The LTC2420 is a micropower 20-bit A/D converter with an integrated oscillator, 8ppm INL and 1.2ppm RMS noise that operates from 2.7V to 5.5V. It uses delta-sigma technology and provides a digital filter that settles in a single cycle for multiplexed applications. Through a single pin, the LTC2420 can be configured for better than 110dB rejection at 50Hz or 60Hz 2%, or it can be driven by an external oscillator for a user-defined rejection frequency in the range 1Hz to 800Hz. The internal oscillator requires no external frequency setting components.