The MAX191 is a monolithic, CMOS, 12-bit analog-to-digital converter (ADC) featuring differential inputs, track/hold (T/H), internal voltage reference, internal or external clock, and parallel or serial µP interface. The MAX191 has a 7.5µs conversion time, a 2µs acquisition time, and a guaranteed 100ksps sample rate. The MAX191 operates from a single +5V supply or from dual ±5V supplies, allowing ground-referenced bipolar input signals. The device features a logic power-down input, which reduces the 3mA VDD supply current to 50µA max, including the internal-reference current. Decoupling capacitors are the only external components needed for the power supply and reference. This ADC operates with either an external reference, or an internal reference that features an adjustment input for trimming system gain errors. The MAX191 provides three interface modes: two 8-bit parallel modes, and a serial interface mode that is compatible with SPI, QSPI, and MICROWIRE serial-interface standards.