Analog AD5724, AD5734, AD5754 Data Sheet

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Page 1

Complete, Quad, 12-/14-/16-Bit, Serial Input,

Unipolar/Bipolar Voltage Output DACs

AD5724/AD5734/AD5754

Rev. F Document Feedback

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

Trademarks and registered trademarks are the property of their respective owners.

Technical Support www.analog.com

06468-001

C C

DAC

ACB

INP

PUT

INP

DAC

LDA

REF

OUT

REFERENCE BUFFERS

SDI

CLK

SYN

GND

N/2sCO

DAC_

GND (2) SIG_G

ND (2)

AD5724/AD5734/AD5754

NPU

T SH

IFT

EGI

STE

AND

ONTROL

LOG

INP

DAC

AD5724: n = 12-BIT AD5734: n = 14-BIT AD5754: n = 16-BIT

Data Sheet

FEATURES

Complete, quad, 12-/14-/16-bit digital-to-analog

converter (DAC) Operates from single/dual supplies Software programmable output range

+5 V, +10 V, +10.8 V, ±5 V, ±10 V, ±10.8 V INL error: ±16 LSB maximum, DNL error: ±1 LSB maximum Total unadjusted error (TUE): 0.1% FSR maximum Settling time: 10 µs typical Integrated reference buffers Output control during power-up/brownout Simultaneous updating via Asynchronous

to zero scale or midscale

CLR DSP-/microcontroller-compatible serial interface 24-lead TSSOP Operating temperature range: −40°C to +85°C iCMOS process technology

APPLICATIONS

Industrial automation Closed-loop servo control, process control Automotive test and measurement Programmable logic controllers

LDAC

GENERAL DESCRIPTION

The AD5724/AD5734/AD5754 are quad, 12-/14-/16-bit, serial input, voltage output DACs. The devices operate from singlesupply voltages from +4.5 V up to +16.5 V or dual-supply voltages from ±4.5 V up to ±16.5 V. Nominal full-scale output range is software-selectable from +5 V, +10 V, +10.8 V, ± 5 V, ±10 V, or ±10.8 V. Integrated output amplifiers, reference buffers, and proprietary power-up/power-down control circuitry are also provided.

The devices offer guaranteed monotonicity, integral nonlinearity (INL) of ±16 LSB maximum, low noise, and 10 µs maximum settling time.

The AD5724/AD5734/AD5754 use a serial interface that operates at clock rates up to 30 MHz and are compatible with DSP and microcontroller interface standards. Double buffering allows the simultaneous updating of all DACs. The input coding is user-selectable twos complement or offset binary for a bipolar output (depending on the state of Pin BIN/ binary for a unipolar output. The asynchronous clear function clears all DAC registers to a user-selectable zero-scale or midscale output. The devices are available in a 24-lead TSSOP and offer guaranteed specifications over the −40°C to +85°C industrial temperature range.

2sComp

), and straight

For analog systems designers within industrial/instrumentation equipment OEMs that need high performance ICs at higher-voltage levels, iCMOS® is a technology

platform that enables the development of analog ICs capable of 30 V and operating at ±15 V supplies while allowing dramatic reductions in power consumption and package size, as well as increased ac and dc performance.

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

Page 2

AD5724/AD5734/AD5754 Data Sheet

Features .............................................................................................. 1

Applications ....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

AC Performance Characteristics ................................................ 5

Timing Characteristics ................................................................ 5

Timing Diagrams .......................................................................... 6

Absolute Maximum Ratings ............................................................ 8

ESD Caution .................................................................................. 8

Pin Configuration and Function Descriptions ............................. 9

Typical Performance Characteristics ........................................... 10

Terminology .................................................................................... 16

Theory of Operation ...................................................................... 18

Architecture ................................................................................. 18

Power-Up Sequence ................................................................... 18

Serial Interface ............................................................................ 18

Load DAC (

Asynchronous Clear (

Configuring the AD5724/AD5734/AD5754 .......................... 20

LDAC

)..................................................................... 20

CLR

) ....................................................... 20

Transfer Function ....................................................................... 20

Input Shift Register .................................................................... 24

DAC Register .............................................................................. 24

Output Range Select Register ................................................... 25

Control Register ......................................................................... 25

Power Control Register.............................................................. 26

Features ............................................................................................ 27

Analog Output Control ............................................................. 27

Power-Down Mode .................................................................... 27

Overcurrent Protection ............................................................. 27

Thermal Shutdown .................................................................... 27

Applications Information .............................................................. 28

+5 V/±5 V Operation ................................................................ 28

Alternative Power-Up Sequence Support ............................... 28

Layout Guidelines....................................................................... 28

Galvanically Isolated Interface ................................................. 29

Voltage Reference Selection ...................................................... 29

Microprocessor Interfacing ....................................................... 29

Outline Dimensions ....................................................................... 31

Ordering Guide .......................................................................... 31

REVISION HISTORY

2/2017—Rev. E to Rev. F

Added Power-Up Sequence Section ............................................. 18

Changes to Table 7 and Table 8 ..................................................... 21

Changes to Table 10 and Table 11 ................................................ 22

Changes to Table 13 and Table 14 ................................................ 23

Changes to Analog Output Control Section ............................... 27

Added Alternative Power-Up Sequence Support Section,

Figure 43, and Figure 44; Renumbered Sequentially ................. 28

2/2016—Rev. D to Rev. E

Changes to Table 1...................................................................................... 3

Change to Table 5 ......................................................................................... 9

7/2011—Rev. C to Rev. D

Changes to Table 3: t7, t8, t10 Limits ....................................................... 5

Rev. F | Page 2 of 31

3/2011—Rev. B to Rev. C

Changes to Configuring the AD5724/

Section .............................................................................................. 20

8/2010—Rev. A to Rev. B

Changes to Table 27 ....................................................................... 26

4/2010—Rev. 0 to Rev. A

Changes to Junction Temperature, T

Changes to Exposed Pad Description, Table 5 .............................. 9

Added Exposed Paddle Notation to Outline Dimensions ........ 30

8/2008—Revision 0: Initial Version

AD5734/AD5754

max Parameter, Table 4 ... 8

Page 3

Data Sheet AD5724/AD5734/AD5754

ACCURACY

Outputs unloaded

Total Unadjusted Error (TUE)

Offset Error TC3

±4 ppm FSR/°C

Gain Error

−0.025

+0.025

% FSR

±10 V range, TA = 25°C, error at other

SPECIFICATIONS

AVDD = 4.5 V1 to 16.5 V; AVSS = −4.5 V1 to −16.5 V, or 0 V; GND = 0 V; REFIN= 2.5 V; DVCC = 2.7 V to 5.5 V; R C

= 200 pF; all specifications T

LOAD

MIN

to T

MAX

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

Resolution

AD5754 16 Bits AD5734 14 Bits AD5724 12 Bits

LOAD

= 2 kΩ;

A Version −0.3 +0.3 % FSR B Version −0.1 +0.1 % FSR

Relative Accuracy (INL)2

AD5754 −16 +16 LSB AD5734 −4 +4 LSB

AD5724 −1 +1 LSB

Differential Nonlinearity (DNL) −1 +1 LSB All models, all versions, guaranteed monotonic Bipolar Zero Error −6 +6 mV ±10 V range, TA = 25°C, error at other temp-

Bipolar Zero Error TC3 ±4 ppm FSR/°C Zero-Scale Error −6 +6 mV ±10 V range, TA = 25°C, error at other temp-

Zero-Scale Error TC3 ±4 ppm FSR/°C Offset Error −6 +6 mV +10 V range, TA = 25°C, error at other

Gain Error3 −0.065 0 % FSR +10 V and +5 V ranges, TA = 25°C, error at other

Gain Error3 0 +0.08 % FSR ±5 V range, TA = 25°C, error at other

Gain Error TC3 ±8 ppm FSR/°C DC Crosstalk3 120 µV

REFERENCE INPUT3

Reference Input Voltage 2.5 V ±1% for specified performance DC Input Impedance 1 5 MΩ Input Current −2 ±0.5 +2 µA Reference Range 2 3 V

OUTPUT CHARACTERISTICS3

Output Voltage Range −10.8 +10.8 V AVDD/AVSS = ±11.7 V min, REFIN = +2.5 V

−12 +12 V AVDD/AVSS = ±12.9 V min, REFIN = +3 V Headroom Required 0.5 0.9 V Output Voltage TC ±4 ppm FSR/°C Short-Circuit Current 20 mA Load 2 kΩ For specified performance Capacitive Load Stability 4000 pF DC Output Impedance 0.5 Ω

±10 V range ±10 V range

eratures obtained using bipolar zero error TC

eratures obtained using zero-scale error TC

temperatures obtained using offset error TC

temperatures obtained using gain error TC

Rev. F | Page 3 of 31

Page 4

AD5724/AD5734/AD5754 Data Sheet

Pin Capacitance

Per pin

DVCC

2.7 5.5

Parameter Min Typ Max Unit Test Conditions/Comments

DIGITAL INPUTS3 DVCC = 2.7 V to 5.5 V, JEDEC compliant

Input High Voltage, VIH 2 V Input Low Voltage, VIL 0.8 V Input Current ±1 µA Per pin

DIGITAL OUTPUTS (SDO)3

Output Low Voltage, VOL 0.4 V DVCC = 5 V ± 10%, sinking 200 µA Output High Voltage, VOH DVCC − 1 V DV Output Low Voltage, VOL 0.4 V DVCC = 2.7 V to 3.6 V, sinking 200 µA Output High Voltage, VOH DVCC − 0.5 V DVCC = 2.7 V to 3.6 V, sourcing 200 µA High Impedance Leakage Current −1 +1 µA High Impedance Output Capacitance 5 pF

POWER REQUIREMENTS

AVDD 4.5 16.5 V AVSS −4.5 −16.5 V

= 5 V ± 10%, sourcing 200 µA

Power Supply Sensitivity

∆V

/∆ΑVDD −65 dB

OUT

AIDD 2.5 mA/channel Outputs unloaded

1.75 mA/channel AVSS = 0 V, outputs unloaded AISS 2.2 mA/channel Outputs unloaded DICC 0.5 3 µA VIH = DVCC, VIL = GND Power Dissipation 310 mW ±16.5 V operation, outputs unloaded 115 mW 16.5 V operation, AVSS = 0 V, outputs unloaded Power-Down Currents

AIDD 40 µA AISS 40 µA DICC 300 nA

For specified performance, maximum headroom requirement is 0.9 V.

INL is measured from Code 512, Code 128, and Code 32 for the AD5754, the AD5734, and the AD5724, respectively.

Guaranteed by characterization; not production tested.

Rev. F | Page 4 of 31

Page 5

Data Sheet AD5724/AD5734/AD5754

DAC to DAC Crosstalk

10 nV-sec

Parameter

Limit at t

, t

Unit

Description

t12

µs typ

DAC output settling time

t13

ns min

pulse width low

AC PERFORMANCE CHARACTERISTICS

AVDD = 4.5 V1 to 16.5 V; AVSS = −4.5 V1 to −16.5 V, or 0 V; GND = 0 V; REFIN= 2.5 V; DVCC = 2.7 V to 5.5 V; R C

= 200 pF; all specifications T

LOAD

MIN

to T

MAX

Table 2.

A, B Version Parameter2 Min Typ Max Unit Test Conditions/Comments

DYNAMIC PERFORMANCE

Output Voltage Settling Time 10 12 µs 20 V step to ±0.03% FSR

7.5 8.5 µs 10 V step to ±0.03% FSR 5 µs 512 LSB step settling (16-bit resolution) Slew Rate 3.5 V/µs Digital-to-Analog Glitch Energy 13 nV-sec Glitch Impulse Peak Amplitude 35 mV Digital Crosstalk 10 nV-sec

Digital Feedthrough 0.6 nV-sec Output Noise

0.1 Hz to 10 Hz Bandwidth 15 µV p-p 0x8000 DAC code

100 kHz Bandwidth 80 µV rms Output Noise Spectral Density 320 nV/√Hz Measured at 10 kHz, 0x8000 DAC code

For specified performance, maximum headroom requirement is 0.9 V.

Guaranteed by design and characterization. Not production tested.

TIMING CHARACTERISTICS

AVDD = 4.5 V to 16.5 V; AVSS = −4.5 V to −16.5 V, or 0 V; GND = 0 V; REFIN = 2.5 V; DVCC = 2.7 V to 5.5 V; R all specifications T

MIN

to T

, unless otherwise noted.

MAX

LOAD

= 2 kΩ;

LOAD

= 2 kΩ; C

= 200 pF;

LOAD

Table 3.

1, 2, 3

MIN

MAX

t1 33 ns min SCLK cycle time t2 13 ns min SCLK high time t3 13 ns min SCLK low time t4 13 ns min t5 13 ns min SCLK falling edge to t6 100 ns min Minimum

falling edge to SCLK falling edge setup time

SYNC

high time (write mode)

SYNC t7 7 ns min Data setup time t8 2 ns min Data hold time t9 20 ns min t10 130 ns min t11 20 ns min

falling edge to

LDAC

rising edge to

SYNC

pulse width low

LDAC

SYNC

LDAC

CLR

t14 2.5 µs max

13 ns min

40 ns max SCLK rising edge to SDO valid (C

t17 200 ns min Minimum

Guaranteed by characterization; not production tested.

All input signals are specified with tR = tF = 5 ns (10% to 90% of DVCC) and timed from a voltage level of 1.2 V.

See Figure 2, Figure 3, and Figure 4.

Daisy-chain and readback mode.

= capacitive load on SDO output.

L SDO

pulse activation time

CLR

rising edge to SCLK rising edge

SYNC

high time (readback/daisy-chain mode)

SYNC

rising edge

falling edge

= 15 pF)

L SDO

Rev. F | Page 5 of 31

Page 6

AD5724/AD5734/AD5754 Data Sheet

TIMING DIAGRAMS

SCLK

SYNC

SDIN

LDAC

OUT

CLR

OUT

4221

DB23

DB0

06468-002

Figure 2. Serial Interface Timing Diagram

SCLK

SYNC

SDIN

SDO

LDAC

8442

INPUT WORD FOR DAC N – 1INPUT WORD FOR DAC N

DB23

INPUT WORD FOR DAC NUNDEFINED

D0BD32BD0BD32B

DB0

06468-003

Figure 3. Daisy-Chain Timing Diagram

Rev. F | Page 6 of 31

Page 7

Data Sheet AD5724/AD5734/AD5754

SCLK

SYNC

24 24

SDIN

SDO

DB23 DB0 DB23 DB0

REGIST ER TO BE RE AD

DB23 DB0 DB23 DB0

UNDEFINED

NOP CONDI TIONINPUT WORD SPECIFIES

SELECTED REGISTER DATA

CLOCKED O UT

Figure 4. Readback Timing Diagram

06468-004

Rev. F | Page 7 of 31

Page 8

AD5724/AD5734/AD5754 Data Sheet

(whichever is less)

Digital Outputs to GND

−0.3 V to DVCC + 0.3 V or 7 V Operating Temperature Range, TA

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted. Transient currents of up to 100 mA do not cause SCR latch-up.

Table 4.

Parameter Rating

AVDD to GND −0.3 V to +17 V AVSS to GND +0.3 V to −17 V DVCC to GND −0.3 V to +7 V Digital Inputs to GND −0.3 V to DVCC + 0.3 V or 7 V

(whichever is less) REFIN to GND −0.3 V to +5 V V

A, V

B, V

C, V

OUT

DAC_GND to GND −0.3 V to +0.3 V SIG_GND to GND −0.3 V to +0.3 V

Industrial −40°C to +85°C Storage Temperature Range −65°C to +150°C Junction Temperature, TJ max 150°C 24-Lead TSSOP Package

θJA Thermal Impedance 42°C/W

θJC Thermal Impedance 9°C/W Power Dissipation (TJ max − TA)/ θJA Lead Temperature JEDEC industry standard

Soldering J-STD-020 ESD (Human Body Model) 3.5 kV

D to GND AVSS to AVDD

OUT

Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

ESD CAUTION

Rev. F | Page 8 of 31

Page 9

Data Sheet AD5724/AD5734/AD5754

06468-005

24 23 22 21 20 19 18 17 16 15 14 13

1 2 3 4 5 6 7 8

9 10 11 12

AD5724/ AD5734/

AD5754

CLR

LDAC

OUT

SYNC

BIN/2sCOMP

GND

SDO

REFIN

SIG_GND

SCLK

SDIN

OUT

SIG_GND DAC_GND

DAC_GND

TOP VIEW

(Not to S cale)

NOTES

1. NC = NO CONNE CT.

2. IT IS RECOMMENDED THAT THE EXPOSED PAD BE THERMALL Y CONNECTED TO A COPPER PL ANE FOR ENHANCED THE RM AL PERFORM ANCE .

Load DAC, Logic Input. This is used to update the DAC registers and consequently, the analog outputs. When

held high during the write cycle, the DAC input register is updated, but the output update is held off until the

External Reference Voltage Input. Reference input range is 2 V to 3 V. REFIN = 2.5 V for specified performance.

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 5. Pin Configuration

Table 5. Pin Function Descriptions

Pin No. Mnemonic Description

1 AVSS Negative Analog Supply. Voltage ranges from −4.5 V to −16.5 V. This pin can connect to 0 V if output ranges

are unipolar. 2, 6, 12, 13 NC No connect. Do not connect to these pins. 3 V 4 V 5 BIN/

A Analog Output Voltage of DAC A. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.

OUT

B Analog Output Voltage of DAC B. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.

OUT

2sCOMP

Determines the DAC coding for a bipolar output range. This pin must be hardwired to either DVCC or GND.

When hardwired to DVCC, input coding is offset binary. When hardwired to GND, input coding is twos

complement. (For unipolar output ranges, coding is always straight binary). 7

Active Low Input. This is the frame synchronization signal for the serial interface. While

SYNC

transferred on the falling edge of SCLK. Data is latched on the rising edge of 8 SCLK Serial Clock Input. Data is clocked into the shift register on the falling edge of SCLK. This operates at clock

speeds up to 30 MHz. 9 SDIN Serial Data Input. Data must be valid on the falling edge of SCLK. 10

LDAC

this pin is tied permanently low, the addressed DAC register is updated on the rising edge of

falling edge of

. The

LDAC

Active Low Input. Asserting this pin sets the DAC registers to zero-scale code or midscale code (user-selectable).

CLR

LDAC

. In this mode, all analog outputs can be updated simultaneously on the falling edge of

LDAC

pin must not be left unconnected.

14 DVCC Digital Supply. Voltage ranges from 2.7 V to 5.5 V. 15 GND Ground Reference. 16 SDO Serial Data Output. Used to clock data from the serial register in daisy-chain or readback mode. Data is

clocked out on the rising edge of SCLK and is valid on the falling edge of SCLK. 17 REFIN 18, 19 DAC_GND Ground Reference for the Four Digital-to-Analog Converters. 20, 21 SIG_GND Ground Reference for the Four Output Amplifiers. 22 V 23 V 24 AVDD Positive Analog Supply. Voltage ranges from 4.5 V to 16.5 V. Exposed

Paddle

D Analog Output Voltage of DAC D. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.

OUT

C Analog Output Voltage of DAC C. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.

OUT

AVSS This exposed paddle can be connected to the potential of the AVSS pin, or alternatively, it can be left electrically

unconnected. It is recommended that the paddle be thermally connected to a copper plane for enhanced thermal

performance.

Rev. F | Page 9 of 31

is low, data is

SYNC

. If

LDAC

Page 10

AD5724/AD5734/AD5754 Data Sheet

CODE

INL ERROR (LSB)

0 10,000

20,000 30,000

40,000

50,000 60,000

–8

–6

–4

–2

AVDD/AV

= +12V/0V, RANGE = +10V

/AV

= ±12V, RANGE = ±10V

/AV

= ±6.5V, RANG E = ±5V

/AV

= +6.5V/0V, RANGE = +5V

06468-013

–2.0

–1.5

–1.0

–0.5

0.5

1.0

1.5

CODE

INL ERROR (LSB)

/AVSS = +12V/0V, RANGE = +10V AVDD/AVSS = ±12V, RANGE = ±10V AVDD/AVSS = ±6.5V, RANG E = ±5V AVDD/AVSS = +6.5V/0V, RANGE = +5V

0 2000 4000

6000 8000 10,000 12,000 14,000 16,000

06468-014

–0.5

–0.4

–0.3

–0.2

–0.1

0.1

0.2

0.3

0 500 1000 1500 2000 2500 3000 3500 4000

CODE

INL ERROR (LSB)

AVDD/AVSS = +12V/0V, RANGE = +10V AV

/AVSS = ±12V, RANGE = ±10V AVDD/AVSS = ±6.5V, RANG E = ±5V AVDD/AVSS = +6.5V/0V, RANGE = +5V

06468-015

CODE

DNL ERROR (LS B)

AVDD/AVSS = +12V/0V, RANGE = +10V AVDD/AVSS = ±12V, RANGE = ±10V AV

/AVSS = ±6.5V, RANG E = ±5V

AVDD/AVSS = +6.5V/0V, RANGE = +5V

0 10,000 20,000 30,000 40000 50,000 60,000

–0.8

–0.6

–0.4

–0.2

0.2

0.4

0.6

06468-016

–0.20

–0.15

–0.10

–0.05

0.05

0.10

0.15

CODE

DNL ERROR (L S B)

/AVSS = +12V/0V, RANGE = +10V

AVDD/AV

= ±12V, RANGE = ±10V AVDD/AVSS = ±6.5V, RANG E = ±5V AV

/AVSS = +6.5V/0V, RANGE = +5V

0 2000 4000 6000

8000 10000 12000 14000 16000

06468-017

–0.05

–0.04

–0.03

–0.02

–0.01

0.01

0.02

0.03

0.04

0 500 1000 1500

2000 2500 3000 3500 4000

AVDD/AVSS = +12V/0V, RANGE = +10V AVDD/AVSS = ±12V, RANGE = ±10V AV

/AVSS = ±6.5V, RANG E = ±5V

AVDD/AV

= +6.5V/0V, RANGE = +5V

CODE

DNL ERROR (L S B)

06468-018

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 6. AD5754 INL Error vs. Code

Figure 7. AD5734 INL Error vs. Code

Figure 9. AD5754 DNL Error vs. Code

Figure 10. AD5734 DNL Error vs. Code

Figure 8. AD5724 INL Error vs. Code

Figure 11. AD5724 DNL Error vs. Code

Rev. F | Page 10 of 31

Page 11

Data Sheet AD5724/AD5734/AD5754

TEMPERATURE (°C)

INL ERROR ( LSB)

–8

–6

–4

–2

–40 –20 0 20 40 60 80

MAX INL ±10V MAX INL ±5V MIN INL ±10V MIN INL ±5V MAX INL +10V MIN INL +10V MAX INL +5V MIN INL +5V

06468-044

–0.6

–0.5

–0.4

–0.3

–0.2

–0.1

0.1

TEMPERATURE (°C)

DNL ERROR (L S B)

–40 –20 0 20 40 60 80

MAX DNL ±10V MAX DNL ±5V MIN DNL ±10V MIN DNL ±5V MAX DNL +10V MIN DNL +10V MAX DNL +5V MIN DNL +5V

06468-045

–10

–8

–6

–4

–2

SUPPLY (V)

INL ERROR ( LSB)

11.5 12.512.0 13.5 14.013.0 14.5 15.0 15.5 16.0 16.5

BIPOLAR 10V M IN UNIPOLAR 10V M IN BIPOLAR 10V M AX UNIPOLAR 10V M AX

06468-034

SUPPLY VOLTAGE (V)

5.5 8.56.5 7.5 10.5 11.59.5 12.5 13.5 14.5 15.5 16.5

–10

–8

–6

–4

–2

INL ERROR ( LSB)

BIPOLAR 5V M IN UNIPOLAR 5V M IN BIPOLAR 5V M AX UNIPOLAR 5V M AX

06468-035

SUPPLY VOLTAGE (V)

DNL ERROR (L S B)

11.5 12.512.0 13.5 14.013.0 14.5 15.0 15.5 16.0 16.5

0.6

0.4

0.2

1.0

0.8

–0.6

–0.4

–0.2

–1.0

–0.8

BIPOLAR 10V M IN UNIPOLAR 10V M IN BIPOLAR 10V M AX UNIPOLAR 10V M AX

06468-032

SUPPLY VOLTAGE (V)

DNL ERROR (L S B)

5.5 8.56.5 7.5 10.5 11.59.5 12.5 13.5 14.5 15.5 16.5

0.6

0.4

0.2

1.0

0.8

–0.6

–0.4

–0.2

–1.0

–0.8

BIPOLAR 5V M IN UNIPOLAR 5V M IN BIPOLAR 5V M AX UNIPOLAR 5V M AX

06468-033

Figure 12. AD5754 INL Error vs. Temperature

Figure 13. AD5754 DNL Error vs. Temperature

Figure 15. AD5754 INL Error vs. Supply Voltage

Figure 16. AD5754 DNL Error vs. Supply Voltage

Figure 14. AD5754 INL Error vs. Supply Voltage

Figure 17. AD5754 DNL Error vs. Supply Voltage

Rev. F | Page 11 of 31

Page 12

AD5724/AD5734/AD5754 Data Sheet

SUPPLY VOLTAGE (V)

11.5 12.512.0 13.5

14.013.0 14.5

15.0

15.5 16.0

16.5

BIPOLAR 10V M IN UNIPOLAR 10V M IN BIPOLAR 10V M AX UNIPOLAR 10V M AX

TUE (%)

–0.04

–0.03

–0.02

–0.01

0.01

0.02

06468-036

SUPPLY VOLTAGE (V)

5.5 8.56.5 7.5 10.5 11.59.5 12.5 13.5 14.5 15.5 16.5

–0.05

–0.04

–0.03

–0.02

–0.01

0.01

0.02

0.03

0.04

TUE (%)

BIPOLAR 5V M IN UNIPOLAR 5V M IN BIPOLAR 5V M AX UNIPOLAR 5V M AX

06468-037

–8

–6

–4

–2

4.5 6.5 8.5 10.5 12.5 14.5 16.5

(mA)

/AVSS (V)

/AI

(mA)

06468-038

(V)

(mA)

4.5 6.5 8.5 10.5 12.5 14.5 16.5

06468-042

–3

–2

–1

TEMPERATURE (°

ZERO-SCALE ERROR (mV)

–40 –20

0 20 40

60 80

±10V

±5V

+10V

06468-046

–1.0

–0.8

–0.6

–0.4

–0.2

0.2

0.4

0.6

0.8

TEMPERATURE (

°C)

BIPOLAR ZERO ERROR (mV )

–40 –20

0 20 40 60

±5V RANGE

±10V RANGE

06468-047

Figure 18. AD5754 TUE vs. Supply Voltage

Figure 19. AD5754 TUE vs. Supply Voltage

Figure 21. Supply Current vs. Supply Voltage (Single Supply)

Figure 22. Zero-Scale Error vs. Temperature

Figure 20. Supply Current vs. Supply Voltage (Dual Supply)

Figure 23. Bipolar Zero Error vs. Temperature

Rev. F | Page 12 of 31

Page 13

Data Sheet AD5724/AD5734/AD5754

–0.06

–0.04

–0.02

0.02

0.04

0.06

±10V

±5V

+10V

TEMPERATURE (

°C)

GAIN ERROR ( % FSR)

–40 –20 0 20 40 60 80

06468-048

LOGIC

(V)

(µA)

–100

100

200

300

400

500

600

700

800

900

1000

0 1 2 3 4

5 6

= 5V

= 3V

06468-043

OUTPUT CURRENT (mA)

OUTPUT VOLTAGE DELTA (V)

–0.020

–0.015

–0.010

–0.005

0.005

0.010

–25 –20 –15 –10 –5 0 5 10 15 20 25

±5V RANGE, CO DE = 0xFFFF ±10V RANGE, CO DE = 0xFFFF +10V RANGE, CO DE = 0xFFFF +5V RANGE, CO DE = 0xFFFF ±5V RANGE, CO DE = 0x0000 ±10V RANGE, CO DE = 0x0000

06468-040

–15

–10

–5

–3

–1 1 3 5 7 9 11

TIME (µs)

OUTPUT VOLTAGE (V)

06468-022

–7

–5

–3

–1

–3 –1

1 3 5

7 9 11

TIME (µs)

OUTPUT VOLTAGE (V)

06468-023

–3 –1 1 3 5 7 9

TIME (µs)

OUTPUT VOLTAGE (V)

06468-024

Figure 24. Gain Error vs. Temperature

Figure 25. Digital Current vs. Logic Input Voltage

Figure 27. Full-Scale Settling Time, ±10 V Range

Figure 28. Full-Scale Settling Time, ±5 V Range

Figure 26. Output Source and Sink Capability

Figure 29. Full-Scale Settling Time, 10 V Range

Rev. F | Page 13 of 31

Page 14

AD5724/AD5734/AD5754 Data Sheet

OUTPUT VOLTAGE (V)

–3 –1 1 3 5 7 9 11

TIME (µs)

Figure 30. Full-Scale Settling Time, +5 V Range

–0.005

OUTPUT VOLTAGE (V)

–0.010

0.020

0.015

0.010

0.005

±10V RANGE, 0x7F FF TO 0x8000 ±10V RANGE, 0x8000 T O 0x7FFF ±5V RANGE, 0x7F FF TO 0x8000 ±5V RANGE, 0x8000 T O 0x7FFF +10V RANGE, 0x7F FF TO 0x8000 +10V RANGE, 0x8000 T O 0x7FFF +5V RANGE, 0x7F FF TO 0x8000 +5V RANGE, 0x8000 T O 0x7FFF

6468-025

RANGE = ±5V RANGE = +5V

RANGE = +10V RANGE = ±10V

CH1 5µV M5s LINE 73.8V

Figure 33. Peak-to-Peak Noise, 100 kHz Bandwidth

OUTPUT VOLTAGE (V)

0.10

0.08

0.06

0.04

0.02

–0.02

–0.04

AVDD/AVSS = ±16.5V

= +16.5V, AVSS = 0V

06468-027

–0.015

–1012345

TIME (µs)

Figure 31. Digital-to-Analog Glitch Energy

RANGE = ±5V RANGE = +5V

CH1 5µV M 5s LINE 73.8V

RANGE = +10V RANGE = ±10V

Figure 32. Peak-to-Peak Noise, 0.1 Hz to 10 Hz Bandwidth

–0.06

–50–30–101030507090

06468-039

TIME (µs)

06468-041

Figure 34. Output Glitch on Power-Up

AVDD/AVSS = +12V/0V, RANGE = +10V

/AVSS = ±12V, RANGE = ±10V

–5

–10

TUE (LSB)

–15

–20

–25

–30

6468-026

–35

/AVSS = ±6.5V, RA NGE = ±5V

/AVSS = +6.5V/0V, RANGE = +5V

0 1000 2000 3000 4000 5000 6000

CODE

06468-019

Figure 35. AD5754 TUE vs. Code

Rev. F | Page 14 of 31

Page 15

Data Sheet AD5724/AD5734/AD5754

–10

–8

–6

–4

–2

2000 4000 6000 8000 10,000 12,000 14,000 16,000

CODE

TUE (LSB)

/AV

= +12V/0V, RANGE = +10V

/AV

= ±12V, RANGE = ±10V

/AV

= ±6.5V, RANG E = ±5V

/AV

= +6.5V/0V, RANGE = +5V

06468-020

–2.5

–2.0

–1.5

–1.0

–0.5

0.5

1.0

0 500

1000 1500 2000 2500 3000 3500 4000

CODE

TUE (LSB)

AVDD/AVSS = +12V/0V, RANGE = +10V AV

/AVSS = ±12V, RANGE = ±10V

/AV

= ±6.5V, RANG E = ±5V

AVDD/AVSS = +6.5V/0V, RANGE = +5V

06468-021

Figure 36. AD5734 TUE vs. Code

Figure 37. AD5724 TUE vs. Code

Rev. F | Page 15 of 31

Page 16

AD5724/AD5734/AD5754 Data Sheet

TERMINOLOGY

Relative Accuracy or Integral Nonlinearity (INL)

For the DAC, relative accuracy, or integral nonlinearity, is a measure of the maximum deviation in LSBs from a straight line passing through the endpoints of the DAC transfer function. A typical INL vs. code plot can be seen in Figure 6.

Differential Nonlinearity (DNL)

Differential nonlinearity is the difference between the measured change and the ideal 1 LSB change between any two adjacent codes. A specified differential nonlinearity of ±1 LSB maximum ensures monotonicity. This DAC is guaranteed monotonic by design. A typical DNL vs. code plot can be seen in Figure 9.

Monotonicity

A DAC is monotonic if the output either increases or remains constant for increasing digital input code. The AD5724/AD5734/

AD5754 are monotonic over the full operating temperature

range of the devices.

Bipolar Zero Error

Bipolar zero error is the deviation of the analog output from the ideal half-scale output of 0 V when the DAC register is loaded with 0x8000 (straight binary coding) or 0x0000 (twos complement coding). A plot of bipolar zero error vs. temperature can be seen in Figure 23.

Bipolar Zero Temperature Coefficient (TC)

Bipolar zero TC is a measure of the change in the bipolar zero error with a change in temperature. It is expressed in ppm FSR/°C.

Zero-Scale Error or Negative Full-Scale Error

Zero-scale error is the error in the DAC output voltage when 0x0000 (straight binary coding) or 0x8000 (twos complement coding) is loaded to the DAC register. Ideally, the output voltage must be negative full-scale −1 LSB. A plot of zero-scale error vs. temperature can be seen in Figure 22.

Zero-Scale TC

Zero-scale TC is a measure of the change in zero-scale error with a change in temperature. Zero-scale TC is expressed in ppm FSR/°C.

Output Voltage Settling Time

Output voltage settling time is the amount of time required for the output to settle to a specified level for a full-scale input change. A plot for full-scale settling time can be seen in Figure 27.

Slew Rate

The slew rate of a device is a limitation in the rate of change of the output voltage. The output slewing speed of a voltage output DAC is usually limited by the slew rate of the amplifier used at the output. Slew rate is measured from 10% to 90% of the output signal and is given in V/µs.

Gain Error

Gain error is a measure of the span error of the DAC. It is the deviation in slope of the DAC transfer characteristic from the ideal and is expressed in % FSR. A plot of gain error vs. temperature can be seen in Figure 24.

Gain TC

Gain TC is a measure of the change in gain error with changes in temperature. Gain TC is expressed in ppm FSR/°C.

Total Unadjusted Error (TUE)

Total unadjusted error is a measure of the output error taking all the various errors into account, namely INL error, offset error, gain error, and output drift over supplies, temperature, and time. TUE is expressed in % FSR.

Digital-to-Analog Glitch Impulse

Digital-to-analog glitch impulse is the impulse injected into the analog output when the input code in the DAC register changes state, but the output voltage remains constant. It is normally specified as the area of the glitch in nV-sec and is measured when the digital input code is changed by 1 LSB at the major carry transition (0x7FFF to 0x8000). See Figure 31.

Glitch Impulse Peak Amplitude

Glitch impulse peak amplitude is the peak amplitude of the impulse injected into the analog output when the input code in the DAC register changes state. It is specified as the amplitude of the glitch in mV and is measured when the digital input code is changed by 1 LSB at the major carry transition (0x7FFF to 0x8000). See Figure 31.

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into the analog output of the DAC from the digital inputs of the DAC, but is measured when the DAC output is not updated. It is specified in nV-sec and measured with a full-scale code change on the data bus.

Power Supply Sensitivity

Power supply sensitivity indicates how the output of the DAC is affected by changes in the power supply voltage. It is measured by superimposing a 50 Hz/60 Hz, 200 mV p-p sine wave on the supply voltages and measuring the proportion of the sine wave that transfers to the outputs.

Rev. F | Page 16 of 31

Page 17

Data Sheet AD5724/AD5734/AD5754

DC Crosstalk

This is the dc change in the output level of one DAC in response to a change in the output of another DAC. It is measured with a full-scale output change on one DAC while monitoring another DAC. It is expressed in LSBs.

Digital Crosstalk

Digital crosstalk is a measure of the impulse injected into the analog output of one DAC from the digital inputs of another DAC, but is measured when the DAC output is not updated. It is specified in nV-sec and measured with a full-scale code change on the data bus.

DAC-to-DAC Crosstalk

DAC-to-DAC crosstalk is the glitch impulse transferred to the output of one DAC due to a digital code change and a subsequent output change of another DAC. This includes both digital and analog crosstalk. It is measured by loading one of the DACs with a full-scale code change (all 0s to all 1s and vice versa) with LDAC

low and monitoring the output of another DAC. The

energy of the glitch is expressed in nV-sec.

Rev. F | Page 17 of 31

Page 18

GND

RESISTOR

STRING

REF (+)

REF (–)

CONFIGURABLE OUTPUT AMPLIFIER

OUTPUT

RANGE CONTROL

06468-006

REFIN

DAC REGIST E R

OUT

TO OUTPUT AMPLIFIER

REFIN

06468-007

AD5724/AD5734/AD5754 Data Sheet

THEORY OF OPERATION

The AD5724/AD5734/AD5754 are quad, 12-/14-/16-bit, serial input, unipolar/bipolar, voltage output DACs. They operate from unipolar supply voltages of +4.5 V to +16.5 V or bipolar supply voltages of ±4.5 V to ±16.5 V. In addition, the devices have software-selectable output ranges of +5 V, + 10 V, +10.8 V, ± 5 V, ±10 V, and ±10.8 V. Data is written to the AD5724/AD5734/

AD5754 in a 24-bit word format via a 3-wire serial interface.

The devices also offer an SDO pin to facilitate daisy-chaining or readback.

The AD5724/AD5734/AD5754 incorporate a power-on reset circuit to ensure that the DAC registers power up loaded with 0x0000. When powered on, the outputs are clamped to 0 V via a low impedance path.

ARCHITECTURE

The DAC architecture consists of a string DAC followed by an output amplifier. Figure 38 shows a block diagram of the DAC architecture. The reference input is buffered before being applied to the DAC.

Figure 38. DAC Architecture Block Diagram

The resistor string structure is shown in Figure 39. It is a string of resistors, each of value R. The code loaded to the DAC register determines the node on the string where the voltage is to be tapped off and fed into the output amplifier. The voltage is tapped off by closing one of the switches connecting the string to the amplifier. Because it is a string of resistors, it is guaranteed monotonic.

Output Amplifiers

The output amplifiers are capable of generating both unipolar and bipolar output voltages. They are capable of driving a load of 2 kΩ in parallel with 4000 pF to GND. The source and sink capabilities of the output amplifiers can be seen in Figure 26. The slew rate is 3.5 V/µs with a full-scale settling time of 10 µs.

Reference Buffers

The AD5724/AD5734/AD5754 require an external reference source. The reference input has an input range of 2 V to 3 V, with 2.5 V for specified performance. This input voltage is then buffered before it is applied to the DAC cores.

POWER-UP SEQUENCE

Because the DAC output voltage is controlled by the voltage monitor and control block (see Figure 42), it is important to power the DV and AV

pin before applying any voltage to the AVDD

pins; otherwise, the G1 and G2 transmission gates are at an undefined state. The ideal power-up sequence is in the following order: GND, SIG_GND, DAC_GND, DV AV

, and then the digital inputs. The relative order of powering

and AVSS is not important, provided that they are powered

up after DV

, AVDD,

SERIAL INTERFACE

The AD5724/AD5734/AD5754 are controlled over a versatile 3-wire serial interface that operates at clock rates up to 30 MHz. It is compatible with SPI, QSPI™, MICROWIRE™, and DSP standards.

Input Shift Register

The input shift register is 24 bits wide. Data is loaded into the device MSB first as a 24-bit word under the control of a serial clock input, SCLK. The input register consists of a read/write bit, three register select bits, three DAC address bits, and 16 data bits. The timing diagram for this operation is shown in Figure 2.

Figure 39. Resistor String Structure

Rev. F | Page 18 of 31

Page 19

ADDITIONAL PINS OMITTED FOR CLARITY.

68HC11

MISO

SDIN SCLK

MOSI

SCK

PC7 PC6

SDO

SCLK

SDO

SCLK

SDO

SDIN

SYNC

SYNC LDAC

LDAC

AD5724/ AD5734/

AD5754*

AD5724/ AD5734/

AD5754*

AD5724/ AD5734/

AD5754*

06468-008

Data Sheet AD5724/AD5734/AD5754

Standalone Operation

The serial interface works with both a continuous and noncontinuous serial clock. A continuous SCLK source can be used

SYNC

only if

is held low for the correct number of clock cycles.

In gated clock mode, a burst clock containing the exact number

SYNC

of clock cycles must be used and

must be taken high after the final clock to latch the data. The first falling edge of starts the write cycle. Exactly 24 falling clock edges must be

SYNC

applied to SCLK before brought high before the 24

is brought high again. If

falling SCLK edge, the data written is invalid. If more than 24 falling SCLK edges are applied before SYNC

is brought high, the input data is also invalid. The input

SYNC

another serial transfer to take place,

must be brought low

SYNC

again. After the end of the serial data transfer, data is automatically transferred from the input shift register to the addressed register.

When the data has been transferred into the chosen register of the addressed DAC, all DAC registers and outputs can be updated by taking

LDAC

low while

Figure 40. Daisy Chaining the AD5724/AD5734/AD5754

SYNC

is high.

SYNC

. For

Daisy-Chain Operation

For systems that contain several devices, the SDO pin can be used to daisy-chain several devices together. Daisy-chain mode can be useful in system diagnostics and in reducing the number of serial interface lines. The first falling edge of

SYNC

starts the

write cycle. SCLK is continuously applied to the input shift

SYNC

is low. If more than 24 clock pulses are applied, the data ripples out of the shift register and appears on the SDO line. This data is clocked out on the rising edge of SCLK and is valid on the falling edge. By connecting the SDO of the first device to the SDIN input of the next device in the chain, a multidevice 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

AD5724/AD5734/AD5754 devices in the chain. When the serial

SYNC

transfer to all devices is complete,

is taken high. This latches the input data in each device in the daisy chain and prevents any further data from being clocked into the input shift register. The serial clock can be a continuous or a gated clock.

A continuous SCLK source can only be used if

SYNC

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

SYNC

must be taken high after the final clock to

latch the data.

Readback Operation

Readback mode is invoked by setting the R/W bit = 1 in the serial input shift register write. (If the SDO output is disabled via the SDO disable bit in the control register, it is automatically enabled for the duration of the read operation, after which it is disabled again). With R/

= 1, Bit A2 to Bit A0 in association with Bit REG2 to Bit REG0, select the register to be read. The remaining data bits in the write sequence are don’t care bits. During the next SPI write, the data appearing on the SDO output contains the data from the previously addressed register. For a read of a single register, the NOP command can clock out the data from the selected register on SDO. The readback diagram in

Figure 4 shows the readback sequence. For example, to read back the DAC register of Channel A, the following sequence must be implemented:

1. Write 0x800000 to the AD5724/AD5734/AD5754 input

register. This configures the device for read mode with the DAC register of Channel A selected. Note that all the data bits, DB15 to DB0, are don’t care bits.

2. Follow this with a second write, a NOP condition, 0x180000.

During this write, the data from the register is clocked out on the SDO line.

Rev. F | Page 19 of 31

Page 20

SYNC

SCLK

OUT

DAC

INTERFACE

LOGIC

OUTPUT

AMPLIFIER

LDAC

SDO

SDIN

REFIN

INPUT

12-/14-/16-BIT

DAC

06468-009













×=

REFIN

OUT

GainVV

REFIN

OUT

VGain

GainVV

−













±10.8

8.64

AD5724/AD5734/AD5754 Data Sheet

LOAD DAC (

LDAC

)

After data has been transferred into the input register of the DACs, there are two ways to update the DAC registers and DAC outputs. Depending on the status of both

SYNC

and

LDAC

, one of two update modes is selected: individual DAC updating or simultaneous updating of all DACs.

Figure 41. Simplified Diagram of Input Loading Circuitry for One DAC

Individual DAC Updating

In this mode,

LDAC

is held low while data is being clocked into

the input shift register. The addressed DAC output is updated

SYNC

on the rising edge of

Simultaneous Updating of All DACs

In this mode,

LDAC

is held high while data is being clocked

into the input shift register. All DAC outputs are asynchronously

LDAC

updated by taking

low after

The update now occurs on the falling edge of

ASYNCHRONOUS CLEAR (

CLR

is an active low clear that allows the outputs to clear to

SYNC

CLR

has been taken high.

LDAC

)

either zero-scale code or midscale code. The clear code value is user-selectable via the CLR select bit of the control register (see the Control Register section). It is necessary to maintain

CLR

low for a minimum amount of time to complete the operation (see Figure 2). When the

CLR

signal is returned high, the output

remains at the cleared value until a new value is programmed.

CLR

The outputs cannot update with a new value while the

pin is low. A clear operation can also be performed via the clear command in the control register.

CONFIGURING THE AD5724/AD5734/AD5754

When the power supplies are applied to the AD5724/AD5734/

AD5754, the power-on reset circuit ensures that all registers

default to 0. This places all channels in power-down mode.

The DV are powered. If this is not done, the first write to the device may be ignored. The first communication to the AD5724/AD5734/

AD5754 must be to set the required output range on all channels

(the default range is the 5 V unipolar range) by writing to the output range select register. The user must then write to the power control register to power on the required channels. To program an output value on a channel, that channel must first be powered up; any writes to a channel while it is in power-down mode are ignored. The AD5724/AD5734/AD5754 operate with a wide power supply range. It is important that the power supply applied to the devices provides adequate headroom to support the chosen output ranges.

TRANSFER FUNCTION

Tabl e 7 to Tab l e 15 show the relationships of the ideal input code to output voltage for the AD5754, AD5734, and AD5724, respec- tively, for all output voltage ranges. For unipolar output ranges, the data coding is straight binary. For bipolar output ranges, the data coding is user-selectable via the BIN/ be either offset binary or twos complement.

For a unipolar output range, the output voltage expression is given by

For a bipolar output range, the output voltage expression is given by

where:

D is the decimal equivalent of the code loaded to the DAC. N is the bit resolution of the DAC. V

REFIN

Gain is an internal gain with a value that depends on the output

range selected by the user, as shown in Table 6.

Table 6. Internal Gain Values

Output Range (V) Gain Value

+5 2 +10 4 +10.8 4.32 ±5 4 ±10 8

must be brought high before any of the interface lines

2sCOMP

pin and can

is the reference voltage applied at the REFIN pin.

Rev. F | Page 20 of 31

Page 21

Data Sheet AD5724/AD5734/AD5754

0000

0001

−2 × REFIN × (32,767/32,768)

−4 × REFIN × (32,767/32,768)

−4.32 × REFIN × (32,767/32,768)

0000

−2 × REFIN × (32,768/32,768)

−4 × REFIN × (32,768/32,768)

−4.32 × REFIN × (32,768/32,768)

0000

0001

+2 × REFIN × (1/32,768)

+4 × REFIN × (1/32,768)

+4.32 × REFIN × (1/32,768)

Digital Input

Analog Output

1000

0000

+2 × REFIN × (32,768/65,536)

+4 × REFIN × (32,768/65,536)

+4.32 × REFIN × (32,768/65,536)

Ideal Output Voltage to Input Code Relationship—AD5754

Table 7. Bipolar Output, Offset Binary Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

1111 1111 1111 1111 +2 × REFIN × (32,767/32,768) +4 × REFIN × (32,767/32,768) +4.32 × REFIN × (32,767/32,768) 1111 1111 1111 1110 +2 × REFIN × (32,766/32,768) +4 × REFIN × (32,766/32,768) +4.32 × REFIN × (32,766/32,768) … … … … … … … 1000 0000 0000 0001 +2 × REFIN × (1/32,768) +4 × REFIN × (1/32,768) +4.32 × REFIN × (1/32,768) 1000 0000 0000 0000 0 V 0 V 0 V 0111 1111 1111 1111 −2 × REFIN × (1/32,768) −4 × REFIN × (1/32,768) −4.32 × REFIN × (32,766/32,768) … … … … … … …

Table 8. Bipolar Output, Twos Complement Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

0111 1111 1111 1111 +2 × REFIN × (32,767/32,768) +4 × REFIN × (32,767/32,768) +4.32 × REFIN × (32,767/32,768) 0111 1111 1111 1110 +2 × REFIN × (32,766/32,768) +4 × REFIN × (32,766/32,768) +4.32 × REFIN × (32,766/32,768) … … … … … … …

0000 0000 0000 0000 0 V 0 V 0 V 1111 1111 1111 1111 −2 × REFIN × (1/32,768) −4 × REFIN × (1/32,768) −4.32 × REFIN × (1/32,768) … … … … … … … 1000 0000 0000 0001 −2 × REFIN × (32,767/32,768) −4 × REFIN × (32,767/32,768) −4.32 × REFIN × (32,767/32,768) 1000 0000 0000 0000 −2 × REFIN × (32,768/32,768) −4 × REFIN × (32,768/32,768) −4.32 × REFIN × (32,768/32,768)

Table 9. Unipolar Output, Straight Binary Coding

MSB LSB +5 V Output Range +10 V Output Range +10.8 V Output Range

1111 1111 1111 1111 +2 × REFIN × (65,535/65,536) +4 × REFIN × (65,535/65,536) +4.32 × REFIN × (65,535/65,536) 1111 1111 1111 1110 +2 × REFIN × (65,534/65,536) +4 × REFIN × (65,534/65,536) +4.32 × REFIN × (65,534/65,536) … … … … … … … 1000 0000 0000 0001 +2 × REFIN × (32,769/65,536) +4 × REFIN × (32,769/65,536) +4.32 × REFIN × (32,769/65,536)

0111 1111 1111 1111 +2 × REFIN × (32,767/65,536) +4 × REFIN × (32,767/65,536) +4.32 × REFIN × (32,767/65,536) … … … … … … … 0000 0000 0000 0001 +2 × REFIN × (1/65,536) +4 × REFIN × (1/65,536) +4.32 × REFIN × (1/65,536) 0000 0000 0000 0000 0 V 0 V 0 V

Rev. F | Page 21 of 31

Page 22

AD5724/AD5734/AD5754 Data Sheet

0000

0001

−2 × REFIN × (8191/8192)

−4 × REFIN × (8191/8192)

−4.32 × REFIN × (8191/8192)

0000

−2 × REFIN × (8192/8192)

−4 × REFIN × (8192/8192)

−4.32 × REFIN × (8192/8192)

0000

0001

+2 × REFIN × (1/8192)

+4 × REFIN × (1/8192)

+4.32 × REFIN × (1/8192)

Digital Input

Analog Output

0000

+2 × REFIN × (8192/16,384)

+4 × REFIN × (8192/16,384)

+4.32 × REFIN × (8192/16,384)

Ideal Output Voltage to Input Code Relationship—AD5734

Table 10. Bipolar Output, Offset Binary Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

11 1111 1111 1111 +2 × REFIN × (8191/8192) +4 × REFIN × (8191/8192) +4.32 × REFIN × (8191/8192) 11 1111 1111 1110 +2 × REFIN × (8190/8192) +4 × REFIN × (8190/8192) +4.32 × REFIN × (8190/8192) … … … … … … … 10 0000 0000 0001 +2 × REFIN × (1/8192) +4 × REFIN × (1/8192) +4.32 × REFIN × (1/8192) 10 0000 0000 0000 0 V 0 V 0 V 01 1111 1111 1111 −2 × REFIN × (1/8192) −4 × REFIN × (1/8192) −4.32 × REFIN × (1/8192) … … … … … … …

Table 11. Bipolar Output, Twos Complement Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

01 1111 1111 1111 +2 × REFIN × (8191/8192) +4 × REFIN × (8191/8192) +4.32 × REFIN × (8191/8192) 01 1111 1111 1110 +2 × REFIN × (8190/8192) +4 × REFIN × (8190/8192) +4.32 × REFIN × (8190/8192) … … … … … … …

00 0000 0000 0000 0 V 0 V 0 V 11 1111 1111 1111 −2 × REFIN × (1/8192) −4 × REFIN × (1/8192) −4.32 × REFIN × (1/8192) … … … … … … … 10 0000 0000 0001 −2 × REFIN × (8191/8192) −4 × REFIN × (8191/8192) −4.32 × REFIN × (8191/8192) 10 0000 0000 0000 −2 × REFIN × (8192/8192) −4 × REFIN × (8192/8192) −4.32 × REFIN × (8192/8192)

Table 12. Unipolar Output, Straight Binary Coding

MSB LSB +5 V Output Range +10 V Output Range +10.8 V Output Range

11 1111 1111 1111 +2 × REFIN × (16,383/16,384) +4 × REFIN × (16,383/16,384) +4.32 × REFIN × (16,383/16,384) 11 1111 1111 1110 +2 × REFIN × (16,382/16,384) +4 × REFIN × (16,382/16,384) +4.32 × REFIN × (16,382/16,384) … … … … … … … 10 0000 0000 0001 +2 × REFIN × (8193/16,384) +4 × REFIN × (8193/16,384) +4.32 × REFIN × (8193/16,384)

01 1111 1111 1111 +2 × REFIN × (8191/16,384) +4 × REFIN × (8191/16,384) +4.32 × REFIN × (8191/16,384) … … … … … … … 00 0000 0000 0001 +2 × REFIN × (1/16,384) +4 × REFIN × (1/16,384) +4.32 × REFIN × (1/16,384) 00 0000 0000 0000 0 V 0 V 0 V

Rev. F | Page 22 of 31

Page 23

Data Sheet AD5724/AD5734/AD5754

0000

0001

−2 × REFIN × (2047/2048)

−4 × REFIN × (2047/2048)

−4.32 × REFIN × (2047/2048)

0000

−2 × REFIN × (2048/2048)

−4 × REFIN × (2048/2048)

−4.32 × REFIN × (2048/2048)

0000

0001

+2 × REFIN × (1/2048)

+4 × REFIN × (1/2048)

+4.32 × REFIN × (1/2048)

Digital Input

Analog Output

1000

0000

+2 × REFIN × (2048/4096)

+4 × REFIN × (2048/4096)

+4.32 × REFIN × (2048/4096)

Ideal Output Voltage to Input Code Relationship—AD5724

Table 13. Bipolar Output, Offset Binary Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

1111 1111 1111 +2 × REFIN × (2047/2048) +4 × REFIN × (2047/2048) +4.32 × REFIN × (2047/2048) 1111 1111 1110 +2 × REFIN × (2046/2048) +4 × REFIN × (2046/2048) +4.32 × REFIN × (2046/2048) … … … … … … 1000 0000 0001 +2 × REFIN × (1/2048) +4 × REFIN × (1/2048) +4.32 × REFIN × (1/2048) 1000 0000 0000 0 V 0 V 0 V 0111 1111 1111 −2 × REFIN × (1/2048) −4 × REFIN × (1/2048) −4.32 × REFIN × (1/2048) … … … … … …

Table 14. Bipolar Output, Twos Complement Coding

Digital Input Analog Output

MSB LSB ±5 V Output Range ±10 V Output Range ±10.8 V Output Range

0111 1111 1111 +2 × REFIN × (2047/2048) +4 × REFIN × (2047/2048) +4.32 × REFIN × (2047/2048) 0111 1111 1110 +2 × REFIN × (2046/2048) +4 × REFIN × (2046/2048) +4.32 × REFIN × (2046/2048) … … … … … …

0000 0000 0000 0 V 0 V 0 V 1111 1111 1111 −2 × REFIN × (1/2048) −4 × REFIN × (1/2048) −4.32 × REFIN × (1/2048) … … … … … … 1000 0000 0001 −2 × REFIN × (2047/2048) −4 × REFIN × (2047/2048) −4.32 × REFIN × (2047/2048) 1000 0000 0000 −2 × REFIN × (2048/2048) −4 × REFIN × (2048/2048) −4.32 × REFIN × (2048/2048)

Table 15. Unipolar Output, Straight Binary Coding

MSB LSB +5 V Output Range +10 V Output Range +10.8 V Output Range

1111 1111 1111 +2 × REFIN × (4095/4096) +4 × REFIN × (4095/4096) +4.32 × REFIN × (4095/4096) 1111 1111 1110 +2 × REFIN × (4094/4096) +4 × REFIN × (4094/4096) +4.32 × REFIN × (4094/4096) … … … … … … 1000 0000 0001 +2 × REFIN × (2049/4096) +4 × REFIN × (2049/4096) +4.32 × REFIN × (2049/4096)

0111 1111 1111 +2 × REFIN × (2047/4096) +4 × REFIN × (2047/4096) +4.32 × REFIN × (2047/4096) … … … … … … 0000 0000 0001 +2 × REFIN × (1/4096) +4 × REFIN × (1/4096) +4.32 × REFIN × (1/4096) 0000 0000 0000 0 V 0 V 0 V

Rev. F | Page 23 of 31

Page 24

AD5724/AD5734/AD5754 Data Sheet

0 0 0 DAC A

R/W

Zero

REG2

REG1

REG0

DB15 to DB2

DB1

DB0

INPUT SHIFT REGISTER

The input shift register is 24 bits wide and consists of a read/write bit (R/W), a reserved bit (zero) that must always be set to 0, three register select bits (REG0, REG1, REG2), three DAC address bits (A2, A1, A0), and 16 data bits (data). The register data is clocked in MSB first on the SDIN pin. Tabl e 16 shows the register format and Tab l e 17 describes the function of each bit in the register. All registers are read/write registers.

Table 16. Input Register Format

MSB LSB DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 to DB0

R/W Zero REG2 REG1 REG0 A2 A1 A0 Data

Table 17. Input Register Bit Functions

Bit Mnemonic Description

R/W Indicates a read from or a write to the addressed register. REG2, REG1, REG0 Used in association with the address bits to determine if a write operation is to the DAC register, the output range

select register, the power control register, or the control register.

0 0 0 DAC register 0 0 1 Output range select register 0 1 0 Power control register 0 1 1 Control register A2, A1, A0 These DAC address bits are used to decode the DAC channels.

REG2 REG1 REG0 Function

A2 A1 A0 Channel Address

0 0 1 DAC B 0 1 0 DAC C 0 1 1 DAC D 1 0 0 All four DACs DB15 to DB0 Data bits.

DAC REGISTER

The DAC register is addressed by setting the three REG bits to 000. The DAC address bits select the DAC channel where the data transfer is to take place (see Tab l e 17). The data bits are in positions DB15 to DB0 for the AD5754 (see Table 18), DB15 to DB2 for the AD5734 (see Tabl e 19), and DB15 to DB4 for the AD5724 (see Tabl e 20).

Table 18. Programming the AD5754 DAC Register

MSB LSB

Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB0

0 0 0 0 0 DAC address 16-bit DAC data

Table 19. Programming the AD5734 DAC Register

MSB LSB

0 0 0 0 0 DAC address 14-bit DAC data X X

Table 20. Programming the AD5724 DAC Register

MSB LSB

Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB4 DB3 DB2 DB1 DB0

0 0 0 0 0 DAC address 12-bit DAC data X X X X

Rev. F | Page 24 of 31

Page 25

Data Sheet AD5724/AD5734/AD5754

0 0 1

+10

Option

Description

OUTPUT RANGE SELECT REGISTER

The output range select register is addressed by setting the three REG bits to 001. The DAC address bits select the DAC channel and the range bits (R2, R1, R0) select the required output range (see Table 21 and Tab l e 22).

Table 21. Programming the Required Output Range

MSB LSB

Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB3 DB2 DB1 DB0

0 0 0 0 1 DAC address Don’t care R2 R1 R0

Table 22. Output Range Options

R2 R1 R0 Output Range (V)

0 0 0 +5

0 1 0 +10.8 0 1 1 ±5 1 0 0 ±10 1 0 1 ±10.8

CONTROL REGISTER

The control register is addressed by setting the three REG bits to 011. The value written to the address and data bits determines the control function selected. The control register options are shown in Tabl e 23 and Table 24.

Table 23. Programming the Control Register

MSB LSB

Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB4 DB3 DB2 DB1 DB0

0 0 0 1 1 0 0 0 NOP, data = don’t care 0 0 0 1 1 0 0 1 Don’t care TSD enable Clamp enable CLR select SDO disable 0 0 0 1 1 1 0 0 Clear, data = don’t care 0 0 0 1 1 1 0 1 Load, data = don’t care

Table 24. Explanation of Control Register Options

NOP No operation instruction used in readback operations. Clear Addressing this function sets the DAC registers to the clear code and updates the outputs. Load Addressing this function updates the DAC registers and, consequently, the DAC outputs. SDO Disable Set by the user to disable the SDO output. Cleared by the user to enable the SDO output (default). CLR Select See Table 25 for a description of the CLR select operation. Clamp Enable Set by the user to enable the current-limit clamp. The channel does not power down upon detection of an

overcurrent; the current is clamped at 20 mA (default). Cleared by the user to disable the current-limit clamp. The channel powers down upon detection of an overcurrent.

TSD Enable Set by the user to enable the thermal shutdown feature. Cleared by the user to disable the thermal shutdown

feature (default).

Table 25. CLR Select Options

Output CLR Value CLR Select Setting Unipolar Output Range Bipolar Output Range

0 0 V 0 V 1 Midscale Negative full scale

Rev. F | Page 25 of 31

Page 26

AD5724/AD5734/AD5754 Data Sheet

POWER CONTROL REGISTER

The power control register is addressed by setting the three REG bits to 010. This register allows the user to control and determine the power and thermal status of the AD5724/AD5734/AD5754. The power control register options are shown in Tab l e 26 and Table 27.

Table 26. Programming the Power Control Register

MSB LSB

Zero REG2 REG1 REG0 A2 A1 A0

0 0 0 1 0 0 0 0 X OCD OCC OCB OCA 0 TSD 0 PUD PUC PUB PUA

Table 27. Power Control Register Functions

Option Description

PUA DAC A power-up. When set, this bit places DAC A in normal operating mode. When cleared, this bit places DAC A in power-down

mode (default). After setting this bit to power DAC A, a power up time of 10 µs is required. During this power-up time, the DAC register must not be loaded to the DAC output (see the Load DAC/

cleared, DAC A powers down automatically upon detection of an overcurrent, and PU

PUB DAC B power-up. When set, this bit places DAC B in normal operating mode. When cleared, this bit places DAC B in power-down

mode (default). After setting this bit to power DAC B, a power up time of 10 µs is required. During this power-up time, the DAC register must not be loaded to the DAC output (see the Load DAC/ cleared, DAC B powers down automatically upon detection of an overcurrent, and PUB is cleared to reflect this.

PUC DAC C power-up. When set, this bit places DAC C in normal operating mode. When cleared, this bit places DAC C in power-down

mode (default). After setting this bit to power DAC C, a power up time of 10 µs is required. During this power-up time, the DAC register must not be loaded to the DAC output (see the Load DAC/ cleared, DAC C powers down automatically upon detection of an overcurrent, and PUC is cleared to reflect this.

PUD DAC D power-up. When set, this bit places DAC D in normal operating mode. When cleared, this bit places DAC D in power-down

mode (default). After setting this bit to power DAC D, a power up time of 10 µs is required. During this power-up time, the DAC register must not be loaded to the DAC output (see the Load DAC/ cleared, DAC D powers down automatically upon detection of an overcurrent, and PU

TSD Thermal shutdown alert. Read-only bit. In the event of an overtemperature situation, the four DACs are powered down and this

bit is set. OCA DAC A overcurrent alert. Read-only bit. In the event of an overcurrent situation on DAC A, this bit is set. OCB DAC B overcurrent alert. Read-only bit. In the event of an overcurrent situation on DAC B, this bit is set. OCC DAC C overcurrent alert. Read-only bit. In the event of an overcurrent situation on DAC C, this bit is set. OCD DAC D overcurrent alert. Read-only bit. In the event of an overcurrent situation on DAC D, this bit is set.

DB15 to DB11

DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

section). If the clamp enable bit of the control register is

LDAC

is cleared to reflect this.

section). If the clamp enable bit of the control register is

LDAC

section). If the clamp enable bit of the control register is

LDAC

section). If the clamp enable bit of the control register is

LDAC

is cleared to reflect this.

Rev. F | Page 26 of 31

Page 27

Data Sheet AD5724/AD5734/AD5754

FEATURES

ANALOG OUTPUT CONTROL

In many industrial process control applications, it is vital to control the output voltage during power-up. When the supply voltages change during power-up, the V

x pins are clamped to 0 V via

OUT

a low impedance path (approximately 4 kΩ). To prevent the output amplifiers from being shorted to 0 V during this time, Transmission Gate G1 is also opened (see Figure 42). These conditions are maintained until the analog power supplies have stabilized and a valid word is written to a DAC register. At this time, G2 opens and G1 closes.

VOLTAGE MONITOR

AND

CONTROL

Figure 42. Analog Output Control Circuitry

OUT

6468-010

POWER-DOWN MODE

Each DAC channel of the AD5724/AD5734/AD5754 can be individually powered down. By default, all channels are in powerdown mode. The power status is controlled by the power control register (see Table 26 and Table 27 for details). When a channel is in power-down mode, the output pin is clamped to ground through a resistance of approximately 4 kΩ and the output of the amplifier is disconnected from the output pin.

OVERCURRENT PROTECTION

Each DAC channel of the AD5724/AD5734/AD5754 incorporates individual overcurrent protection. The user has two options for the configuration of the overcurrent protection: constant current clamp or automatic channel power-down. The configuration of the overcurrent protection is selected via the clamp enable bit in the control register.

Constant Current Clamp (Clamp Enable = 1)

If a short circuit occurs in this configuration, the current is clamped at 20 mA. This event is signaled to the user by the setting of the appropriate overcurrent (OC

) bit in the power

control register. Upon removal of the short-circuit fault, the

bit is cleared.

Automatic Channel Power-Down (Clamp Enable = 0)

If a short circuit occurs in this configuration, the shorted channel powers down and the output is clamped to ground via a resistance of approximately 4 kΩ. At this time, the output of the amplifier is disconnected from the output pin. The short-circuit event is signaled to the user via the overcurrent (OC the power-up (PU

) bits indicate which DACs have powered

) bits, and

down. After the fault is rectified, the channels can be powered up again by setting the PU

bits.

THERMAL SHUTDOWN

The AD5724/AD5734/AD5754 incorporate a thermal shutdown feature that automatically shuts down the device if the core temperature exceeds approximately 150°C. The thermal shutdown feature is disabled by default and can be enabled via the TSD enable bit of the control register. In the event of a thermal shutdown, the TSD bit of the power control register is set.

Rev. F | Page 27 of 31

Page 28

AD5724/AD5734/AD5754 Data Sheet

APPLICATIONS INFORMATION

+5 V/±5 V OPERATION

When operating from a single +5 V supply or a dual ±5 V supply, an output range of +5 V or ±5 V is not achievable because sufficient headroom for the output amplifier is not available. In this situation, a reduced reference voltage can be used. For example, a 2 V reference voltage produces an output range of +4 V or ±4 V, and the 1 V of headroom is more than enough for full operation. A standard value voltage reference of 2.048 V can be used to produce output ranges of +4.096 V and ±4.096 V.

ALTERNATIVE POWER-UP SEQUENCE SUPPORT

There may be cases where it is not possible to use the recommended power-up sequence, and in those instances an external circuit shown in Figure 43 is recommended to be used. The circuit shown in Figure 43 ensures that the digital block is powered up first, prior to the analog block, by using a load switch circuit. This circuit targets applications for which either AV

or AVSS or both supplies power up before DVCC.

Consider the following design rules when choosing the component values for the AV

 R1 ensures that the Q1 gate to source voltage is zero when

is in an open state. R1 also prevents false turn on of

Q1. However, if DV source, R1 can be removed to conserve power.

 Select Q1 (N-channel MOSFET) with a V

is much lower than the minimum operating DV V

rating much lower than the maximum operating AVDD.

 C1, R2, and R3 are the main components that dictates the

delay from DV

enable to AVDD. Adjust the values

according for the desired delay. Choose R2 and R3 values that ensure Q2 turn on.

DELAY



where



Q2 (P-channel MOSFET) acts as a switch that allows the flow

of current from V with very low R

AVV

DSON

operation. Other parameters such as maximum V maximum drain to source current rating, V voltage, and maximum gate to source voltage rating must also be taken into consideration when choosing Q2.

LOAD SWITCH

SECTION

CONTROL

SECTION

Figure 43. Load Switch Control Circuit

delay circuit.

is permanently connected to the

threshold that

and a

 

RRCt 1ln)||()sec(

231



 











  



























to AVDD; therefore, choosing a MOSFET

is necessary to minimize losses during

rating,

threshold

06468-143

Rev. F | Page 28 of 31

Figure 44 shows an example of the analog supplies powering up before the digital supply. The circuit delays the AV until after DV

, as shown by the AVDD (delayed) line.

AVDD(DELAYED)

Figure 44. Delayed Power Supplies Sequence Example

t (sec)

power up

6468-144

LAYOUT GUIDELINES

In any circuit where accuracy is important, careful consideration of the power supply and ground return layout helps to ensure the rated performance. The printed circuit board on which the

AD5724/AD5734/AD5754 are mounted must be designed so the

analog and digital sections are separated and confined to certain areas of the board. If the AD5724/AD5734/AD5754 are in a system where multiple devices require an AGND to DGND connection, the connection must be made at one point only. The star ground point must be established as close as possible to the device.

The AD5724/AD5734/AD5754 must have ample supply bypassing of a 10 μF capacitor in parallel with a 0.1 μF capacitor on each supply located as close to the package as possible, ideally right up against the device. The 10 μF capacitor is the tantalum bead type. The 0.1 μF capacitor must have low effective series resistance (ESR) and low effective series inductance (ESI), such as the common ceramic types, which provide a low impedance path to ground at high frequencies to handle transient currents due to internal logic switching.

The power supply lines of the AD5724/AD5734/AD5754 must use as large a trace as possible to provide low impedance paths and reduce the effects of glitches on the power supply line. Fast switching signals, such as a data clock, must be shielded with digital ground to avoid radiating noise to other devices of the board, and must never run near the reference inputs. A ground line routed between the SDIN and SCLK lines helps reduce crosstalk between them (this is not required on a multilayer board that has a separate ground plane, but separating the lines does help). It is essential to minimize noise on the REFIN line because any unwanted signals couple through to the DAC outputs.

Avoid crossover of digital and analog signals. Traces on opposite sides of the board must run at right angles to each other. This reduces the effects of feedthrough on the board. A microstrip

Page 29

Data Sheet AD5724/AD5734/AD5754

technique is by far the best method, but it is not always possible with a double-sided board. In this technique, the component side of the board is dedicated to a ground plane and signal traces are placed on the solder side.

GALVANICALLY ISOLATED INTERFACE

In many process control applications, it is necessary to provide an isolation barrier between the controller and the unit being controlled to protect and isolate the controlling circuitry from any hazardous common-mode voltages that may occur. The iCoupler® family of products from Analog Devices, Inc., provides voltage isolation in excess of 2.5 kV. The serial loading structure of the AD5724/AD5734/AD5754 makes them ideal for isolated interfaces because the number of interface lines is kept to a minimum. Figure 45 shows a 4-channel isolated interface to the

AD5724/AD5734/AD5754 using an ADuM1400. For further

information, visit http://www.analog.com/icouplers.

MICROCONTROLLER

SERIAL CLOCK OUT

SERIAL DATA OUT

SYNC OUT

CONTROL OUT

*ADDITIONAL PINS OMITTED FOR CLARITY.

Figure 45. Isolated Interface

DuM1400*

ENCODE DECODE

TO SCLK

TO SDIN

TO SYNC

TO LDAC

VOLTAGE REFERENCE SELECTION

To achieve optimum performance from the AD5724/AD5734/

AD5754 over the full operating temperature range of the devices, a

precision voltage reference must be used. Thought must be given to the selection of a precision voltage reference. The voltage applied to the reference inputs are used to provide a buffered positive and negative 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. Choosing a reference with an output trim adjustment, such as the ADR421, allows a system designer to trim out system errors by setting the reference voltage to a voltage other than the nominal. The trim adjustment can also trim out temperature-induced errors.

06468-011

The temperature coefficient of a reference output voltage



affects INL, DNL, and TUE. A reference with a tight temperature coefficient specification must be chosen to reduce the dependence of the DAC output voltage on ambient conditions.

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 the entire lifetime.

Consider reference output voltage noise in high accuracy



applications that have relatively low noise budgets. It is important to choose a reference with as low an output noise voltage as practical for the required system resolution. Precision voltage references such as the ADR431 (XFET® design) produce low output noise in the 0.1 Hz to 10 Hz range. However, as the circuit bandwidth increases, filtering the output of the reference may be required to minimize the output noise.

MICROPROCESSOR INTERFACING

Microprocessor interfacing to the AD5724/AD5734/AD5754 is via a serial bus that uses standard protocol compatible with microcontrollers and DSP processors. The communications channel is a 3-wire (minimum) interface consisting of a clock signal, a data signal, and a synchronization signal. The AD5724/AD5734/

AD5754 require a 24-bit data-word with data valid on the

falling edge of SCLK.

For all interfaces, the DAC output update can be initiated automatically when all the data is clocked in, or it can be

LDAC

performed under the control of registers can be read using the readback function.

AD5724/AD5734/AD5754 to Blackfin® DSP Interface

Figure 46 shows how the AD5724/AD5734/AD5754 can be interfaced to the Analog Devices Blackfin DSP. The Blackfin has an integrated SPI port that can be connected directly to the SPI pins of the AD5724/AD5734/AD5754 and the programmable I/O pins that can be used to set the state of a digital input such as the LDAC

pin.

SPISELx

SCK

MOSI

ADSP-BF531

PF10

. The contents of the

SYNC SCLK

SDIN

AD5724/ AD5734/

AD5754

LDAC

06468-012

Figure 46. AD5724/AD5734/AD5754 to Blackfin Interface

Rev. F | Page 29 of 31

Page 30

AD5724/AD5734/AD5754 Data Sheet

Table 28. Some Precision References Recommended for Use with the AD5724/AD5734/AD5754

Part No. Initial Accuracy (mV Max) Long-Term Drift (ppm Typ) Temp Drift (ppm/°C Max) 0.1 Hz to 10 Hz Noise (µV p-p Typ)

ADR431 ±1 40 3 3.5 ADR421 ±1 50 3 1.75 ADR03 ±2.5 50 3 6 ADR291 ±2 50 8 8 AD780 ±1 20 3 4

Rev. F | Page 30 of 31

Page 31

Data Sheet AD5724/AD5734/AD5754

COMPLIANT

TO JEDEC ST

ANDARDS MO-153-ADT

061708-A

121

6.40 BSC

0.15

0.05

0.10 COPLANARI T

VIEW

EXPOSED

(Pins Up)

BOT

OM VIEW

4.50

4.40

4.30

7.90

7.80

7.70

1.20 MAX

1.05

1.00

0.80

0.65

BSC

0.30

0.19

SEATING PLANE

0.20

0.09

8° 0°

0.75

0.60

0.45

5.02

5.00

4.95

3.25

3.20

3.15

FOR PROPE R CONNECTIO N OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTIO N DES CRIPTIO NS SECTION OF THIS DATA SHEET.

AD5754AREZ

−40°C to +85°C

0.3% FSR

±16 LSB

24-Lead TSSOP_EP

RE-24

OUTLINE DIMENSIONS

Figure 47. 24-Lead Thin Shrink Small Outline Package, Exposed Pad [TSSOP_EP]

(RE-24)

Dimensions shown in millimeters

ORDERING GUIDE

Model1 Resolution (Bits) Temperature Range TUE INL Package Description Package Option

AD5724AREZ 12 −40°C to +85°C 0.3% FSR ±1 LSB 24-Lead TSSOP_EP RE-24 AD5724AREZ-REEL7 12 −40°C to +85°C 0.3% FSR ±1 LSB 24-Lead TSSOP_EP RE-24 AD5734AREZ 14 −40°C to +85°C 0.3% FSR ±4 LSB 24-Lead TSSOP_EP RE-24 AD5734AREZ-REEL7 14 −40°C to +85°C 0.3% FSR ±4 LSB 24-Lead TSSOP_EP RE-24

AD5754AREZ-REEL7 16 −40°C to +85°C 0.3% FSR ±16 LSB 24-Lead TSSOP_EP RE-24 AD5754BREZ 16 −40°C to +85°C 0.1% FSR ±16 LSB 24-Lead TSSOP_EP RE-24 AD5754BREZ-REEL7 16 −40°C to +85°C 0.1% FSR ±16 LSB 24-Lead TSSOP_EP RE-24

Z = RoHS Compliant Part.

registered trademarks are the property of their respective owners. D06468-0-2/17(F)

Rev. F | Page 31 of 31

Analog AD5724, AD5734, AD5754 Data Sheet

FEATURES

APPLICATIONS

GENERAL DESCRIPTION

FUNCTIONAL BLOCK DIAGRAM

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

AC PERFORMANCE CHARACTERISTICS

TIMING CHARACTERISTICS

TIMING DIAGRAMS

ABSOLUTE MAXIMUM RATINGS

ESD CAUTION

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

TYPICAL PERFORMANCE CHARACTERISTICS

TERMINOLOGY

THEORY OF OPERATION

ARCHITECTURE

Output Amplifiers

Reference Buffers

POWER-UP SEQUENCE

SERIAL INTERFACE

Input Shift Register

Standalone Operation

Daisy-Chain Operation

Readback Operation

Individual DAC Updating

Simultaneous Updating of All DACs

CONFIGURING THE AD5724/AD5734/AD5754

TRANSFER FUNCTION

Ideal Output Voltage to Input Code Relationship—AD5754

Ideal Output Voltage to Input Code Relationship—AD5734

Ideal Output Voltage to Input Code Relationship—AD5724

INPUT SHIFT REGISTER

DAC REGISTER

OUTPUT RANGE SELECT REGISTER

CONTROL REGISTER

POWER CONTROL REGISTER

FEATURES

ANALOG OUTPUT CONTROL

POWER-DOWN MODE

OVERCURRENT PROTECTION

Constant Current Clamp (Clamp Enable = 1)

Automatic Channel Power-Down (Clamp Enable = 0)

THERMAL SHUTDOWN

APPLICATIONS INFORMATION

+5 V/±5 V OPERATION

ALTERNATIVE POWER-UP SEQUENCE SUPPORT

LAYOUT GUIDELINES

GALVANICALLY ISOLATED INTERFACE

VOLTAGE REFERENCE SELECTION

MICROPROCESSOR INTERFACING

AD5724/AD5734/AD5754 to Blackfin® DSP Interface

OUTLINE DIMENSIONS

ORDERING GUIDE