AD7264

Rev. A | Page 18 of 32

100nF

3V OR 5V

SUPPLY

MICROPROCESSOR/

MICROCONTROLLER

COMPARATOR

BOTH

COMPARATORS

AND ADCs

POWERED ON

100nF

100nF

100nF

ANALOG

SUPPLY

+5V

100nF

100nF

100nF

100nF

G0

G1

G2

G3

SCLK

REFSEL

CAL

PD1

PD2

13 14 15 16

45 46 47 48

25 26 29 30

22

23

36

24

32

35

34

37

38

39

40

27

31

21

1µF

1µF

17 44 5 6 8 19 42 28 2 7 11 20 41 12 1 33

10

9

18

43

4

3

AD7264

FAST PROPAGATION DELAY

COMPARATOR INPUTS

LOW POWER

COMPARATOR INPUTS

SERIAL

INTERFACE

GAIN 2

SETUP

CONNECT

DIRECTLY

TO SENSOR

OUTPUTS

THIS REFERENCE SIGNAL

MUST BE BUFFERED

BEFORE IT CAN BE

USED ELSEWHERE IN

THE CIRCUIT

GAIN 2

GAIN 2

GAIN 2

GAIN 2

CONNECT

DIRECTLY

TO SENSOR

OUTPUTS

CS

3.125V

2.500V

1.875V

3.125V

2.500V

1.875V

3.125V

2.500V

1.875V

3.125V

2.500V

1.875V

Figure 27. Typical Connection Diagram for the AD7264 in Pin Driven Mode with Gain of 2 and Both ADCs and Comparators Fully Powered On

Comparator Application Details

The comparators on the AD7264 have been designed with no

internal hysteresis, allowing users the flexibility to add external

hysteretic if required for systems operating in noisy environments.

If the comparators on the AD7264 are used with external hyste-

resis, some external resistors and capacitors are required, as

can be determined using the following equation, depending on

the amount of hysteresis required in the application:

CC

X

F

S

S

HYS

V

C

C

R

R

R

V

_

X

×

+

=

The amount of hysteresis chosen must be sufficient to eliminate

the effects of analog noise at the comparator inputs, which may

affect the stability of the comparator outputs. The level of

hysteresis required in any system depends on the noise in the

to eliminate any noise effects. To increase the level of hysteresis in

a load capacitor (100 pF) may be required on the comparator

outputs to suppress high frequency transient glitches.