The ADC used in this design is the ADS8689, a 16-bit successive approximation register (SAR) converter with integrated signal-chain consisting of a programmable gain amplifier (PGA) and a 2^nd-order low-pass filter (LPF). The ADS8689 accepts input voltages up ±12.288 V while only requiring a single 5-V power rail. The PGA allows a constant resolution across all voltage inputs ranges because its output always utilizes the entire ADC input range. The integrated LPF with a f_{CUT-OFF_-3dB} = 15 kHz limits signal settling time in a multiplexed design. The SAR converter can operate at a sample rate of up to 100 kSPS. The sampling rate is set by the processing unit via the serial interface CONVST/CS signal. The precision integrated 4.096-V voltage reference reduces board space and cost. The ADS8689 employs a simple SPI for seamless connection to standard microcontrollers and microprocessors. If isolation is required, refer to Digitally-isolated ADS8689 circuit design.