AD7739 Datasheet, PDF (13/32 Pages) Analog Devices – 8-Channel, High Throughput, 24-Bit Sigma-Delta ADC

Pin No.
8
9–16
17
18
19
20
21
22
23
24
Mnemonic
SYNC/P1
AIN0–AIN7
REFIN(+)
REFIN(–)
AGND
RDY
DOUT
DIN
DVDD
DGND
AD7739
Description
SYNC/Digital Input/Digital Output. The pin direction is determined by the P1 DIR bit;
the digital value can be read/written as the P1 bit in the I/O port register. When the SYNC
bit in the I/O port register is set to 1, then the SYNC/P1 pin can be used to synchronize
the AD7739 modulator and digital filter with other devices in the system. The digital
voltage is referenced to the analog supplies. When configured as an input, the pin should
be tied high or low.
Analog Inputs.
Positive Terminal of the Differential Reference Input. REFIN(+) voltage potential can lie
anywhere between AVDD and AGND. In normal circuit configuration, this pin should be
connected to a 2.5 V reference voltage.
Negative Terminal of the Differential Reference Input. REFIN(–) voltage potential can lie
anywhere between AVDD and AGND. In normal circuit configuration, this pin should be
connected to a 0 V reference voltage.
Ground Reference Point for Analog Circuitry.
Logic Output. Used as a status output in both conversion mode and calibration mode. In
conversion mode, a falling edge on this output indicates that either any channel or all
channels have unread data available, according to the RDYFN bit in the I/O port register.
In calibration mode, a falling edge on this output indicates that calibration is complete
(see the Digital Interface Description section for details).
Serial Data Output. Serial data is read from the output shift register on the part. This
output shift register can contain information from any AD7739 register, depending on
the address bits of the communications register.
Serial Data Input (Schmitt Triggered). Serial data is written to the input shift register on
the part. Data from this input shift register is transferred to any AD7739 register,
depending on the address bits of the communications register.
Digital Supply Voltage, 3 V or 5 V Nominal.
Ground Reference Point for Digital Circuitry.
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