Datasheet
AD7912/AD7922
Rev. 0 | Page 10 of 32
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
04351-0-008
V
DD
GND
V
IN0
V
IN1
8
7
6
5
DOUT
1
CS
2
SCLK
3
DIN
4
AD7912/
AD7922
8-LEAD MSOP
TOP VIEW
(Not to Scale)
Figure 8. 8-Lead MSOP Pin Configuration
04351-0-009
V
IN1
V
IN0
GND
V
DD
8
7
6
5
DIN
1
SCLK
2
CS
3
DOUT
4
AD7912/
AD7922
8-LEAD TSOT
TOP VIEW
(Not to Scale)
Figure 9. 8-Lead TSOT Pin Configuration
Table 5. Pin Function Descriptions
MSOP
Pin No.
TSOT
Pin No. Mnemonic Function
1 4 DOUT
Data Out. Logic output. The conversion result from the AD7912/AD7922 is provided on this output as
a serial data stream. The bits are clocked out on the falling edge of the SCLK signal.
For the AD7922, the data stream consists of two leading zeros, the channel identifier bit that identifies
which channel the conversion result corresponds to, followed by the mode bit that indicates the
current mode of operation, followed by the 12 bits of conversion data with MSB first.
For the AD7912, the data stream consists of two leading zeros, the channel identifier bit that identifies
which channel the conversion result corresponds to, followed by the mode bit that indicates the
current mode of operation, followed by the 10 bits of conversion data with MSB first and two trailing
zeros.
2 3
CS
Chip Select. Active low logic input. This input provides the dual function of initiating conversions on
the AD7912/AD7922 and framing the serial data transfer.
3 2 SCLK
Serial Clock. Logic input. SCLK provides the serial clock for accessing data from the part. This clock
input is also used as the clock source for the AD7912/AD7922’s conversion process.
4 1 DIN
Data In. Logic input. The channel to be converted is provided on this input and is clocked into an
internal register on the falling edge of SCLK.
6, 5 7, 8 V
IN0
, V
IN1
Analog Inputs. These two single-ended analog input channels are multiplexed into the on-chip
track-and-hold amplifier. The analog input channel to be converted is selected by writing to the third
MSB on the DIN pin. The input range is 0 to V
DD
.
7 6 GND
Analog Ground. Ground reference point for all circuitry on the AD7912/AD7922. All analog input
signals should be referred to this GND voltage.
8 5 V
DD
Power Supply Input. The V
DD
range for the AD7912/AD7922 is from 2.35 V to 5.25 V.