AD781

REV. A

–8–

AD781 TO AD674 INTERFACE

Figure 9 shows a typical data acquisition circuit using the

AD781, a high linearity, low aperture jitter SHA and the AD674

a 12-bit high speed ADC. The time between the AD674 status

line going high and the actual start of conversion allows the

AD781 to settle to 0.01%. As a result, the AD674 status line

can be used to control the AD781; only an inverter is needed to

interface the two devices.

CS

DGND

REF IN

REF OUT

BIP OFFSET

R/C

AGND

NC

GAIN

CONVERT

0.1µF

+12V

IN

GND

0.1µF

–12V

OUT

AD781

100

Ω

100

Ω

OFFSET

28

15

3

4

13

14

10

8

12

5

9

5

8

2

3

4

NC

6

NC

1

7

AD674

–12V

4.7µF

0.1µF

11

+12V

4.7µF

0.1µF

7

D0–11

12-BIT

THREE-STATE

DATA

16

27

STS

STATUS

S/H

7404

OR EQUIV.

CE

+5V

6

1

2

12/8

0.1µF

Figure 9. AD781 to AD674 Interface

20

–140

–100

–120

0

–60

–80

–40

–20

0

3

7

10

13

16

20

23

26

30

33

FREQUENCY BINS – kHz

Figure 10. FFT Plot of AD781 to AD674 Interface,

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

Cerdip (Q) Package

Mini-DIP (N) Package