Data Sheet AD7171
Rev. C | Page 7 of 16
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
08417-005
NOTES
1. CONNECT EXPOSED PAD TO GROUND.
SCLK
AIN(+)
AIN(–)
REFIN(+)
GND
V
DD
GND
REFIN(–)
PDRST
DOUT/RDY
1
2
3
4
5
10
9
8
7
6
AD7171
TOP VIEW
(Not to Scale)
Figure 5. Pin Configuration
Table 6. Pin Function Descriptions
Pin No. Mnemonic Description
1 SCLK
Serial Clock Input. This serial clock input is for data transfers from the ADC. The SCLK has a Schmitt-triggered
input. The serial clock can be continuous with all data transmitted in a constant train of pulses. Alternatively, it
can be a noncontinuous clock with the information being transmitted from the ADC in smaller batches of data.
2
DOUT/
RDY Serial Data Output/Data Ready Output. DOUT/RDY serves a dual purpose. DOUT/RDY operates as a data ready
pin, going low to indicate the completion of a conversion. In addition, it functions as a serial data output pin to
access the data register of the ADC. Eight status bits accompany each data read. See
Figure 13 for further details.
The DOUT/RDY falling edge can be used as an interrupt to a processor, indicating that new data is available. If
the data is not read after the conversion, the pin goes high before the next update occurs.
3 AIN(+) Analog Input. AIN(+) is the positive terminal of the differential analog input pair AIN(+)/AIN(−).
4 AIN(−) Analog Input. AIN(−) is the negative terminal of the differential analog input pair AIN(+)/AIN(−).
5 REFIN(+)
Positive Reference Input. An external reference can be applied between REFIN(+) and REFIN(–). The nominal
reference voltage (REFIN(+) − REFIN(−)) is 5 V, but the device can function with a reference of 0.5 V to V
DD
.
Negative Reference Input.
7, 10 GND Ground Reference Point.
8 V
DD
Supply Voltage, 2.7 V to 5.25 V.
9
PDRST Power-Down/Reset. When this pin is low, the ADC is placed in power-down mode. All the logic on the chip is
reset and the DOUT/
RDY pin is tristated. When PDRST is high, the ADC is taken out of power-down mode. The
on-chip clock powers up and settles, and the ADC continuously converts. The internal clock requires 1 ms
approximately to power up.
EPAD Exposed Pad. Connect exposed pad to ground.
