AD674B/AD774B
PIN CONFIGURATION
V
1
2
STS
28
LOGIC
27 DB11 (MSB)
26 DB10
12/8
3
CS
4
A
25 DB9
0
AD674B
OR
5
24 DB8
R/C
6
23
22
21
20
19
18
17
16
15
CE
DB7
AD774B
7
V
DB6
CC
TOPVIEW
(Not to Scale)
8
REF OUT
AGND
DB5
9
DB4
10
11
12
13
14
REF IN
DB3
V
DB2
EE
BIP OFF
DB1
10V
DB0 (LSB)
DGND
IN
IN
20V
PIN FUNCTION DESCRIPTIONS
Pin No. Type* Name and Function
Symbol
AGND
A0
9
4
P
DI
Analog Ground (Common)
Byte Address/Short Cycle. If a conversion is started with A0 Active LOW, a full 12-bit conversion
cycle is initiated. If A0 is Active HIGH during a convert start, a shorter 8-bit conversion cycle
results. During Read (R/C = 1) with 12/8 LOW, A0 = LOW enables the 8 most significant bits,
and A0 = HIGH enables DB3–DB0 and sets DB7–DB4 = 0.
BIP OFF
12
AI
Bipolar Offset. Connect through a 50 Ω resistor to REF OUT for bipolar operation or to Analog
Common for unipolar operation.
CE
6
3
DI
DI
Chip Enable. Chip Enable is Active HIGH and is used to initiate a convert or read operation.
CS
Chip Select. Chip Select is Active LOW.
DB11–DB8 27–24
DO
Data Bits 11 through 8. In the 12-bit format (see 12/8 and A0 pins) these pins provide the upper
4 bits of data. In the 8-bit format, they provide the upper 4 bits when A0 is LOW and are
disabled when A0 is HIGH.
DB7–DB4 23–20
DB3–DB0 19–16
DO
DO
Data Bits 7 through 4. In the 12-bit format these pins provide the middle 4 bits of data. In the
8-bit format they provide the middle 4 bits when A0 is LOW and all zeroes when A0 is HIGH.
Data Bits 3 through 0. In both the 12-bit and 8-bit format these pins provide the lower 4 bits of
data when A0 is HIGH; they are disabled when A0 is LOW.
DGND
REF OUT
R/C
15
8
P
Digital Ground (Common)
AO
DI
10 V Reference Output
5
Read/Convert. In the full control mode R/C is Active HIGH for a read operation and Active LOW
for a convert operation. In the standalone mode, the falling edge of R/C initiates a conversion.
Reference Input is connected through a 50 Ω resistor to +10 V Reference for normal operation.
REF IN
STS
10
28
AI
DO
Status is Active HIGH when a conversion is in progress and goes LOW when the conversion is
completed.
VCC
7
P
+12 V/+15 V Analog Supply
VEE
11
1
P
–12 V/–15 V Analog Supply
VLOGIC
10 VIN
P
5 V Logic Supply
13
AI
10 V Span Input, 0 V to +10 V unipolar mode or –5 V to +5 V bipolar mode. When using the
20 V Span, 10 VIN should not be connected.
20 VIN
14
2
AI
20 V Span Input, 0 V to +20 V unipolar mode or –10 V to +10 V bipolar mode. When using the
10 V Span, 20 VIN should not be connected.
The 12/8 pin determines whether the digital output data is to be organized as two 8-bit words
(12/8 LOW) or a single 12-bit word (12/8 HIGH).
12/8
DI
*Types: AI = Analog Input, AO = Analog Output, DI = Digital Input, DO = Digital Output, P = Power
–6–
REV. C
ADI [ ADI ]
