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. The AD7858 is capable of 200 kHz throughput rate while the AD7858L is capable of 100 kHz throughput rate. The input track-and-hold acquires a signal in 500 ns and features a pseudo-differential sampling scheme. The AD7858/AD7858L voltage range is 0 to VREF with straight binary output coding. Input signal range is to the supply and the part is capable of converting full power signals to 100 kHz. CMOS construction ensures low power dissipation of typically 4.5 mW for normal operation and 1.15 mW in power-down mode with a throughput rate of 10 kSPS （VDD = 3 V）。 The part is available in 24-lead， 0.3 inch-wide dual-in-line package （DIP）， 24-lead small outline （SOIC）， and 24-lead small shrink outline （SSOP） packages.