Features

• Low Supply Current (200µA in Conversion Mode and 4µA in Autosleep Mode)
• Differential Input and Differential Reference with GND to V_CC Common Mode Range
• 3ppm INL, No Missing Codes
• 10ppm Full-Scale Error and 1ppm Offset
• 0.56ppm Noise, 20.8 ENOBs
• No Latency: Digital Filter Settles in a Single Cycle. Each Conversion Is Accurate, Even After an Input Step
• Single Supply 2.7V to 5.5V Operation
• Internal Oscillator—No External Components Required
• 110dB Min, 50Hz/60Hz Notch Filter
• Pin Compatible with 24-Bit LTC2410/LTC2411

Typical Application

Description

The LTC2430/LTC2431 are 2.7V to 5.5V micropower 20-bit differential Delta Sigma 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 V_CC for flexible ratiometric and remote sensing measurement configurations. The fullscale differential input range is from –0.5V_REF to 0.5V_REF. The reference common mode voltage, V_REFCM, and the input common mode voltage, V_INCM, may be independently set anywhere within GND to V_CC. 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 MICROWIRE protocols.