Features

• Up to Eight Differential or 16 Single-Ended Inputs
• Easy Drive™ Technology Enables Rail-to-Rail Inputs with Zero Differential Input Current
• Directly Digitizes High Impedance Sensors with Full Accuracy
• 2-Wire I²C Interface with 27 Addresses Plus One Global Address for Synchronization
• 600nV_RMS Noise
• Integrated High Accuracy Temperature Sensor
• GND to V_CC Input/Reference Common Mode Range
• Programmable 50Hz, 60Hz or Simultaneous 50Hz/60Hz Rejection Mode
• 2ppm INL, No Missing Codes
• 1ppm Offset and 15ppm Full-Scale Error
• 2x Speed/Reduced Power Mode (15Hz Using Internal Oscillator and 80μA at 7.5Hz Output)
• No Latency: Digital Filter Settles in a Single Cycle, Even After a New Channel Is Selected
• Single Supply 2.7V to 5.5V Operation (0.8mW)
• Internal Oscillator
• Tiny 5mm × 7mm QFN Package

Typical Application

Description

The LTC2499 is a 16-channel (eight differential), 24-bit, No Latency ΔΣ ADC with Easy Drive technology and a 2-wire, I²C interface. The patented sampling scheme eliminates dynamic input current errors and the shortcomings of on-chip buffering through automatic cancellation of differential input current. This allows large external source impedances and rail-to-rail input signals to be directly digitized while maintaining exceptional DC accuracy.

The LTC2499 includes a high accuracy, temperature sensor and an integrated oscillator. This device can be configured to measure an external signal (from combinations of 16 analog input channels operating in single- ended or differential modes) or its internal temperature sensor. The integrated temperature sensor offers 1/30th°C resolution and 2°C absolute accuracy.

The LTC2499 allows a wide common mode input range (0V to V_CC), independent of the reference voltage. Any combination of single-ended or differential inputs can be selected and the first conversion, after a new channel is selected, is valid. Access to the multiplexer output enables optional external amplifiers to be shared between all analog inputs and auto calibration continuously removes their associated offset and drift.