AD7190_08 Datasheet, PDF (1/40 Pages) Analog Devices – 4.8 kHz Ultralow Noise 24-Bit Sigma-Delta ADC with PGA

4.8 kHz Ultralow Noise 24-Bit
Sigma-Delta ADC with PGA
AD7190
FEATURES
RMS noise: 8.5 nV @ 4.7 Hz (gain = 128)
16 noise free bits @ 2.4 kHz (gain = 128)
Up to 22.5 noise free bits (gain = 1)
Offset drift: 5 nV/°C
Gain drift: 1 ppm/°C
Specified drift over time
2 differential/4 pseudo differential input channels
Automatic channel sequencer
Programmable gain (1 to 128)
Output data rate: 4.7 Hz to 4.8 kHz
Internal or external clock
Simultaneous 50 Hz/60 Hz rejection
4 general-purpose digital outputs
Power supply
AVDD: 4.75 V to 5.25 V
DVDD: 2.7 V to 5.25 V
Current: 6 mA
Temperature range: –40°C to +105°C
Interface
3-wire serial
SPI, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on SCLK
APPLICATIONS
Weigh scales
Strain gauge transducers
Pressure measurement
Temperature measurement
Chromatography
PLC/DCS analog input modules
Data acquisition
Medical and scientific instrumentation
GENERAL DESCRIPTION
The AD7190 is a low noise, complete analog front end for high
precision measurement applications. It contains a low noise,
24-bit sigma-delta (∑-Δ) analog to digital converter (ADC).
The on-chip low noise gain stage means that signals of small
amplitude can be interfaced directly to the ADC.
The device can be configured to have two differential inputs or
four pseudo differential inputs. The on-chip channel sequencer
allows several channels to be enabled, and the AD7190
sequentially converts on each enabled channel. This simplifies
communication with the part. The on-chip 4.92 MHz clock can
be used as the clock source to the ADC or, alternatively, an
external clock or crystal can be used. The output data rate from
the part can be varied from 4.7 Hz to 4.8 kHz.
The device has two digital filter options. The choice of filter
affects the rms noise/noise-free resolution at the programmed
output data rate, the settling time, and the 50 Hz/60 Hz
rejection. For applications that require all conversions to be
settled, the AD7190 includes a zero latency feature.
The part operates with 5 V analog power supply and a digital
power supply from 2.7 V to 5.25 V. It consumes a current of
6 mA. It is housed in a 24-lead TSSOP package.
FUNCTIONAL BLOCK DIAGRAM
AGND AV_DD
DV_DD DGND REFIN1(+) REFIN1(–)
AIN1
AIN2
AIN3
AIN4
AINCOM
BPDSW
AD7190
REFERENCE
DETECT
MUX
AGND
PGA
Σ-Δ
ADC
TEMP
SENSOR
CLOCK
CIRCUITRY
SERIAL
INTERFACE
AND
CONTROL
LOGIC
DOUT/RDY
DIN
SCLK
CS
SYNC
P3
P2
MCLK1 MCLK2 P0/REFIN2(–) P1/REFIN2(+)
Figure 1.
Rev. 0
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