AD1671

REV. B

–4–

PIN DESCRIPTION

Symbol

Pin No.

Type

Name and Function

ACOM

27

P

Analog Ground.

AIN

22, 23

AI

Analog Inputs, AIN1 and AIN2. The AD1671 can be pin strapped for four input ranges:

Range

Pin Strap

Signal Input

0 to +2.5 V,

±2.5 V

Connect AIN1 to AIN2

AIN1 or AIN2

0 to +5 V,

±5 V

Connect AIN1 or AIN2 to ACOM

AIN1 or AIN2

BIT 1 (MSB)

13

DO

Most Significant Bit.

BIT 2–BIT 11

12-3

DO

Data Bits 2 through 11.

BIT 12 (LSB)

2

DO

Least Significant Bit.

BPO/UPO

26

AI

Bipolar or Unipolar Configuration Pin. See section on Input Range Connections for details.

DAV

16

DO

Data Available Output. The rising edge of DAV indicates an end of conversion and can be used

to latch current data into an external register. The falling edge of DAV can be used to latch

previous dam into an external register.

DCOM

19

P

Digital Ground.

ENCODE

17

DI

The analog input is sampled on the rising edge of ENCODE.

MSB

14

DO

Inverted Most Significant Bit. Provides twos complement output data format.

OTR

15

DO

Out of Range is Active HIGH when the analog input is out of range. See Output Data Format,

Table III.

REF COM

20

AI

REF COM is the internal reference ground pin. REF COM should be connected as indicated

in the Grounding and Decoupling Rules and Optional External Reference Connection Sections.

REF IN

24

AI

REF IN is the external 2.5 V reference input.

REF OUT

21

AO

REF OUT is the internal 2.5 V reference output.

SHA OUT

25

AO

No Connect for bipolar input ranges. Connect SHA OUT to BPO/UPO for unipolar input ranges.

28

P

+5 V Analog Power.

1

P

–5 V Analog Power.

18

P

+5 V Digital Power.

TYPE: AI = Analog Input; AO = Analog Output; DI = Digital Input; DO = Digital Outputs; P = Power.

PIN CONFIGURATION

ACOM

BPO/UPO

DCOM

ENCODE

DAV

OTR

MSB

BIT 12 (LSB)

BIT 11

BIT 10

BIT 9

BIT 8

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1 (MSB)

AIN1

REF COM

REF OUT

AIN2

SHA OUT

1

2

3

7

28

27

26

22

8

9

10

21

20

19

11

12

18

17

4

5

25

24

6

23

TOP VIEW

(Not to Scale)

13

14

16

15

AD1671

V

LOGIC

REF IN