REV. C

AD8001

–13–

0.1 F

20

50

1k

18

17

16

15

14

13

12

11

10pF

CLOCK

5, 9, 22,

24, 37, 41

4,19, 21

25, 27, 42

0.1 F

38

8

6

2

3

649

324

ANALOG

IN A

0.5V

1.3k

AD707

43

20k

0.1 F

–2V

1.3k

20k

649

ANALOG

IN B

0.5V

324

20

0.1 F

40

COMP

1

ENCODE A

ENCODE B

10

36

ENCODE

74ACT04

0.1 F

+5V

28

29

30

31

32

33

34

35

RZ1

RZ2

7, 20,

26, 39

–5V

1N4001

AD9058

(J-LEAD)

RZ1, RZ2 = 2,000

SIP (8-PKG)

8

8

AD8001

AD8001

Figure 48. AD8001 Driving a Dual A-to-D Converter

Driving A-to-D Converters

The AD8001 is well suited for driving high speed analog-to-

digital converters such as the AD9058. The AD9058 is a dual

8-bit 50 MSPS ADC. In the circuit below the AD8001 is shown

driving the inputs of the AD9058, which are configured for 0 V

to +2 V ranges. Bipolar input signals are buffered, amplified

(–2

×), and offset (by +1.0 V) into the proper input range of the

ADC. Using the AD9058’s internal +2 V reference connected

to both ADCs as shown in Figure 48 reduces the number of

external components required to create a complete data

acquisition system. The 20

Ω resistors in series with ADC in-

puts are used to help the AD8001s drive the 10 pF ADC input

capacitance. The AD8001 only adds 100 mW to the power

consumption while not limiting the performance of the circuit.