Datasheet
AD7892
REV. C
–7–
Pin
No. Mnemonic Description
16 DB4/SCLK Data Bit 4/Serial Clock. When the device is in its parallel mode, this pin is Data Bit 4, a three-state
TTL-compatible output. When the device is in its serial mode, this becomes the serial clock pin,
SCLK. SCLK is an input and an external serial clock must be provided at this pin to obtain serial
data from the AD7892. Serial data is clocked out from the output shift register on the rising edges
of SCLK after RFS goes low.
17 DB3/RFS Data Bit 3/Receive Frame Synchronization. When the device is in its parallel mode, this pin is Data
Bit 3, a three-state TTL-compatible output. When the device is in its serial mode, this becomes the
receive frame synchronization input with RFS provided externally to obtain serial data from the
AD7892.
18 DB2 Data Bit 2. Three-state TTL-compatible output. This output should be left unconnected when the
device is in its serial mode.
19 DB1 Data Bit 1. Three-state TTL-compatible output. This output should be left unconnected when the
device is in its serial mode.
20 DB0 Data Bit 0 (LSB). Three-state TTL-compatible output. Output coding is two’s complement for
AD7892-1 and AD7892-3 and straight (natural) binary for AD7892-2. This output should be left
unconnected when the device is in its serial mode.
21 RD Read. Active low logic input which is used in conjunction with CS low to enable the data outputs.
22 CS Chip Select. Active low logic input which is used in conjunction with RD to enable the data outputs.
23 EOC End-of-Conversion. Active low logic output indicating converter status. The end of conversion is
signified by a low going pulse on this line. The duration of this EOC pulse is nominally 100 ns.
24 CONVST Convert Start. Logic Input. A low-to-high transition on this input puts the track/hold into its hold
mode and starts conversion.
PIN CONFIGURATION
DIP and SOIC
V
DD
REF OUT/REF IN
AGND
MODE
DB0 (LSB)
DB1
DB2
V
IN2
V
IN1
DB11/LOW DB3/RFS
DB10/LOW
DB4/SCLK
DB9 DB5/SDATA
DB8
DGND
DB7 DB6
14
1
2
24
23
5
6
7
20
19
18
3
4
22
21
817
916
10 15
11
TOP VIEW
(Not to Scale)
11
12 13
AD7892
STANDBY
CONVST
EOC
CS
RD