AD7709

–8–

REV. PrA

January 2001

PRELIMINARY TECHNICAL DATA

PIN CONFIGURATION

Pin Function Description

Pin No

Mnemonic

Function

1

IOUT1

Output for internal excitation current sources. A single current source or any

combination of the internal current sources I1,I2 and I3 can be switched to this

output.

2

IOUT2

Output for internal excitation current sources. A single current source or any

combination of the internal current sources I1,I2 and I3 can be switched to this

output.

3

REFIN1(+)

The nominal reference voltage (REFIN(+)-REFIN(-)) is 2.5V but the part is

4

REFIN1(-)

Negative reference input. This reference input can lie anywhere between GND

5

AIN1

Analog Input Channel 1. Programmable-gain analog input which can be used

as a pseudo-differential input when used with AINCOM or as the positive in-

put of a fully-differential input pair when used with AIN2. (see Communica-

tions Register section)

6

AIN2

Analog Input Channel 2. Programmable-gain analog input which can be used

as a pseudo-differential input when used with AINCOM or as the negative

input of a fully-differential input pair when used with AIN1. (see Communica-

tions Register section)

7

AIN3/P3

Analog Input Channel 3 or Digital Port Bit. Programmable-gain analog input

which can be used as a pseudo-differential input when used with AINCOM or

as the positive input of a fully-differential input pair when used with AIN4.

The second function of this bit is as a general purpose digital input bit.

8

AIN4/P4

Analog Input Channel 4 or digital port bit. Programmable-gain analog input

which can be used as a pseudo-differential input when used with AINCOM or

as the negative input of a fully-differential input pair when used with AIN3.

The second function of this bit is as a general purpose digital input bit.

9

AINCOM

All analog inputs are referenced to this input when configured in pseudo-dif-

ferential input mode.

10

REFIN2(+)

The nominal reference voltage (REFIN2(+)-REFIN2(-)) is 2.5V but the part

TO P V IEW

(No t to S cale)

SCL K

CS

R E SET

AIN1

AINCO M

GN D

DIN

DO UT

DRDY

REFIN1(-)

REFIN1(+ )

AD7709

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

XTA L1

AIN3/P 3

AIN 2

21

22

23

24

AIN4/P 4

REFIN2(+ )

P2/S W 2

PW R G N D

P1/S W 1

XTA L2

IO UT 1

IO UT 2

REFIN2(-)