24-Bit 2-/4-Channel ΔΣ ADC with Easy Drive Input Current Cancellation

The LTC2492 is a 4-channel (2-channel differential), 24-bit, No Latency ΔΣ™ ADC with Easy Drive technology. 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 LTC2492 includes a high accuracy temperature sensor and an integrated oscillator. This device can be configured to measure an external signal (from combinations of 4 analog input channels operating in single-ended or differential modes) or its internal temperature sensor. It can be programmed to reject line frequencies of 50Hz, 60Hz, or simultaneous 50Hz/60Hz and configured to double its output rate. The integrated temperature sensor offers 1/30th°C resolution and 2°C absolute accuracy.

The LTC2492 allows a wide common mode input range (0V to VCC), independent of the reference voltage. Any combination of single-ended or differential inputs can be selected and the first conversion after a new channel selection is valid.

Applications

* Direct Sensor Digitizer

* Direct Temperature Measurement

* Instrumentation

* Industrial Process Control

* Up to 2 Differential or 4 Single-Ended Inputs

* Easy Drive™ Technology Enables Rail-to-Rail Inputs with Zero Differential Input Current

* Directly Digitizes High Impedance Sensors with Full Accuracy

* 600nVRMS Noise

* Integrated High Accuracy Temperature Sensor

* GND to VCC 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 Mode/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 DFN 4mm × 3mm Package