Datasheet AD1674 (Analog Devices) - 8

AD1674 PIN DESCRIPTION Symbol Pin No. Type Name and Function
AGND 9 P Analog Ground (Common). A0 4 DI 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 (DB4–DB11), 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 DI Chip Enable. Chip Enable is Active HIGH and is used to initiate a convert or read operation. CS 3 DI 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 up- per 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 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 Ao is LOW and all zeroes when A0 is HIGH. DB3–DB0 19–16 DO Data Bits 3 through 0. In the 12-bit format these pins provide the lower 4 bits of data. In the 8-bit format these pins provide the lower 4 bits of data when A0 is HIGH, they are disabled when A0 is LOW. DGND 15 P Digital Ground (Common). REF OUT 8 AO +10 V Reference Output. R/C 5 DI 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 stand-alone mode, the falling edge of R/C initiates a conversion. REF IN 10 AI Reference Input is connected through a 50 Ω resistor to +10 V Reference for normal operation. STS 28 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 P –12 V/–15 V Analog Supply. VLOGIC 1 P +5 V Logic Supply. 10 VIN 13 AI 10 V Span Input, 0 V to +10 V unipolar mode or –5 V to +5 V bipolar mode. When using the AD1674 in the 20 V Span 10 VIN should not be connected. 20 VIN 14 AI 20 V Span Input, 0 V to +20 V unipolar mode or –10 V to +10 V bipolar mode. When using the AD1674 in the 10 V Span 20 VIN should not be connected. 12/8 2 DI 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). TYPE: AI = Analog Input AO = Analog Output
FUNCTIONAL BLOCK DIAGRAM PIN CONFIGURATION
DI = Digital Input DO = Digital Output P = Power
12/8 V 1 28 LOGIC STS CS STS 12/8 2 27 DB11(MSB) A CONTROL 0 CS 3 26 DB10 CE
A
A 4 25 R/C 0 DB9
AA
R/C 5 24 DB8 10V
A
CE 6 23 DB7 CLOCK REF
AA AA
REF OUT SAR AD1674 12
AA AA AA A
V 7 22 DB6 CC TOP VIEW REF OUT 8 21 DB5 (Not to Scale) AGND DB11 (MSB) AGND 9 20 DB4 COMP 20k 12 DB0 (LSB) REF IN 10 19 DB3 REF IN 12
A
5k 10k V 11 18 EE DB2 BIP OFF BIP OFF 12 17 DB1 20VIN 10k DAC
A
10V 13 16 DB0(LSB) 5k IN 10V IDAC 20V 14 15 IN DGND IN 2.5k 5k
A
REGISTERS / 3-STATE OUTPUT BUFFERS 2.5k SHA AD1674
REV. C –7–