The AD7858/AD7858L are high-speed, low-power, 12-bit ADCs that operate from a single 3 V or 5 V power supply, the AD7858 being optimized for speed and the AD7858L for low power. The ADC powers up with a set of default conditions at which time it can be operated as a read-only ADC. The ADC contains self-calibration and system calibration options to ensure accurate operation over time and temperature and have a number of power-down options for low-power applications. The part powers up with a set of default conditions and can operate as a read-only ADC.