The LTC2430/LTC2431 are 2.7V to 5.5V micropower 20-bit differential analog-to-digital converters with an integrated oscillator, 3ppm INL and 0.56ppm RMS noise. They use delta-sigma technology and provide single cycle settling time for multiplexed applications. Through a single pin, the LTC2430/LTC2431 can be configured for better than 110dB differential mode rejection at 50Hz or 60Hz 2%, or they can be driven by an external oscillator for a user-defined rejection frequency. The internal oscillator requires no external frequency setting components. The converters accept any external differential reference voltage from 0.1V to VCC for flexible ratiometric and remote sensing measurement configurations. The fullscale differential input range is from 0.5VREF to 0.5VREF. The reference common mode voltage, VREFCM, and the input common mode voltage, VINCM, may be independently set anywhere within GND to VCC. The DC common mode input rejection is better than 120dB. The LTC2430/LTC2431 communicate through a flexible 3-wire digital interface that is compatible with SPI and MICROWIRETM protocols.