1 1 DB15:DB0 Broadcast 0 1 0 0 0 DB15:DB0 DAC-0 0 1 0 0 1 DB15:DB0 DAC-1 0 1 0 1 0 DB15:DB0 DAC-2 0 1 0 1 1 DB15:DB0 DAC-3 0 1 1 0 0 DB15:DB0 DAC-4 0 1 1 0 1 DB15:DB0 DAC-5 0 1 1 1 0 DB15:DB0 DAC-6 0 1 1 1 1 DB15:DB0 DAC-7 1 0 0 0 0 Z15:Z0, default = 0 (0000h), twos complement Zero Register-0 1 1 0 0 0 G15:G0, default = 32768 (8000h), straight binary Gain Register-0 1 0 0 0 1 Z15:Z0, default = 0 (0000h), twos complement Zero Register-1 1 1 0 0 1 G15:G0, default = 32768 (8000h), straight binary Gain Register-1 1 0 0 1 0 Z15:Z0, default = 0 (0000h), twos complement Zero Register-2 1 1 0 1 0 G15:G0, default = 32768 (8000h), straight binary Gain Register-2 1 0 0 1 1 Z15:Z0, default = 0 (0000h), twos complement Zero Register-3 1 1 0 1 1 G15:G0, default = 32768 (8000h), straight binary Gain Register-3 1 0 1 0 0 Z15:Z0, default = 0 (0000h), twos complement Zero Register-4 1 1 1 0 0 G15:G0, default = 32768 (8000h), straight binary Gain Register-4 1 0 1 0 1 Z15:Z0, default = 0 (0000h), twos complement Zero Register-5 1 1 1 0 1 G15:G0, default = 32768 (8000h), straight binary Gain Register-5 1 0 1 1 0 Z15:Z0, default = 0 (0000h), twos complement Zero Register-6 1 1 1 1 0 G15:G0, default = 32768 (8000h), straight binary Gain Register-6 1 0 1 1 1 Z15:Z0, default = 0 (0000h), twos complement Zero Register-7 1 1 1 1 1 G15:G0, default = 32768 (8000h), straight binary Gain Register-7

(2)

(3)

(1)

(3)

(1) X = don't care—writing to this bit has no effect; reading the bit returns '0'. (2) Table 7 lists the default values for a dual power supply. Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the

error for symmetrical output. The default value may vary no more than ±10 LSB from the nominal number listed in Table 7. For a single power supply, the Offset DACs are turned off.

(3) Writing to a reserved bit has no effect; reading the bit returns '0'.

(1)

Monitor Register

GPIO Register

Offset DAC-A

Data

Offset DAC-B

Data

Reserved

SPI MODE

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INTERNAL REGISTERS

The DAC8718 internal registers consist of the Configuration Register, the Monitor Register, the DAC Input Data Registers, the Zero Registers, the DAC Data Registers, and the Gain Registers, and are described in the following section.

The Configuration Register specifies which actions are performed by the device. Table 11 shows the details.

Table 11. Configuration Register (Default = 8000h)

BIT NAME VALUE DESCRIPTION

D15 A/B 1 When A/B = '1', reading DAC-x returns the value in the DAC Data Register.

D14 LD 0

D13 RST 0 Set the RST bit to '1' to reset the device; functions the same as a hardware reset. After reset completes, the RST bit

D12 PD-A 0 buffers are in Hi-Z and all analog outputs (V

D11 PD-B 0 buffers are in Hi-Z and all analog outputs (V

D10 SCE 0

D9 — 0 Reserved. Writing to this bit has no effect; reading this bit returns '0'.

D8 GAIN-A 0

D7 GAIN-B 0

D6 DSDO 0

D5 NOP 0

D4 W2 0

D3:D0 — 0 Reserved. Writing to these bits has no effect; reading these bits returns '0'.

DEFAULT

A/B bit. When A/B = '0', reading DAC-x returns the value in the Input Data Register.

When the correction engine is enabled, the data returned from the Input Data Register is the original data written to the bus, and the value in the DAC Data Register is the corrected data.

Synchronously update DACs bit. When LDAC is tied high, setting LD = '1' at any time after the write operation and the correction process complete synchronously updates all DAC latches with the content of the corresponding DAC Data Register, and sets V level. The DAC8718 updates the DAC latch only if it has been accessed since the last time LDAC was brought low or the LD bit was set to '1', thereby eliminating unnecessary glitch. Any DACs that were not accessed are not reloaded. After updating, the bit returns to '0'. When the correction engine is turned off, bit LD can be set to '1' any time after the writing operation is complete; the DAC latch is immediately updated when bit LD is set. When the LDAC pin is tied low, this bit is ignored.

Software reset bit. returns to '0'.

Power-down bit for Group A (DAC-0, DAC-1, DAC-2, and DAC-3). Setting the PD-A bit to '1' places Group A (DAC-0, DAC-1, DAC-2, and DAC-3) into power-down operation. All output

still active. Setting the PD-A bit to '0' returns group A to normal operation.

Power-down bit for Group B (DAC-4, DAC-5, DAC-6, and DAC-7). Setting the PD-B bit to '1' places Group B (DAC-4, DAC-5, DAC-6, and DAC-7) into power-down operation. All output

still active. Setting the PD-B bit to '0' returns group B to normal operation.

System-calibration enable bit. Set the SCE bit to '1' to enable the correction engine. When the engine is enabled, the input data are adjusted by the correction engine according to the contents of the corresponding Gain Register and Zero Register. The results are transferred to the corresponding DAC Data Register, and finally loaded into the DAC latch, which sets the V output level. Set the SCE bit to '0' to turn off the correction engine. When the engine is turned off, the input data are transferred to the corresponding DAC Data Register immediately, and then loaded into the DAC latch, which sets the output voltage. Refer to the User Calibration for Zero-Code Error and Gain Error section for details.

Gain bit for Group A (DAC-0, DAC-1, DAC-2, and DAC-3). Updating this bit to a new value automatically resets the Offset DAC-A Register to the factory-trimmed value for the new gain setting. Set the GAIN-A bit to '0' for an output span = 6 × REF-A. Set the GAIN-A bit to '1' for an output span = 4 × REF-A.

Gain bit for Group B (DAC-4, DAC-5, DAC-6, and DAC-7). Updating this bit to a new value automatically resets the Offset DAC-B Register to the factory-trimmed value for the new gain setting. Set the GAIN-B bit to '0' for an output span = 6 × REF-B. Set the GAIN-B bit to '1' for an output span = 4 × REF-B.

Disable SDO bit. Set the DSDO bit to '0' to enable the SDO pin (default). The SDO pin works as a normal SPI output. Set the DSDO bit to '1' to disable the SDO pin. The SDO pin is always in a Hi-Z state no matter what the status of the CS pin is.

No operation bit. During a write operation, setting the NOP bit to '1' has no effect (the bit returns to '0' when the write operation completes). Setting the NOP bit to '0', returns the device to normal operation. During a read operation, the bit always returns “0”

Second wake-up operation bit. If the WAKEUP pin is high, an alternative method to wake-up the device from sleep in SPI is by using the CS pin. When W2 = '1', the rising edge of CS restores the device from sleep mode to normal operation, if no more than one falling edge of SCLK exists while CS is low. However, the device will not wake up if more than one falling edge of SCLK exists. Setting the W2 bit to '0' disables this function, and the rising edge of CS does not wake up the device. If the WAKEUP is low, this bit is ignored and the device is always in normal mode.

-X) connect to AGND-A through an internal 15-kΩ resistor. The interface is

OUT

-X) connect to AGND-B through an internal 15-kΩ resistor. The interface is

OUT

to a new

-x pin

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Monitor Register (default = 0000h).

The Monitor Register selects one of the DAC outputs, auxiliary analog inputs, reference buffer outputs, or offset DAC outputs to be monitored through the V

pin. When bits [D15:D4] = '0', the monitor is disabled and V

MON

in a Hi-Z state. Note that if any value is written other than those specified in Table 12, the Monitor Register stores the invalid

value; however, the V

pin is forced into a Hi-Z state.

MON

Table 12. Monitor Register (Default = 0000h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3:D0 V

0 0 0 0 0 0 0 0 0 0 0 1 X 0 0 0 0 0 0 0 0 0 0 1 0 X Reference buffer A output 0 0 0 0 0 0 0 0 0 1 0 1 X Offset DAC B output 0 0 0 0 0 0 0 0 0 1 1 0 X Offset DAC A output 0 0 0 0 0 0 0 0 0 1 0 0 X AIN-0 0 0 0 0 0 0 0 0 1 0 0 0 X AIN-1 0 0 0 0 0 0 0 1 0 0 0 0 X DAC-0 0 0 0 0 0 0 1 0 0 0 0 0 X DAC-1 0 0 0 0 0 1 0 0 0 0 0 0 X DAC-2 0 0 0 0 1 0 0 0 0 0 0 0 X DAC-4 0 0 0 1 0 0 0 0 0 0 0 0 X DAC-4 0 0 1 0 0 0 0 0 0 0 0 0 X DAC-5 0 1 0 0 0 0 0 0 0 0 0 0 X DAC-6 1 0 0 0 0 0 0 0 0 0 0 0 X DAC-7 0 0 0 0 0 0 0 0 0 0 0 0 X Monitor function disabled, Hi-Z (default)

(1) X = don't care.

(1)

CONNECTS TO

MON

Reference buffer B output

BLANKSPACE

GPIO Register (default = E000h). The GPIO Register determines the status of each GPIO pin.

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

GPIO-2 GPIO-1 GPIO-0 X X X X X X X X X X X X X

GPIO-2:0 For write operations, the GPIO-n pin operates as an output. Writing a '1' to the GPIO-n bit sets the

GPIO-n pin to high impedance, and writing a '0' sets the GPIO-n pin to logic low. An external pull-up resistor is required when using the GPIO-n pin as an output.

For read operations, the GPIO-n pin operates as an input. Read the GPIO-n bit to receive the status of the corresponding GPIO-n pin. Reading a '0' indicates that the GPIO-n pin is low, and reading a '1' indicates that the GPIO-n pin is high.

After power-on reset, or any forced hardware or software reset, all GPIO-n bits are set to '1', and the GPIO pins are in a high impedance state.

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Offset DAC-A/B Registers (default = 999Ah for dual supplies or 0000h for single supplies). The Offset DAC-A and Offset DAC-B registers contain, by default, the factory-trimmed Offset DAC code

providing optimal offset and span for symmetric bipolar operation when dual supplies are detected, and contain code 0000h when a single supply is detected.

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

OS15 OS14 OS13 OS12 OS11 OS10 OS9 OS8 OS7 OS6 OS5 OS4 OS3 OS2 OS1 OS0

OS15:0 For dual-supply operation, the default code for a gain of 6 is 999Ah with a ±10 LSB variation,

depending on the linearity of each Offset DAC. The default code for a gain of 4 is AAABh with a ±10 LSB variation. The default codes of Offset DAC-A and Offset DAC-B registers are independently factory trimmed for both gains of 6 and 4.

When single-supply operation is present, writing to these registers is ignored and reading returns 0000h. When dual-supply operation is present, updating the GAIN-A (GAIN-B) bit on the configuration register automatically reloads the factory-trimmed code into the Offset DAC-A (Offset DAC-B) register for the new GAIN-A (GAIN-B) setting. See the Offset DACs for further details.

BLANKSPACE

SPI MODE Register (default = 0000h). The SPI Mode Register is used to put the device into SPI sleep mode.

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

SLEEP X X X X X X X X X X X X X X X

SLEEP Set the SLEEP bit to '1' to put the device into SPI sleep mode.

When the SLEEP bit = '0', the SPI is in normal mode. The bit is cleared ('0') after a hardware reset (through the RST pin) or if the WAKEUP pin is low.

For normal SPI operation, the data entering the SDI pin is transferred into the Shift Register. However, for SPI sleep mode, the Shift Register is bypassed. The data entering into the SDI pin are directly transferred to the SDO pin instead of the Shift Register.

BLANKSPACE

Broadcast Register.

The DAC8718 broadcast register can be used to update all eight DAC register channels simultaneously using data bits D15:D0. This write-only register uses address A4:A0 = 07h, and is only available when the SCE bit = '0' (default). If the SCE bit = '1', this register is ignored. Reading this register always returns 0000h.

BLANKSPACE

Input Data Register for DAC-n, where n = 0 to 7 (default = 0000h). This register stores the DAC data written to the device when the SCE bit = '1' and is controlled by the correction

engine. When the SCE bit = '0' (default), the DAC Data Register stores the DAC data written to the device. When the data are loaded into the corresponding DAC latch, the DAC output changes to the new level defined by the DAC latch. The default value after power-on or reset is 0000h.

Table 13. DAC-n

MSB LSB

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

(2)

DB15

(1) n = 0, 1, 2, 3, 4, 5, 6, or 7. (2) DB15:DB0 are the DAC data bits.

DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

(1)

Input Data Register

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Zero Register n, where n = 0 to 7 (default = 0000h).

The Zero Register stores the user-calibration data that are used to eliminate the offset error. The data are 16 bits wide, 1 LSB/step, and the total adjustment is –32768 LSB to +32767 LSB, or ±50% of full-scale range. The Zero Register uses a twos complement data format.

Table 14. Zero Register

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Z15 Z14 Z13 Z12 Z11 Z10 Z9 Z8 Z7 Z6 Z5 Z4 Z3 Z2 Z1 Z0

Z15:Z0—OFFSET BITS ZERO ADJUSTMENT

7FFFh +32767 LSB 7FFEh +32766 LSB

••• ••• ••• ••• ••• ••• 0001h +1 LSB 0000h 0 LSB (default) FFFFh –1 LSB

••• ••• ••• ••• ••• ••• 8001h –32767 LSB 8000h –32768 LSB

BLANKSPACE

Gain Register n, where n = 0 to 7 (default = 8000h). The Gain Register stores the user-calibration data that are used to eliminate the gain error. The data are 16 bits

wide, 0.0015% FSR/step, and the total adjustment range 0.5 to 1.5. The Gain Register uses a straight binary data format.

Table 15. Gain Register

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

G15 G14 G13 G12 G11 G10 G9 G8 G7 G6 G5 G4 G3 G2 G1 G0

G15:G0—GAIN-CODE BITS GAIN ADJUSTMENT COEFFICIENT

FFFFh 1.499985

FFFEh 1.499969

••• ••• ••• ••• ••• ••• 8001h 1.000015 8000h 1 (default)

7FFFh 0.999985

••• ••• ••• ••• ••• ••• 0001h 0.500015 0000h 0.5

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AIN-1

V -4

OUT

REF-B

V -5

OUT

V -6

OUT

AGND-B

OFFSET-B

V -7

OUT

AIN-0

V -3

OUT

REF-A

V -2

OUT

V -1

OUT

AGND-A

OFFSET-A

V -0

OUT

MON

WAKEUP

LDAC

SDO

SDI

SCLK

IOV

DGND

RSTSEL

USB/BTC

64 63 62 61 60 59 58 57 56 55 54

18 19 20

21 22

25 26

53 52 51 50 49

28 29 30 31 32

DAC8718

GPIO-2

CLR

RST

DGNDNCNC

DGND

GPIO-1

GPIO-0

10 Fm

V -3

OUT

AIN-0

REF-A

V -2

OUT

V -1

OUT

OFFSET-A

V -0

OUT

10 Fm

MON

RST

CLR

10kW 10kW 10kW

1 Fm

V -7

OUT

OFFSET-B

10 Fm

V -4

OUT

AIN-1

REF-B

V -5

OUT

V -6

OUT

10 Fm

WAKEUP

LDAC

SDO

SDICSSCLK

1 Fm

IOV

RSTSEL

10kW

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APPLICATION INFORMATION

BASIC OPERATION

The DAC8718 is a highly-integrated device with high-performance reference buffers and output buffers, greatly reducing the printed circuit board (PCB) area and production cost. On-chip reference buffers eliminate the need for a negative external reference. Figure 101 shows a basic application for the DAC8718.

NOTES: AVDD = +15V, AVSS = -15V, DVDD = +5V, IOVDD = +1.8V to +5V, REF-A = +5V, and REF-B = +2.5V.

NOTES: The OFFSET-A and OFFSET-B pins must be connected to the AGND pin when used in unipolar operation.

Figure 101. Basic Application Example

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PRECISION VOLTAGE REFERENCE SELECTION

To achieve the optimum performance from the DAC8718 over the full operating temperature range, a precision voltage reference must be used. Careful consideration should be given to the selection of a precision voltage reference. The DAC8718 has two reference inputs, REF-A and REF-B. The voltages applied to the reference inputs are used to provide a buffered positive reference for the DAC cores. Therefore, any error in the voltage reference is reflected in the outputs of the device. There are four possible sources of error to consider when choosing a voltage reference for high-accuracy applications: initial accuracy, temperature coefficient of the output voltage, long-term drift, and output voltage noise. Initial accuracy error on the output voltage of an external reference can lead to a full-scale error in the DAC. Therefore, to minimize these errors, a reference with low initial accuracy error specification is preferred. Long-term drift is a measure of how much the reference output voltage drifts over time. A reference with a tight, long-term drift specification ensures that the overall solution remains relatively stable over its entire lifetime. The temperature coefficient of a reference output voltage affects the output drift when the temperature changes. Choose a reference with a tight temperature coefficient specification to reduce the dependence of the DAC output voltage on ambient conditions. In high-accuracy applications, which have a relatively low noise budget, the reference output voltage noise also must be considered. Choosing a reference with as low an output noise voltage as practical for the required system resolution is important. Precision voltage references such as TI's REF50xx (2V to 5V) and REF32xx (1.25V to 4V) provide a low-drift, high-accuracy reference voltage.

POWER-SUPPLY NOISE

The DAC8718 must have ample supply bypassing of 1μF to 10μF in parallel with 0.1μF on each supply, located as close to the package as possible; ideally, immediately next to the device. The 1μF to 10μF capacitors must be the tantalum-bead type. The 0.1μF capacitor must have low effective series resistance (ESR) and low effective series inductance (ESI), such as common ceramic types, which provide a low-impedance path to ground at high frequencies to handle transient currents because of internal logic switching. The power-supply lines must be as large a trace as possible to provide low-impedance paths and reduce the effects of glitches on the power-supply line. Apart from these considerations, the wideband noise on the AVDD, AVSS, DVDDand IOVDDsupplies should be filtered before feeding to the DAC to obtain the best possible noise performance.

LAYOUT

Precision analog circuits require careful layout, adequate bypassing, and a clean, well-regulated power supply to obtain the best possible dc and ac performance. Careful consideration of the power-supply and ground-return layout helps to meet the rated performance. DGND is the return path for digital currents and AGND is the power ground for the DAC. For the best ac performance, care should be taken to connect DGND and AGND with very low resistance back to the supply ground. The PCB must be designed so that the analog and digital sections are separated and confined to certain areas of the board. If multiple devices require an AGND-to-DGND connection, the connection is to be made at one point only. The star ground point is established as close as possible to the device.

The power-supply traces must be as large as possible to provide low impedance paths and reduce the effects of glitches on the power-supply line. Fast switching signals must never be run near the reference inputs. It is essential to minimize noise on the reference inputs because it couples through to the DAC output. Avoid crossover of digital and analog signals. Traces on opposite sides of the board must run at right angles to each other. This configuration reduces the effects of feedthrough on the board. A microstrip technique may be considered, but is not always possible with a double-sided board. In this technique, the component side of the board is dedicated to the ground plane, and signal traces are placed on the solder-side.

Each DAC group has a ground pin, AGND-x, which is the ground of the output from the DACs in the group. It must be connected directly to the corresponding reference ground in low-impedance paths to get the best performance. AGND-A must be connected with REFGND-A and AGND-B must be connected with REFGND-B. AGND-A and AGND-B must be tied together and connected to the analog power ground and DGND.

During single-supply operation, the OFFSET-x pins must be connected to AGND-x with a low-impedance path because these pins carry DAC-code-dependent current. Any resistance from OFFSET-x to AGND-x causes a voltage drop by this code-dependent current. Therefore, it is very important to minimize routing resistance to AGND-x or to any ground plane that AGND-x is connected to.

Product Folder Link(s): DAC8718

PACKAGE OPTION ADDENDUM

www.ti.com 5-May-2010

PACKAGING INFORMATION

Orderable Device Status

(1)

Package

Type

Package

Drawing

Pins Package

Qty

Eco Plan

DAC8718SPAG ACTIVE TQFP PAG 64 160 Green (RoHS &

(2)

Lead/Ball Finish MSL Peak Temp

CU NIPDAU Level-4-260C-72 HR

(3)

no Sb/Br)

DAC8718SPAGR ACTIVE TQFP PAG 64 1500 Green (RoHS &

CU NIPDAU Level-4-260C-72 HR

no Sb/Br)

DAC8718SRGZR ACTIVE VQFN RGZ 48 2500 Green (RoHS &

CU NIPDAU Level-3-260C-168 HR

no Sb/Br)

DAC8718SRGZT ACTIVE VQFN RGZ 48 250 Green (RoHS &

CU NIPDAU Level-3-260C-168 HR

no Sb/Br)

(1)

The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in

a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.

(2)

Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check

http://www.ti.com/productcontent for the latest availability information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements

for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(3)

MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder

temperature.

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In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com 20-Jul-2010

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type

DAC8718SPAGR TQFP PAG 64 1500 330.0 24.4 13.0 13.0 1.5 16.0 24.0 Q2 DAC8718SRGZR VQFN RGZ 48 2500 330.0 16.4 7.3 7.3 1.5 12.0 16.0 Q2 DAC8718SRGZT VQFN RGZ 48 250 330.0 16.4 7.3 7.3 1.5 12.0 16.0 Q2

Package

Drawing

Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm)B0(mm)K0(mm)P1(mm)W(mm)

Pin1

Quadrant

Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com 20-Jul-2010

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

DAC8718SPAGR TQFP PAG 64 1500 346.0 346.0 41.0 DAC8718SRGZR VQFN RGZ 48 2500 333.2 345.9 28.6 DAC8718SRGZT VQFN RGZ 48 250 333.2 345.9 28.6

Pack Materials-Page 2

MECHANICAL DATA

MTQF006A – JANUARY 1995 – REVISED DECEMBER 1996

PAG (S-PQFP-G64) PLASTIC QUAD FLATPACK

0,50

1,05

0,95

0,27 0,17

7,50 TYP

10,20

9,80

12,20

11,80

0,08

0,05 MIN

Seating Plane

0,13 NOM

Gage Plane

0,25

0°–7°

0,75 0,45

1,20 MAX

NOTES: A. All linear dimensions are in millimeters.

B. This drawing is subject to change without notice.

C. Falls within JEDEC MS-026

0,08

4040282/C 11/96

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TEXAS INSTRUMENTS DAC8718 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

DESCRIPTION

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS: Dual-Supply

ELECTRICAL CHARACTERISTICS: Single-Supply

FUNCTIONAL BLOCK DIAGRAM

PIN CONFIGURATIONS

TIMING DIAGRAMS

TIMING CHARACTERISTICS: IOVDD= +5V

TIMING CHARACTERISTICS: IOVDD= +3V

TIMING CHARACTERISTICS: IOVDD= +1.8V

TYPICAL CHARACTERISTICS: Bipolar

TYPICAL CHARACTERISTICS: Unipolar

THEORY OF OPERATION

GENERAL DESCRIPTION

CHANNEL GROUPS

USER-CALIBRATION FOR ZERO-CODE ERROR AND GAIN ERROR

INPUT DATA FORMAT

OFFSET DACS

OUTPUT AMPLIFIERS

GENERAL-PURPOSE INPUT/OUTPUT PINS (GPIO-0 to GPIO-2)

ANALOG OUTPUT PIN (CLR)

POWER-ON RESET

HARDWARE RESET

UPDATING THE DAC OUTPUTS

Asynchronous Mode

Synchronous Mode

ANALOG INPUT PINS (AIN-0 and AIN-1)

POWER-DOWN MODE

POWER-ON RESET SEQUENCING

SERIAL INTERFACE

SPI Shift Register

Stand-Alone Operation

Daisy-Chain Operation

Read-Back Operation

SPI SHIFT REGISTER

INTERNAL REGISTERS

APPLICATION INFORMATION

BASIC OPERATION

PRECISION VOLTAGE REFERENCE SELECTION

POWER-SUPPLY NOISE

LAYOUT