Analog Devices AD4131-8 Product Info

The AD4131-8 is an ultra-low power, high precision, measurement solution for low bandwidth battery operated applications. The fully integrated analog front end (AFE) includes a multiplexer for up to 16 single-ended or eight differential inputs, programmable gain amplifier (PGA), 16-bit sigma-delta (∑-Δ) analog-to-digital converter (ADC), on-chip reference and oscillator, selectable filter options, flexible sequencer, sensor biasing and excitation options, diagnostics, and newly added features to improve the battery-operated lifetime (duty cycling).

The AD4131-8 allows users to measure low frequency signals with a current consumption of 28.5 µA (gain = 1) and 32.5 µA (gain = 128) while continuously converting, and even lower average currents when using one of the duty cycling options. The AD4131-8 can be configured to have eight differential inputs or 16 single-ended or pseudodifferential inputs, which connect to a crosspoint multiplexer, where any input pair can become a measurement channel input to the PGA and ADC.

The AD4131-8 is designed to allow the user to operate from a single analog supply voltage from 1.71 V to 3.6 V. In battery applications, operation as low as 1.71 V can extend the system lifetime as the AFE can continue its operation, even as the battery voltage dissipates. The digital supply can be separate and range from 1.65 V to 3.6 V.

The following key analog functions are offered on the AD4131-8 to allow simple and effective connection to transducers used for measuring temperature, load, and pressure:

• PGA. Due to the programmable gain (from 1 to 128) and the high input impedance with low input current, the PGA allows direct interfacing to transducers with low output amplitudes like resistive bridges, thermocouples, and resistance temperature detectors (RTDs).
• The capacitive PGA allows full common-mode input range, giving designers greater margin f