24-Bit 8-/16-Channel ΔΣ ADC with Easy Drive Input Current Cancellation

The LTC2498 is a 16-channel (8-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 LTC2498 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 LTC2498 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 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.

Applications

* Direct Sensor Digitizer

* Direct Temperature Measurement

* Instrumentation

* Industrial Process Control

* Up to 8 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

* 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 (15Hz Using Internal Oscillator)

* 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 QFN 5mm × 7mm Package