24-Bit, 250 kSPS Sigma-Delta ADC
with 20 µs Settling
Fast and flexible output rate—5 SPS to 250 kSPS
Fast settling time—20 µs
Channel scan data rate of 50 kSPS/channel
17 noise free bits at 250 kSPS
20 noise free bits at 2.5 kSPS
22 noise free bits at 5 SPS
INL ±2.5 ppm of FSR
85 dB rejection of 50 Hz and 60 Hz with 50 ms settling
User-configurable input channels
2 fully differential or 4 pseudo differential
On-chip 2.5 V reference (drift 2 ppm/°C)
Internal oscillator, external crystal, or external clock
Single supply: 5 V AVDD1, 2 V to 5 V AVDD2 and IOVDD
Optional split supply: AVDD1 and AVSS ± 2.5 V
Current: 7.8 mA
Temperature range: −40°C to +105°C
3- or 4-wire serial digital interface (Schmitt trigger on SCLK)
CRC error checking
SPI, QSPI, MICROWIRE, and DSP compatible
Process control: PLC/DCS modules
Temperature and pressure measurement
Medical and scientific multichannel instrumentation
The AD7176-2 is a fast settling, highly accurate, high resolution,
multiplexed Σ-Δ analog-to-digital converter (ADC) for low band-
width input signals. Its inputs can be configured as two fully
differential or four pseudo differential inputs via the integrated
crosspoint multiplexer. An integrated precision, 2.5 V, low drift
(2 ppm/°C), band gap internal reference (with an output
reference buffer) adds functionality and reduces the external
The maximum channel scan data rate is 50 kSPS/channel
(settling time of 20 µs), resulting in fully settled data with
17 noise free bits. User-selectable output data rates range from
5 SPS to 250 kSPS. The resolution increases at lower speeds.
The AD7176-2 offers three key digital filters. The fast settling
sinc5 + sinc1 filter maximizes the channel scan rate. The sinc3
filter maximizes the resolution for single-channel, low speed
applications. For 50 Hz and 60 Hz environments, the AD7176-2
specific filter minimizes the settling times or maximizes the
rejection of the line frequency. These enhanced filters enable
simultaneous 50 Hz and 60 Hz rejection with a 27 SPS output
data rate (with a settling time of 36 ms).
System offset and gain errors can be corrected on a per channel
basis. This per channel configurability extends to the output data
rate used for each channel when using a sinc5 + sinc1 filter. All
switching of the crosspoint multiplexer is controlled by the ADC
and can be configured to automatically control an external
multiplexer via the GPIO pins.
The specified operating temperature range is −40°C to +105°C.
The AD7176-2 is housed in a 24-lead TSSOP package.
FUNCTIONAL BLOCK DIAGRAM
AVDD1 AVDD2 REGCAPA REF– REF+ REFOUT
XTAL AND INTERNAL
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