1k

Offset

Adjust

8 11

AGND

ADC08B200

D7

D6

D5

D0

D1

D2

D3

D4

6

3

5

30

DR GND

10

V

RT

V

IN

2

46

CLK

9

0.1 µF

10 µF

+

1

4

32

0.1 µF

10 µF

V

DR

V

A

Choke

0.1 µF

10 µF

+

12

+3.3V

7

V GND

IN

38

MUL0

39

MUL1

BSIZE0

BSIZE1

24

23

DRDY

31

OE

40

OEDGE

14

EF

15

FF

16

REN

20

WEN

17

21 42 45 47

43 44 48

+

10 µF

0.1 µF

V

P

RCLK

19

ASW

25

18

WENsync

37

RESET

22

V

D

PD

13

26

27

28

36

35

34

33

29

PDADC

41

V

RM

V

RB

22

+

-

200

12

240

47

100

10 pF

Signal

Input

LMH6702

+5V

-5V

0.1µF

0.1 µF

10

Gain Adjust

4.7k

1k

0.33 µF

+3.3V

*

*

*

Ground connections marked

with "*" should enter the

ground

plane at a common point.

*

ADC08B200

www.ti.com

SNAS388F – MARCH 2007 – REVISED APRIL 2013

Figure 46. The Input Amplifier Should Incorporate Some Gain for Best Performance (see text)

POWER SUPPLY CONSIDERATIONS

A/D converters draw sufficient transient current to corrupt their own power supplies if not adequately bypassed.

Generally, a 10 µF tantalum or aluminum electrolytic capacitor should be provided for each of the four supplies

and a 0.1 µF ceramic chip capacitor placed within one centimeter of each converter power supply pin.

To further lower the inductance in series with the capacitors, mount the 0.1 µF capacitors on the same side of

the board as the ADC and use 2 to 4 closely spaced through holes to connect the ground side of the capacitors

to the ground plane. The through holes used to ground one side of these capacitors should not be used to

connect anything else to ground. Leadless chip capacitors are preferred because they have low lead inductance.

pins should be well isolated from the other supply pins to prevent any digital noise from being coupled into the

adequate bypass capacitors close to each supply pin, as shown in Figure 44, Figure 45 and Figure 46.

As is the case with all high speed converters, the ADC08B200 should be assumed to have little power supply

rejection. None of the supplies for the converter should be the supply that is used for other digital circuitry in any

system with a lot of digital power being consumed. The ADC supplies should be the same supply used for other

analog circuitry.

No pin should ever have a voltage on it that is in excess of the supply voltage or below ground by more than 300

mV, not even on a transient basis. This can be a problem upon application of power and power shut-down. Be

sure that the supplies to circuits driving any of the input pins, analog or digital, do not come up any faster than

does the voltage at the ADC08B200 power pins.

Copyright © 2007–2013, Texas Instruments Incorporated

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