8-Channel, 4.8 kHz, Ultralow Noise, 24-Bit Sigma-Delta ADC with PGA

The AD7194 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). The on-chip low noise gain stage means that signals of small amplitude can interface directly to the ADC.

The device can be configured to have eight differential inputs or sixteen pseudo differential inputs. 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 a very flexible digital filter, including a fast settling option. Variables such as output data rate and settling time are dependent on the option selected. For applications that require all conversions to be settled, the AD7194 includes zero latency.

The part operates with a power supply from 3 V to 5.25 V. It consumes a current of 4.65 mA, and it is housed in a 32-lead LFCSP package.

Applications

* PLC/DCS analog input modules

* Data acquisition

* Strain gage transducers

* Pressure measurement

* Temperature measurement

* Flow measurement

* Weigh scales

* Chromatography

* Medical and scientific instrumentation

* Fast settling filter option

* 8 differential/16 pseudo differential input channels

* RMS noise: 11 nV at 4.7 Hz (gain = 128)

* 15.5 noise-free bits at 2.4 kHz (gain = 128)

* Up to 22 noise-free bits (gain = 1)

* Offset drift: ±5 nV/°C

* Gain drift: ±1 ppm/°C

* 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: 3 V to 5.25 V

* DVDD: 2.7 V to 5.25 V

* Current: 4.65 mA

* Temperature range: −40°C to +105°C

* Package: 32-lead LFCSP

* Interface

* 3-wire serial

* SPI, QSPI™, MICROWIRE™, and DSP compatible

* Schmitt trigger on SCLK