Low Power, 8-/16-Channel, 31.25 kSPS,
24-Bit, Highly Integrated Sigma-Delta ADC
AD7173-8
Data Sheet
APPLICATIONS
FEATURES
Process control: PLC/DCS modules
Voltage, current, temperature, and pressure measurement
Flow meters
Low power, 8-/16-channel, highly integrated multiplexed
analog-to-digital converter (ADC)
Integration
Medical and scientific multichannel instrumentation
Seismic instrumentation
Chemical analysis instrumentation: chromatography
Precision analog input buffers and reference input buffers
2.5 V precision reference (3.5 ppm/°C)
Cross point multiplexer (enable system diagnostic)
8 full differential or 16 single-ended channels
Clock oscillator
GPIO and GPO pins with automatic external mux control
Fast and flexible output rate: 1.25 SPS to 31.25 kSPS
Channel scan data rate: 6.21 kSPS/channel (161 µs settling)
Performance specifications
GENERAL DESCRIPTION
Fast settling, highly accurate, low power, 8-/16-channel,
multiplexed ADC for low bandwidth input signals with
integrated input buffers.
Integrated precision, 2.5 V, low drift (3.5 ppm/°C), band gap
reference and integrated oscillator.
17.5 noise free bits at 31.25 kSPS
24 noise free bits at 1.25 SPS
INL: 3 ppm/FSR
Eight flexible setups with configurability for output data rate,
digital filter mode, offset/gain error correction, reference
selection, buffer enables and more.
85 dB rejection of 50 Hz and 60 Hz with 50 ms settling
Operates with either 3.3 V or5 V supply
Single supply
3.3 V or 5 V AVDD1, 2 V to 5 V AVDD2, and 2 V to 5 V IOVDD
Optional split supply
Sinc5 + sinc1 filter maximizes channel scan rate, and sinc3 filter
maximizes resolution and enhanced 50 Hz/60 Hz rejection,
with four selectable options to maximize rejection.
Integrated diagnostic features, including CRC, register checksum,
temperature sensor, crosspoint multiplexer, burnout currents,
and GPIOs/GPOs.
AVDD1 and AVSS 2.5 V or AVDD1 and AVSS 1.65 V
Current: 1.4 mA
3-/4-wire serial digital interface (Schmitt trigger on SCLK)
CRC error checking
SPI, QSPI, MICROWIRE, and DSP compatible
Package: 40-lead 6 mm × 6 mm LFCSP
Temperature range: −40°C to +105°C
FUNCTIONAL BLOCK DIAGRAM
AVDD1 AVDD2 REGCAPA
REF– REF+ REFOUT
IOVDD REGCAPD
BUFFERED
1.8V
LDO
1.8V
LDO
PRECISION
REFERENCE
REFERENCE
CROSSPOINT
MULTIPLEXER
INPUT
BUFFERS
INT
REF
AIN0/REF2–
AIN1/REF2+
AVDD
ANALOG
INPUT
BUFFERS
CS
SCLK
DIN
SERIAL
INTERFACE
AND CONTROL
DIGITAL
FILTER
Σ-Δ ADC
DOUT/RDY
SYNC
ERROR
AIN15
AIN16
XTAL AND INTERNAL
CLOCK OSCILLATOR
CIRCUITRY
AVSS
I/O CONTROL
AD7173-8
TEMPERATURE
SENSOR
AVSS
PDSW
GPIO0 GPIO1 GPIO2 GPIO3
XTAL1 XTAL2/CLKIO
DGND
Figure 1.
Rev. 0
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