AD587

Rev. H | Page 10 of 12

APPLICATIONS INFORMATION

USING THE AD587 WITH CONVERTERS

The AD587 is an ideal reference for a variety of 8-bit, 12-bit,

14-bit, and 16-bit ADCs and DACs. Several examples follow.

10 V Reference with Multiplying CMOS DACs or ADCs

The AD587 is ideal for applications with 10-bit and 12-bit

multiplying CMOS DACs. In the standard hookup, shown in

Figure 18, the AD587 is paired with the AD7545 12-bit multi-

plying DAC and the AD711 high speed BiFET op amp. The

amplifier DAC configuration produces a unipolar 0 V to −10 V

output range. Bipolar output applications and other operating

details can be found in the individual product data sheets.

AD587

GND

AD711

–15V

+15V

OUT1

DGND

DB11 TO DB0

C1

33pF

R2

+15V

AD7545

TRIM

+15V

0.1µF

AGND

0.1µF

0.1µF

0V TO –10V

10kΩ

Figure 18. Low Power 12-Bit CMOS DAC Application

The AD587 can also be used as a precision reference for multi-

ple DACs. Figure 19 shows the AD587, the AD7628 dual DAC,

and the AD712 dual op amp hooked up for single-supply

operation to produce 0 V to −10 V outputs. Because both DACs

are on the same die and share a common reference and output

op amps, the DAC outputs will exhibit similar gain temperature

coefficients (TCs).

AD587

GND

AD712

+15V

OUT A

DGND

+15V

AGND

DAC A

DB0

DB7

OUT B

DAC B

18

RFB B

RFB A

AD7628

0.1µF

DATA

INPUTS

0 TO –10V

0 TO –10V

Figure 19. AD587 as a 10 V Reference for a CMOS Dual DAC

Precision Current Source

The design of the AD587 allows it to be easily configured as a cur-

shown in Figure 20, the user can vary the load current from the

quiescent current (2 mA typically) to approximately 10 mA.

2

6

4

GND

AD587

10V

500Ω

MIN

Figure 20. Precision Current Source

Precision High Current Supply

For higher currents, the AD587 can easily be connected to a

power PNP or power Darlington PNP device. The circuits in

Figure 21 and Figure 22 can deliver up to 4 A to the load. The

0.1 μF capacitor is required only if the load has a significant

capacitive component. If the load is purely resistive, improved

high frequency supply rejection results can be obtained by

removing the capacitor.

AD587

2

6

4

2N6285

10V

0.1µF

220Ω

GND

Figure 21. Precision High Current Source

AD587

2

6

4

2N6285

0.1µF

220Ω

+10V @ 4A

GND

Figure 22. Precision High Current Voltage Source