24-Bit No Latency ∆Σ ADC with Differential Input and Reference in MSOP

The LTC2411/LTC2411-1 are 2.7V to 5.5V micropower 24-bit differential ∆Σ analog-to-digital converters with an integrated oscillator, 2ppm INL and 0.29ppm RMS noise. They use delta-sigma technology and provide single cycle settling time for multiplexed applications. Through a single pin, the LTC2411 can be configured for better than 110dB differential mode rejection at 50Hz or 60Hz ±2%, and the LTC2411-1 can provide better than 87dB input differential mode rejection over the range of 49Hz to 61.2Hz, or they can be driven by an external oscillator for a user-defined rejection frequency. The LTC2411 and LTC2411-1 are identical when driven by an external oscillator. 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 full-scale 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 the GND to VCC range of the LTC2411/LTC2411-1. The DC common mode input rejection is better than 140dB.

The LTC2411/LTC2411-1 communicate through a flexible 3-wire digital interface that is compatible with SPI and MICROWIRE protocols.

Applications

* Direct Sensor Digitizer

* Weight Scales

* Direct Temperature Measurement

* Gas Analyzers

* Strain Gauge Transducers

* Instrumentation

* Data Acquisition

* Industrial Process Control

* 6-Digit DVMs

* 24-Bit ADC in an MS10 Package

* Low Supply Current (200µA in Conversion Mode and 4µA in Autosleep Mode)

* Differential Input and Differential Reference with GND to VCC Common Mode Range

* 2ppm INL, No Missing Codes

* 4ppm Full-Scale Error and 1ppm Offset

* 0.29ppm Noise

* 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, Pin Selectable 50Hz/60Hz Notch Filter (LTC2411)

* Simultaneous 50Hz/60Hz Rejection (LTC2411-1)