The AMC131M03 is an isolated, low-power, three-channel, simultaneous-sampling, 24-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC) with a low-drift internal voltage reference and an integrated DC/DC converter that allows the device to be supplied from a single 3.3-V or 5-V voltage supply source on the primary (low) side. The dynamic range, size, feature set, and power consumption are optimized for cost-sensitive applications requiring simultaneous sampling.

The silicon-dioxide (SiO₂)-based capacitive isolation barrier supports a high level of magnetic field immunity, as described in the ISO72x Digital Isolator Magnetic-Field Immunity application note.

An integrated negative charge pump allows absolute input voltages as low as 1.3 V below HGND, which enables measurements of input signals varying around ground with a single-ended power supply. The device features a programmable gain amplifier (PGA) with gains up to 128. An integrated input precharge buffer enabled at gains greater than 4 provides high input impedance at high PGA gain settings. The ADC receives the reference voltage from an integrated 1.2-V reference. The device allows differential input voltages as large as the reference. Two power-scaling modes allow designers to trade power consumption for ADC dynamic range.

Each ADC channel on the AMC131M03 contains a digital decimation filter that demodulates the output of the ΔΣ modulators. The filter enables data rates as high as 64 kSPS per channel in high-resolution mode. The relative phase of the samples can be configured between channels, thus enabling an accurate compensation for the sensor phase response. Offset and gain calibration registers can be programmed to automatically adjust output samples for measured offset and gain errors. The Functional Block Diagram provides a detailed diagram of the AMC131M03.

The device communicates via a serial programming interface (SPI)-compatible interface. Several SPI commands and internal registers control the operation of the AMC131M03. Other devices can be added to the same SPI bus by adding discrete CS control lines. The SYNC/RESET pin can synchronize conversions between multiple AMC131M03 devices and maintains synchronization with external events.