Features

• 20-Bit ADC in SO-8 Package
• 8ppm INL, No Missing Codes at 20 Bits
• 4ppm Full-Scale Error
• 0.5ppm Offset
• 1.2ppm Noise
• Digital Filter Settles in a Single Cycle. Each Conversion Is Accurate, Even After an Input Step
• Fast Mode: 16-Bit Noise, 12 Bits TUE at 100sps
• Internal Oscillator—No External Components Required
• 110dB Min, 50Hz/60Hz Notch Filter
• Reference Input Voltage: 0.1V to V_CC
• Live Zero—Extended Input Range Accommodates 12.5% Overrange and Underrange
• Single Supply 2.7V to 5.5V Operation
• Low Supply Current (200µA) and Auto Shutdown
• Pin Compatible with 24-Bit LTC2400

Typical Application

Description

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. The converter accepts any external reference voltage from 0.1V to V_CC. With its extended input conversion range of –12.5% V_REF to 112.5% V_REF, the LTC2420 smoothly resolves the offset and overrange problems of preceding sensors or signal conditioning circuits. The LTC2420 communicates through a flexible 3-wire digital interface which is compatible with SPI and MICROWIRE™ protocols.