Data Sheet

ADA4625-1/ADA4625-2

Rev. A | Page 31 of 35

DAC OUTPUT DRIVER

AD5791B

INV

1/2

AD8676B

1/2

AD8676B

7

8

11

14

13

12

6

2

1

20

3

4

5

10

15

18

16

19

CLR

LDAC

SDO

SYNC

SCLK

SDIN

RESET

+15V

+3.3V

–15V

+

ADA4625-1

1/2

AD8676B

1/2

AD8676B

+ –

+ –

+

–

A1

C1

B1

B2

PRECISION

5V DC

SOURCE

SPI INTERFACE

AND DIGITAL

CONTROL

–10V TO +10V

OUTPUT

VOLTAGE

0.1µF

10µF

10µF

10µF

0.1µF

0.1µF

10µF

1kΩ

R1

1.5kΩ

R3

2kΩ

R5

R2

1kΩ

C1

+15V

−15V

+15V

−15V

+15V

−15V

+

–

+

–

A2

1kΩ

R4

9

17

Figure 105. 20-Bit Accurate, ±10 V Voltage Source (Simplified Schematic: All Connections and Decoupling Not Shown)

ADA4625-1 can be used as an output buffer for 20-bit accurate,

±10 V voltage source with the AD5791 and the LTC6655. The

low voltage noise, low drift output drive capability of the

ADA4625-1, as well as dynamic parameters such as fast settling

time and slew rate make the device an ideal DAC output buffer.

It is recommended to provide supplies of ±15 V to obtain the

full potential of the ADA4625-1 in this application due to the

2.0

–2.0

–1.5

–1.0

–0.5

0

0.5

1.0

1.5

0

200000

400000

600000

800000

1000000

1200000

DAC CODES

LTC6655 REFERENCE

ADA4625-1 OUTPUT BUFFER

ON-BOARD SUPPLIES FROM ADP7118 AND ADP7182

3458A DMM, NPLC = 10

STEP SIZE = 1024

Figure 106. AD5791 with LTC6655 and ADA4625-1 as Output Buffer INL

Performance

Figure 106 and Figure 107 show the INL response with the

EVAL-AD5791SDZ and the step response of the ADA4625-1 in

comparison to the AD8675, respectively.

TIME (500ns/DIV)

ADA4625-1

AD8675

EVAL-AD5791SDZ

1V STEP FROM DAC

OUTPUT READ AT VO_BUF

Figure 107. Step Response with ADA4625-1 and AD8675 Output Buffers