Datasheet DAC7744EC-1K, DAC7744EC, DAC7744EB-1K, DAC7744EB, DAC7744E-1K Datasheet (Burr Brown Corporation)

1

®

DAC7744

16-Bit, Quad Voltage Output

DIGITAL-TO-ANALOG CONVERTER

®

DAC7744

DESCRIPTION

The DAC7744 is a 16-bit, quad voltage output digitalto-analog converter with guaranteed 16-bit monotonic performance over the specified temperature range. It accepts 16-bit parallel input data, has double-buffered DAC input logic (allowing simultaneous update of all DACs), and provides a readback mode of the internal input registers. Programmable asynchronous reset clears all registers to a mid-scale code of 8000H or to a zero-scale of 0000H. The DAC7744 operates from either a single +15V supply or from a +15V, –15V, and +5V supply.

Low power and small size per DAC make the DAC7744 ideal for automatic test equipment, DAC-per-pin programmers, data acquisition systems, and closed-loop servo-control. The DAC7744 is available in a 48lead SSOP package, and offers guaranteed specifications over the –40°C to +85°C temperature range.

FEATURES

● LOW POWER: 200mW

● UNIPOLAR OR BIPOLAR OPERATION

● SINGLE-SUPPLY OUTPUT RANGE: +10V

● DUAL SUPPLY OUTPUT RANGE: ±10V

● SETTLING TIME: 10µs to 0.003%

● 16-BIT MONOTONICITY: –40°C to +85°C

● PROGRAMMABLE RESET TO MID-SCALE

OR ZERO-SCALE

● DATA READBACK

● DOUBLE-BUFFERED DATA INPUTS

APPLICATIONS

● PROCESS CONTROL

● ATE PIN ELECTRONICS

● CLOSED-LOOP SERVO-CONTROL

● MOTOR CONTROL

● DATA ACQUISITION SYSTEMS

● DAC-PER-PIN PROGRAMMERS

DAC7744

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111

Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132

For most current data sheet and other product

information, visit www.burr-brown.com

DAC A

DAC

Register A

Input

Register A

DAC7744

I/O

Buffer

Control

Logic

DAC B

DAC

Register B

Input

Register B

DAC C

DAC

Register C

Input

Register C

DAC D

DAC

Register D

Input

Register D

V

REF

L AB V

REF

H AB

V

REF

H

AB Sense

V

REF

L

AB Sense

V

OUT

D

V

OUT

C

V

OUT

B

V

OUT

A

V

OUTB

Sense

V

REF

L CD V

REF

H CD

RST LOADDACs

A1 A0

CS

R/W

DATA I/O

16

RSTSEL

AGND DGND

V

OUTC

Sense

V

OUTD

Sense

V

OUTA

Sense

V

CC

V

SS

V

DD

V

REF

L

CD Sense

V

REF

H

CD Sense

2

®

DAC7744

DAC7744E DAC7744EB DAC7744EC PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS ACCURACY

Linearity Error T = 25°C ±3 ✻ ±2 LSB

T

MIN

to T

MAX

±4 ✻ ±3 LSB Linearity Match ±4 ✻ ±2 LSB Differential Linearity Error T = 25°C ±3 ±2 ±1 LSB

T

MIN

to T

MAX

±3 ±2 ±1 LSB Monotonicity, T

MIN

to T

MAX

14 15 16 Bits

Bipolar Zero Error

T = 25°C ±0.01 ±0.025 ✻✻% of FSR

Bipolar Zero Error, T

MIN

to T

MAX

±0.05 ✻✻% of FSR Full-Scale Error T = 25°C ±0.025 ✻✻% of FSR Full-Scale Error, T

MIN

to T

MAX

±0.05 ✻✻% of FSR Bipolar Zero Matching Channel-to-Channel ±0.024 ✻✻% of FSR

Matching

Full-Scale Matching Channel-to-Channel ±0.024 ✻✻% of FSR

Matching

Power Supply Rejection Ratio (PSRR)

At Full Scale 25 ✻✻ppm/V

ANALOG OUTPUT

Voltage Output V

REF

LV

REF

H ✻✻✻✻V Output Current ±5 ✻✻ mA Maximum Load Capacitance 500 ✻✻pF Short-Circuit Current ±20 ✻✻mA Short-Circuit Duration To V

SS

, V

DD

or GND Indefinite ✻✻

REFERENCE INPUT

Ref High Input Voltage Range

V

REF

L + 1.25

+10 ✻✻✻✻V

Ref Low Input Voltage Range –10

V

REF

H – 1.25

✻✻✻✻V Ref High Input Current –0.3 2.6 ✻✻mA Ref Low Input Current –3.2 –0.3 ✻✻mA

DYNAMIC PERFORMANCE

Settling Time To ±0.003%, 20V 9 11 ✻✻ ✻✻ µs

Output Step Channel-to-Channel Crosstalk See Figure 5 0.5 ✻✻LSB Digital Feedthrough 2 ✻✻nV-s Output Noise Voltage f = 10kHz 60 ✻✻nV/√Hz

DIGITAL INPUT

V

IH

0.7 • V

DD

V

DD

✻✻ V

V

IL

0 0.3 • V

DD

✻ V

I

IH

±10 ✻ µA

I

IL

±10 ✻ µA

DIGITAL OUTPUT

V

OH

IOH = –0.8mA 3.6 4.5 ✻✻ ✻✻ V

V

OL

IOL = 1.6mA 0.3 0.4 ✻✻ ✻✻ V

POWER SUPPLY

V

DD

+4.75 +5.0 +5.25 ✻✻✻✻✻ ✻ V

V

CC

+14.25 +15.0 +15.75 ✻✻✻✻✻✻ V

V

SS

–14.25 –15.0 –15.75 ✻✻✻✻✻✻ V

I

DD

50 ✻✻µA

I

CC

6 ✻✻mA

I

SS

–5 ✻✻mA

Power 170 200 ✻✻mW

TEMPERATURE RANGE

Specified Performance –40 +85 ✻✻✻✻°C

✻ Specifications same as grade to the left.

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.

SPECIFICATIONS (Dual Supply)

At TA = T

MIN

to T

MAX

, VCC = +15V, VDD = +5V, VSS = –15V, V

REF

H = +10V, and V

REF

L = –10V, unless otherwise noted.

3

®

DAC7744

DAC7744E DAC7744EB DAC7744EC PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS ACCURACY

Linearity Error

(1)

T = 25°C ±3 ✻ ±2 LSB

T

MIN

to T

MAX

±4 ✻ ±3 LSB Linearity Match ±4 ✻ ±2 LSB Differential Linearity Error T = 25°C ±3 ±2 ±1 LSB

T

MIN

to T

MAX

±3 ±2 ±1 LSB Monotonicity, T

MIN

to T

MAX

14 15 16 Bits Unipolar Zero T = 25°C ±0.01 ±0.025 ✻✻% of FSR Unipolar Zero Error,

T

MIN

to T

MAX

±0.05 ✻✻% of FSR Full-Scale Error T = 25°C ±0.025 ✻✻% of FSR Full-Scale Error,

T

MIN

to T

MAX

±0.05 ✻✻% of FSR Unipolar Zero Matching Channel-to-Channel ±0.024 ✻✻% of FSR

Matching

Full-Scale Matching Channel-to-Channel ±0.024 ✻✻% of FSR

Matching

Power Supply Rejection Ratio (PSRR)

At Full Scale 25 ✻✻ppm/V

ANALOG OUTPUT

Voltage Output V

REF

L = 0V, VSS = 0V 0 V

REF

H ✻✻✻✻V

R = 10kΩ Output Current ±5 ✻✻ mA Maximum Load Capacitance 500 ✻✻pF Short-Circuit Current ±20 ✻✻mA Short-Circuit Duration To V

SS

, V

CC

or GND Indefinite ✻✻

REFERENCE INPUT

Ref High Input Voltage Range

V

REF

L + 1.25

+10 ✻✻✻✻V

Ref Low Input Voltage Range 0

V

REF

H – 1.25

✻✻✻✻V Ref High Input Current –0.3 1.0 ✻✻mA Ref Low Input Current –1.5 –0.3 ✻✻mA

DYNAMIC PERFORMANCE

Settling Time To ±0.003%, 10V 8 10 ✻✻ ✻✻ µs

Output Step Channel-to-Channel Crosstalk See Figure 6 0.5 ✻✻LSB Digital Feedthrough 2 ✻✻nV-s Output Noise Voltage f = 10kHz 60 ✻✻nV/√Hz

DIGITAL INPUT

V

IH

0.7 • V

DD

V

DD

✻✻ V

V

IL

0 0.3 • V

DD

✻ V

I

IH

±10 ✻ µA

I

IL

±10 ✻ µA

DIGITAL OUTPUT

V

OH

IOH = –0.8mA 3.6 4.5 ✻✻ ✻✻ V

V

OL

IOL = 1.6mA 0.3 0.4 ✻✻ ✻✻ V

POWER SUPPLY

V

DD

+4.75 +5.0 +5.25 ✻✻✻✻✻✻ V

V

CC

+14.25 +15.0 +15.75 ✻✻✻✻✻✻ V

V

SS

0 ✻✻V

I

DD

50 ✻✻µA

I

CC

3.5 ✻✻mA

Power 50 70 ✻✻mW

TEMPERATURE RANGE

Specified Performance –40 +85 ✻✻✻✻°C

✻ Specifications same as grade to the left.

NOTE: (1) If V

SS

= 0V, the specification applies at code 0021H and above, due to possible negative zero scale error.

SPECIFICATIONS (Single Supply)

At TA = T

MIN

to T

MAX

, VCC = +15V, VDD = +5V, VSS = GND, V

REF

H = +10V, and V

REF

L = +50mV, unless otherwise noted.

4

®

DAC7744

ABSOLUTE MAXIMUM RATINGS

(1)

V

CC

to VSS...........................................................................–0.3V to +32V

V

CC

to AGND ...................................................................... –0.3V to +16V

V

SS

to AGND ...................................................................... +0.3V to –16V

AGND

to DGND................................................................. –0.3V to +0.3V

V

REFH

to AGND ..................................................................... –9V to +11V

V

REFL

to AGND...................................................................... –11V to +9V

V

DD

to GND ........................................................................... –0.3V to +6V

V

REFH

to V

REF

L ........................................................................ –1V to 22V

Digital Input Voltage to GND ................................... –0.3V to V

DD

+ 0.3V

Digital Output Voltage to GND................................. –0.3V to V

DD

+ 0.3V

Maximum Junction Temperature................................................... +150 °C

Operating Temperature Range ........................................–40°C to +85°C

Storage Temperature Range .........................................–65°C to +150°C

Lead Temperature (soldering, 10s)............................................... +300°C

NOTE: (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.

ELECTROSTATIC DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Burr-Brown 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.

PACKAGE/ORDERING INFORMATION

LINEARITY DIFFERENTIAL PACKAGE SPECIFICATION

ERROR NONLINEARITY DRAWING TEMPERATURE ORDERING TRANSPORT

PRODUCT (LSB) (LSB) PACKAGE NUMBER RANGE NUMBER

(1)

MEDIA

DAC7744E ±4 ±3 48-Lead SSOP 333 –40°C to +85°C DAC7744E Rails

"" """ "DAC7744E/1K Tape and Reel

DAC7744EB ±4 ±2 48-Lead SSOP 333 –40°C to +85°C DAC7744EB Rails

"" """ "DAC7744EB/1K Tape and Reel

DAC7744EC ±3 ±1 48-Lead SSOP 333 –40°C to +85°C DAC7744EC Rails

"" """ "DAC7744EC/1K Tape and Reel

NOTE: (1) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /1K indicates 1000 devices per reel). Ordering 1000 pieces of “DAC7744E/1K” will get a single 1000-piece Tape and Reel.

RefH

V

OUT

Sense

V

CC

V

SS

V

DD

DGND

4

V

CC

AGND

V

SS

V

DD

DGND

V

OUT

RefH Sense

RefL Sense

RefL

1 of 2

1 of 4

Typ of Each

Logic Input Pin

Typ of Each

I/O Pin

ESD PROTECTION CIRCUITS

5

®

DAC7744

PIN DESCRIPTIONS

PIN NAME DESCRIPTION

1 DB15 Data Bit 15, MSB 2 DB14 Data Bit 14 3 DB13 Data Bit 13 4 DB12 Data Bit 12 5 DB11 Data Bit 11 6 DB10 Data Bit 10 7 DB9 Data Bit 9 8 DB8 Data Bit 8

9 DB7 Data Bit 7 10 DB6 Data Bit 6 11 DB5 Data Bit 5 12 DB4 Data Bit 4 13 DB3 Data Bit 3 14 DB2 Data Bit 2 15 DB1 Data Bit 1 16 DB0 Data Bit 0, LSB 17 RSTSEL Reset Select. Determines the action of RST. If

HIGH, a RST command will set the DAC registers to mid-scale. If LOW, a RST command will set the DAC registers to zero.

18 RST Reset, Edge-Triggered. Depending on the state

of RSTSEL, the DAC Input and Output registers are set to either mid-scale or zero.

19 LOADDACs DAC Output Registers Load Control. Rising edge

triggered.

20 R/W Enabled by the CS, controls data read and write

from the input register.

21 A1 Enabled by the CS, in combination with A0

selects the Individual DAC Input Registers.

22 A0 Enabled by the CS, in combination with A1

selects the individual DAC input registers. 23 CS Chip Select, Active LOW. 24 DGND Digital Ground

25 V

DD

Positive Power Supply 26 V

CC

Positive Power Supply 27 AGND Analog Ground 28 V

SS

Negative Power Supply 29 V

OUT

D DAC D Voltage Output

30 V

OUT

D Sense DAC D’s Output Amplifier Inverting Input. Used

to close the feedback loop at the load. 31 V

REF

L CD Sense DAC C and D Reference Low Sense Input

32 V

REF

L CD DAC C and D Reference Low Input

33 V

REF

H CD DAC C and D Reference High Input

34 V

REF

H CD Sense DAC C and D Reference High Sense Input

35 V

OUT

C DAC C Voltage Output

36 V

OUT

C Sense DAC C’s Output Amplifier Inverting Input. Used

to close the feedback loop at the load. 37 V

OUT

B DAC B Voltage Output

38 V

OUT

B Sense DAC B’s Output Amplifier Inverting Input. Used

to close the feedback loop at the load. 39 V

REF

H AB Sense DAC A and B Reference High Sense Input

40 V

REF

H AB DAC A and B Reference High Input

41 V

REF

L AB DAC A and B Reference Low Input

42 V

REF

L AB Sense DAC A and B Reference Low Sense Input

43 V

OUT

A DAC A Voltage Input

44 V

OUT

A Sense DAC A’s Output Amplifier Inverting Input. Used

to close the feedback loop at the load. 45 NC No Connection 46 NC No Connection 47 NC No Connection 48 NC No Connection

Top View SSOP

PIN CONFIGURATION

DB15 (MSB)

DB14 DB13 DB12 DB11 DB10

DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1

DB0 (LSB)

RSTSEL

RST

LOADDACs

R/W

A1 A0

CS

DGND

NC NC NC NC V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

V

OUT

C Sense

V

OUT

C

V

REF

H CD Sense

V

REF

H CD

V

REF

L CD

V

REF

L CD Sense

V

OUT

D Sense

V

OUT

D

V

SS

AGND V

CC

V

DD

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25

DAC7744

6

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = 0V

At TA = +25°C, VDD = +5V, VCC = +15V, V

SS

= 0, V

REFH

= +10V, and V

REFL

= 0V, representative unit, unless otherwise specified.

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5

0 –0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

+25°C

+85°C

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

7

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, V

SS

= 0, V

REFH

= +10V, and V

REFL

= 0V, representative unit, unless otherwise specified.

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000HC000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

+85°C (cont.)

–40°C

8

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, V

SS

= 0, V

REFH

= +10V, and V

REFL

= 0V, representative unit, unless otherwise specified.

2

1.5 1

0.5 0

–0.5

–1

–1.5

–2

Temperature (°C)

–40 –30 –10 0–20 10 20 40 5030 70 80 9060

ZERO-SCALE ERROR vs TEMPERATURE

Zero-Scale Error (mV)

DAC A

DAC D

DAC B

DAC C

Code (0040H)Code (0021H)

2

1.5 1

0.5 0

–0.5

–1

–1.5

–2

Temperature (°C)

–40 –30 –10 0–20 10 20 40 5030 70 80 9060

FULL-SCALE ERROR vs TEMPERATURE

Positive Full-Scale Error (mV)

DAC A

DAC D

DAC B

DAC C

Code (FFFFH)

1.0

0.8

0.6

0.4

0.2 0

–0.2 –0.4

0

–0.2 –0.4 –0.6 –0.8 –1.0 –1.2 –1.4

V

REF

Current (mA)V

REF

Current (mA)

CURRENT vs CODE

All DACS Sent to Indicated Code

(DAC C and D)

V

REFH

V

REFL

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5 0

Digital Input Code

0 2000H4000H6000H8000HA000HC000HE000HFFFF

H

POSITIVE SUPPLY CURRENT

vs DIGITAL INPUT CODE

I

CC

(mA)

No Load

1.0

0.8

0.6

0.4

0.2 0

–0.2 –0.4

0

–0.2 –0.4 –0.6 –0.8 –1.0 –1.2 –1.4

V

REF

Current (mA)V

REF

Current (mA)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

CURRENT vs CODE

All DACs Sent to Indicated Code

(DAC A and B)

V

REFH

V

REFL

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5 0

–0.5

Temperature (°C)

–40 –30 –10 0–20 10 20 40 5030 70 80 9060

POWER SUPPLY CURRENT vs TEMPERATURE

Quiescent Current (mA)

I

CC

I

DD

Data = FFFFH (all DACs)

No Load

9

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, V

SS

= 0, V

REFH

= +10V, and V

REFL

= 0V, representative unit, unless otherwise specified.

BROADBAND NOISE

Time (100µs/div)

Noise Voltage (20µV/div)

BW = 10kHz

Code = 8000

H

+5V LDAC 0

Time (2µs/div)

OUTPUT VOLTAGE vs SETTLING TIME

(0V to +10V)

Output Voltage

Small-Signal Settling Time: 3LSB/div

Large-Signal Settling Time: 5V/div

+5V LDAC 0

Time (2µs/div)

OUTPUT VOLTAGE vs SETTLING TIME

(+10V to 0V)

Output Voltage

Small-Signal Settling Time: 3LSB/div

Large-Signal Settling Time: 5V/div

120

100

80

60

40

20

0

Frequency (Hz)

100

1k

10k 100k

1M

OUTPUT NOISE VOLTAGE vs FREQUENCY

Noise (nV/√Hz)

+5V LDAC 0

Time (1µs/div)

OUTPUT VOLTAGE

MIDSCALE GLITCH PERFORMANCE

Output Voltage (50mV/div)

7FFFH to 8000

H

+5V LDAC 0

Time (1µs/div)

Output Voltage (50mV/div)

8000H to 7FFF

H

OUTPUT VOLTAGE

MIDSCALE GLITCH PERFORMANCE

10

®

DAC7744

0 –10 –20 –30 –40 –50 –60 –70 –80 –90

Frequency (Hz)

100

1k

10k 100k 1M

POWER SUPPLY REJECTION RATIO vs FREQUENCY

PSRR (dB)

+15V

+5V

TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, V

SS

= 0, V

REFH

= +10V, and V

REFL

= 0V, representative unit, unless otherwise specified.

20 15 10

5 0

–5 –10 –15 –20

Input Code

0000H2000H4000H6000H8000HA000H0000HE000HFFFF

H

SINGLE-SUPPLY CURRENT LIMIT

vs INPUT CODE

I

OUT

(mA)

Short to Ground

Short to V

CC

16 14 12 10

8 6 4 2 0

R

LOAD

(kΩ)

0.01

0.1

1 10 100

OUTPUT VOLTAGE vs R

LOAD

V

OUT

(V)

Source

Sink

12

10

8

6

4

2

0

LOGIC SUPPLY CURRENT

vs LOGIC INPUT LEVEL FOR DATA BITS

Logic Supply Current (mA)

Logic Input Level for Data Bits (V)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

+5V

CS 0

Time (500ns/div)

DIGITAL-TO-ANALOG OUTPUT GLITCH

Output Voltage (50mV/div)

2LSB/div

11

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = –15V

At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, V

REFH

= +10V, and V

REFL

= –10V, representative unit, unless otherwise specified.

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

+25°C

+85°C

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

12

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, V

REFH

= +10V, and V

REFL

= –10V, representative unit, unless otherwise specified.

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

+85°C (cont.)

–40°C

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, –40°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +85°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

13

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, V

REFH

= +10V, and V

REFL

= –10V, representative unit, unless otherwise specified.

2.0

1.5

1.0

0.5 0

-0.5 –1.0 –1.5

0.5 0

–0.5 –1.0 –1.5 –2.0 –2.5 –3.0

V

REF

Current (mA)V

REF

Current (mA)

CURRENT vs CODE

All DACs Sent to Indicated Code

(DAC A and B)

V

REFH

V

REFL

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5

0.5 0

–0.5 –1.0 –1.5 –2.0 –2.5 –3.0

V

REF

Current (mA)V

REF

Current (mA)

CURRENT vs CODE

All DACs Sent to Indicated Code

(DAC C and D)

V

REFH

V

REFL

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2

1.5 1

0.5 0

–0.5

–1

–1.5

–2

Temperature (°C)

–40 –20 100020406080

BIPOLAR ZERO SCALE ERROR vs TEMPERATURE

(Code 8000

H

)

Bipolar Zero Scale Error (mV)

DAC B

DAC D

DAC A

DAC C

2

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

Temperature (°C)

–40 –10 0–30 –20 9010 20 30 40 50 60 70 80

POSITIVE FULL-SCALE ERROR vs TEMPERATURE

(Code FFFF

H

)

Positive Full-Scale Error (mV)

DAC B

DAC A

DAC C

DAC D

2

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

Temperature (°C)

–40 –10 0–30 –20 9010 20 30 40 50 60 70 80

NEGATIVE FULL-SCALE ERROR vs TEMPERATURE

(Code 0000

H

)

Negative Full-Scale Error (mV)

DAC B

DAC A

DAC C

DAC D

7 6 5 4 3 2 1

0 –1 –2 –3 –4 –5 –6 –7

Temperature (°C)

–40 –10 0–30 –20 9010 20 30 40 50 60 70 80

POWER SUPPLY CURRENT vs TEMPERTURE

Quiescent Current (mA)

I

SS

I

CC

I

DD

Data = FFFF

H

(all DACs)

No Load

14

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, V

REFH

= +10V, and V

REFL

= –10V, representative unit, unless otherwise specified.

0 –10 –20 –30 –40 –50 –60 –70 –80 –90

–100

Frequency (Hz)

100

1k

10k 100k 1M

POWER SUPPLY REJECTION RATIO vs FREQUENCY

PSRR (dB)

–15V

+15V

+5V

15

10

5

0

–5

–10

–15

R

LOAD

(kΩ)

0.01

0.1

1 10 100

OUTPUT VOLTAGE vs R

LOAD

V

OUT

(V)

Sink

Source

Time (2µs/div)

OUTPUT VOLTAGE vs SETTLING TIME

(+10V to –10V)

Output Voltage

Large-Signal Settling Time: 5V/div

Small-Signal Settling Time: 3LSB/div

+5V LDAC 0

Time (2µs/div)

OUTPUT VOLTAGE vs SETTLING TIME

(–10V to +10V)

Output Voltage

Large-Signal Settling Time: 5V/div

Small-Signal Settling Time: 3LSB/div

+5V LDAC 0

20 15 10

5 0

–5 –10 –15 –20

DUAL SUPPLY CURRENT LIMIT vs INPUT CODE

Short to Ground

I

OUT

(mA)

Digital Input Code

0000H2000H4000H6000H8000HA000HC000HE000HFFFF

H

7 6 5 4 3 2 1 0 1 2 3 4 5 6 7

SUPPLY CURRENT vs CODE

(mA)

Digital Input Code

0000H2000H4000H6000H8000HA000HC000HE000HFFFF

H

I

CC

I

DD

I

SS

15

®

DAC7744

TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.)

At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, V

REFH

= +10V, and V

REFL

= –10V, representative unit, unless otherwise specified.

Time (1µs/div)

OUTPUT VOLTAGE

MID-SCALE GLITCH PERFORMANCE

Output Voltage (50mV/div)

7FFFH to 8000

H

+5V LDAC 0

Time (1µs/div)

OUTPUT VOLTAGE

MID-SCALE GLITCH PERFORMANCE

Output Voltage (50mV/div)

8000H to 7FFF

H

+5V LDAC 0

16

®

DAC7744

FIGURE 1. DAC7744 Architecture.

FIGURE 2. Basic Single-Supply Operation of the DAC7744.

THEORY OF OPERATION

The DAC7744 is a quad voltage output, 16-bit digital-toanalog converter (DAC). The architecture is an R-2R ladder configuration with the three MSB’s segmented followed by an operational amplifier that serves as a buffer. Each DAC has its own R-2R ladder network, segmented MSBs and output op amp (see Figure 1). The minimum voltage output (zero scale) and maximum voltage output (full scale) are set

by the external voltage references (V

REF

L and V

REF

H, respectively). The digital input is a 16-bit parallel word and the DAC input registers offer a readback capability. The converters can be powered from either a single +15V supply or a dual ±15V supply. The device offers a reset function which immediately sets all DAC output voltages and DAC registers to mid-scale code 8000H or to zero scale, code 0000H. See Figures 2 and 3 for the basic operation of the DAC7744.

R

2R

2R2R 2R 2R 2R 2R 2R 2R

V

REF

H

V

OUT

V

OUT

Sense

V

REF

H Sense

V

REF

L

V

REF

L Sense

R

F

DB15 (MSB) DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 (LSB) RSTSEL RST LOADDACS R/W A1 A0 CS DGND

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

V

OUT

C Sense

V

OUT

C

V

REF

H CD Sense

V

REF

H CD

V

REF

L CD

V

REF

L CD Sense

V

OUT

D Sense

V

OUT

D

V

SS

AGND

V

CC

V

DD

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25

DAC7744

Reset DACs

Data

Bus

Address

Load DAC Registers

READ/WRITE

Chip Select

NC = No Connection

0V to +10V

+10.000V

+15V

0.1µF

1µF

+5V

0.1µF

1µF

+

17

®

DAC7744

ANALOG OUTPUTS

When VSS = –15V (dual supply operation), the output amplifier can swing to within 4V of the supply rails, guaranteed over the –40°C to +85°C temperature range. With VSS = 0V (single-supply operation), and with R

LOAD

also connected to ground, the output can swing to ground. Care must also be taken when measuring the zero-scale error when VSS = 0V. Since the output voltage cannot swing below ground, the output voltage may not change for the first few digital input codes (0000H, 0001H, 0002H, etc.), if the output amplifier has a negative offset. At the negative limit of –5mV, the first specified output starts at code 0021H.

Due to the high accuracy of these D/A converters, system design problems such as grounding and contact resistance become very important. A 16-bit converter with a 10V fullscale range has a 1LSB value of 152µV. With a load current of 1mA, series wiring and connector resistance of only 150mΩ (RW2) will cause a voltage drop of 150µV, as shown in Figure 4. To understand what this means in terms of a system layout, the resistivity of a typical 1 ounce copper-clad printed circuit board is 1/2 mΩ per square. For a 1mA load, a 20 milli-inch wide printed circuit conductor 6 inches long will result in a voltage drop of 150µV.

The DAC7744 offers a force and sense output configuration for the high open-loop gain output amplifiers. This feature

allows the loop around the output amplifier to be closed at the load, thus ensuring an accurate output voltage, as shown in Figure 4.

FIGURE 3. Basic Dual-Supply Operation of the DAC7744.

FIGURE 4. Analog Output Closed-Loop Configuration

(1/2 DAC7744). RW represents wiring resistances.

DB15 (MSB) DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 (LSB) RSTSEL RST LOADDACS R/W A1 A0 CS DGND

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

V

OUT

C Sense

V

OUT

C

V

REF

H CD Sense

V

REF

H CD

V

REF

L CD

V

REF

L CD Sense

V

OUT

D Sense

V

OUT

D

V

SS

AGND

V

CC

V

DD

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25

DAC7744

Reset DACs

Data

Bus

Address

Load DAC Registers

READ/WRITE

Chip Select

NC = No Connection

–10V to +10V

–10V

–10V to +10V

+10V

+10V –10V

+5V

–15V

0.1µF

1µF

+15V

0.1µF

1µF

+5V

0.1µF

1µF

+

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

R

W1

R

W2

+10V

+V

V

OUT

R

W1

R

W2

V

OUT

R

LOAD

R

LOAD

18

®

DAC7744

REFERENCE INPUTS

The reference inputs, V

REF

L and V

REF

H, can be any voltage

between V

SS

+ 4V and V

CC

– 4V, provided that V

REF

H is at

least 1.25V greater than V

REF

L. The minimum output of

each DAC is equal to V

REFL

plus a small offset voltage (essentially, the offset of the output op amp). The maximum output is equal to V

REF

H plus a similar offset voltage. Note that VSS (the negative power supply) must either be connected to ground or must be in the range of –14.25V to –15.75V. The voltage on VSS sets several bias points within the converter. If VSS is not in one of these two configurations, the bias values may be in error and proper operation of the device is not guaranteed.

The current into the V

REF

H input and out of V

REF

L depends

on the DAC output voltages and can vary from a few

microamps to approximately 2.0mA. The reference input appears as a varying load to the reference. If the reference can sink or source the required current, a reference buffer is not required. The DAC7744 features a reference drive and sense connection such that the internal errors caused by the changing reference current and the circuit impedances can be minimized. Figures 5 through 12 show different reference configurations and the effect on the linearity and differential linearity.

The analog supplies (or the analog supplies and the reference power supplies) have to come up first. If the power supplies for the reference come up first, then the VCC and V

SS

supplies will be “powered from the reference via the ESD protection diode”, see page 4.

FIGURE 5. Dual Supply Configuration-Buffered References, used for Dual Supply Performance Curves (1/2 DAC7744).

FIGURE 6. Single-Supply Buffered Reference with a Reference Low of 50mV Used for Single-Supply Performance Curves

(1/2 DAC7744).

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

+10V

+V

–10V

–V

V

OUT

V

OUT

1000pF

2200pF

+V

OPA2234

100Ω

1000pF

2200pF

100Ω

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

99kΩ

2kΩ

+0.050V

+10V

+V

V

OUT

V

OUT

NOTE: V

REF

L has been chosen to be 50mV to allow for current sinking voltage

drops across the 100Ω resistor and the output stage of the buffer op amp.

1000pF

2200pF

+V

OPA350

OPA227

100Ω

1000pF

2200pF

100Ω

19

®

DAC7744

FIGURE 7. Integral Linearity and Differential Linearity Error Curves for Figure 8.

FIGURE 8. Dual-Supply Buffered Referenced with V

REF

L = –5V and V

REF

H = +5V (1/2 DAC7744).

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

+5V

–V

+V

–5V

V

OUT

V

OUT

1000pF

2200pF

+V

OPA2234

100Ω

1000pF

2200pF

100Ω

–V

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +25°C)

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

20

®

DAC7744

FIGURE 9. Single-Supply Buffered Reference with a Reference Low of 50mV and Reference High of +5V.

FIGURE 10. Integral Linearity and Differential Linearity Error Curves for Figure 9.

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC A, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC B, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC C, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

2.0

1.5

1.0

0.5 0

–0.5 –1.0 –1.5 –2.0

1.0

0.5 0

–0.5 –1.0

LE (LSB)DLE (LSB)

LINEARITY ERROR AND

DIFFERENTIAL LINEARITY ERROR vs CODE

(DAC D, +25°C)

0000H2000H4000H6000H8000

H

Digital Input Code

A000

H

C000HE000HFFFF

H

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

V

OUT

V

OUT

99kΩ

0.05V

1kΩ

+5V

+V

1000pF

2200pF

+V

OPA350

OPA227

100Ω

1000pF

2200pF

100Ω

21

®

DAC7744

DIGITAL INTERFACE

Table I shows the basic control logic for the DAC7744. Note that each DAC register is edge triggered and not level triggered. When the LOADDACS signal is transitioned to HIGH, the digital word currently in the DAC register is latched. The first set of registers (the input registers) are triggered via the A0, A1, R/W, and CS inputs. Only one of these registers is transparent at any given time.

The double-buffered architecture is designed mainly so that each DAC input register can be written to at any time and then all DAC voltages updated simultaneously by the rising edge of LOADDACS. It also allows a DAC input register to be written to at any point then the DAC output voltages can be synchronously changed via a trigger signal connected to LOADDACS.

DIGITAL TIMING

Figure 11 and Table II provide detailed timing for the digital interface of the DAC7744.

DIGITAL INPUT CODING

The DAC7744 input data is in Straight Binary format. The output voltage is given by Equation 1.

where N is the digital input code. This equation does not include the effects of offset (zero scale) or gain (full scale) errors.

INPUT DAC

A1 A0 R/W CS RST RSTSEL

LOADDACS

REGISTER REGISTER MODE DAC

LLLLXXX Write Hold Write Input A

L H L L X X X Write Hold Write Input B H L L L X X X Write Hold Write Input C H H L L X X X Write Hold Write Input D

L L H L X X X Read Hold Read Input A

L H H L X X X Read Hold Read Input B H L H L X X X Read Hold Read Input C H H H L X X X Read Hold Read Input D XXXHXX↑ Hold Write Update All X X X H X X H Hold Hold Hold All XXXX↑ L X Reset to Zero Reset to Zero All XXXX↑ H X Reset to Midscale Reset to Midscale All

TABLE I. DAC7744 Logic Truth Table.

DIGITALLY-PROGRAMMABLE CURRENT SOURCE

The DAC7744 offers a unique set of features that allows a wide range of flexibility in designing applications circuits such as programmable current sources. The DAC7744 offers both a differential reference input as well as an open-loop configuration around the output amplifier. The open-loop configuration around the output amplifier allows transistor to be placed within the loop to implement a digitallyprogrammable, uni-directional current source. The availability of a differential reference also allows programmability for both the full-scale and zero-scale currents. The output current is calculated as:

Figure 12 shows a DAC7744 in a 4-to-20mA current output configuration. The output current can be determined by Equation 3:

At full scale, the output current is 16mA plus the 4mA for the zero current. At zero scale, the output current is the offset current of 4mA (1V/250Ω).

(1)

VVL

VHVLN

OUT REF

REF REF

=+

()

–•

,65 536

(3)

I

VV N V

OUT

=

 

 

 



 



 



 



+

 

 

51

250 65 536

1

250

–

•

,ΩΩ

(2)

I

VHVLRN

VLR

OUT

REF REF

SENSE

REF SENSE

=

 



 



 



 



 



 



+

()

–

• ,/65 536

22

®

DAC7744

SYMBOL DESCRIPTION MIN TYP MAX UNITS

t

RCS

CS LOW for Read 100 ns

t

RDS

R/W HIGH to CS LOW 10 ns

t

RDH

R/W HIGH after CS HIGH 10 ns

t

DZ

CS HIGH to Data Bus in High Impedance 10 70 ns

t

CSD

CS LOW to Data Bus Valid 85 130 ns

t

WCS

CS LOW for Write 40 ns

t

WS

R/W LOW to CS LOW 0 ns

t

WH

R/W LOW after CS HIGH 10 ns

t

AS

Address Valid to CS LOW 0 ns

t

AH

Address Valid after CS HIGH 15 ns

t

LS

CS LOW to LOADDACS HIGH 40 ns

t

LH

CS LOW after LOADDACS HIGH 80 ns

t

LX

LOADDACS HIGH 40 ns

t

DS

Data Valid to CS LOW 0 ns

t

DH

Data Valid after CS HIGH 15 ns

t

LWD

LOADDACS LOW 40 ns

t

SS

RSTSEL Valid Before RESET HIGH 0 ns

t

SH

RSTSEL Valid After RESET HIGH 120 ns

t

RSS

RESET LOW Before RESET HIGH 10 ns

t

RSH

RESET LOW After RESET HIGH 10 ns

t

S

Settling Time 11 µs

TABLE II. Timing Specifications (TA = –40°C to +85°C).

FIGURE 11. Digital Input and Output Timing.

t

RCS

CS

t

RDS

t

RDH

t

AS

t

CSD

t

DZ

t

AH

R/W

A0/A1

Data Out

Data Valid

t

WCS

CS

t

WS

t

AS

t

AH

t

WH

R/W

A0/A1

t

LS

t

LWD

t

LH

t

S

±0.003% of FSR

Error Band

±0.003% of FSR

Error Band

t

LX

LOADDACS

t

DS

t

DH

Data In

V

OUT

Data Read Timing

Data Write Timing

t

RSH

RST

V

OUT

,RESET SEL LOW

+FS

–FS

t

SS

t

SH

RESET SEL

V

OUT

,RESET SEL HIGH

MS

+FS

–FS

DAC7744 Reset Timing

t

RSS

23

®

DAC7744

FIGURE 12. 4-to-20mA Digitally-Controlled Current Source (1/2 DAC7744).

NC NC NC NC

V

OUT

A Sense

V

OUT

A

V

REF

L AB Sense

V

REF

L AB

V

REF

H AB

V

REF

H AB Sense

V

OUT

B Sense

V

OUT

B

48 47 46 45 44 43 42 41 40 39 38 37

DAC7744

I

OUT

V

PROGRAMMED

R

SENSE

250Ω

I

OUT

V

PROGRAMMED

R

SENSE

250Ω

GND

80kΩ

+1.0V

20kΩ

+V

1000pF

2200pF

+V

OPA2350

100Ω

1000pF

2200pF

100Ω

Datasheet DAC7744EC-1K, DAC7744EC, DAC7744EB-1K, DAC7744EB, DAC7744E-1K Datasheet (Burr Brown Corporation)

Specifications and Main Features

Frequently Asked Questions

User Manual