AD674 AD [Analog Devices], AD674 Datasheet - Page 6

• Manufacturer Part Number: AD674
• Description: Complete 12-Bit A/D Converters
• Manufacturer: AD [Analog Devices]

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