AD7890

–6–

REV. A

PIN CONFIGURATION

DIP and SOIC

AGND

SMODE

REF OUT/REF IN

CONVST

CLK IN

SCLK

DGND

TFS

RFS

DATA OUT

AGND

DATA IN

SHA IN

MUX OUT

14

1

2

24

23

5

6

7

20

19

18

3

4

22

21

8

17

9

16

10

15

11

TOP VIEW

(Not to Scale)

11

12

13

AD7890

Pin

Mnemonic

Description

17

Analog Input Channel 2. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

18

Analog Input Channel 3. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

19

Analog Input Channel 4. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

20

Analog Input Channel 5. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

21

Analog Input Channel 6. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

22

Analog Input Channel 7. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

23

Analog Input Channel 8. Single-ended analog input. The analog input range on is

±10 V (AD7890-

10), 0 V to +4.096 V (AD7890-4) and 0 V to +2.5 V (AD7890-2). The channel to be converted is

selected using the A0, A1 and A2 bits in the control register. The multiplexer has guaranteed

break-before-make operation.

24

REF OUT/REF IN

Voltage Reference Output/Input. The part can be used with either its own internal reference or with

an external reference source. The on-chip +2.5 V reference voltage is provided at this pin. When

using this internal reference as the reference source for the part, REF OUT should decoupled to

AGND with a 0.1

µF disc ceramic capacitor. The output impedance of this reference source is typi-

cally 2 k

Ω. When using an external reference source as the reference voltage for the part, the refer-

ence source should be connected to this pin. This overdrives the internal reference and provides the

reference source for the part. The REF IN input is buffered on-chip. The nominal reference voltage

for correct operation of the AD7890 is +2.5 V.