Features

• Pin Compatible 4-/8-Channel 24-Bit ADCs
• Single Conversion Digital Filter Settling Time Simplifies Multiplexing
• 4ppm INL, No Missing Codes
• 4ppm Full-Scale Error
• 0.5ppm Offset
• 0.3ppm Noise
• Internal Oscillator—No External Components Required
• 110dB Min, 50Hz/60Hz Notch Filter
• Reference Input Voltage: 0.1V to VCC
• 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

Typical Application

Description

The LTC2404/LTC2408 are 4-/8-channel 2.7V to 5.5V micropower 24-bit A/D converters with an integrated oscillator, 4ppm INL and 0.3ppm RMS noise. They use delta-sigma technology and provide single cycle digital filter settling time (no latency delay) for multiplexed applications. The first conversion after the channel is changed is always valid. Through a single pin the LTC2404/LTC2408 can be configured for better than 110dB rejection at 50Hz or 60Hz ±2%, or can be driven by an external oscillator for a user defined rejection frequency in the range 1Hz to 120Hz. The internal oscillator requires no external frequency setting components. The converters accept any external reference voltage from 0.1V to V_CC. With their extended input conversion range of –12.5% V_REF to 112.5% V_REF the LTC2404/LTC2408 smoothly resolve the offset and overrange problems of preceding sensors or signal conditioning circuits. The LTC2404/LTC2408 communicate through a flexible 4-wire digital interface which is compatible with SPI and MICROWIRE protocols.