Convertor takes temperature onboard

Linear Technology has introduced the LTC2492, a four-channel delta-sigma analogue-to-digital convertor (ADC) that integrates a temperature sensor and a novel front-end design in a tiny 4 x 3mm DFN package.

The LTC2492's Easy Drive design results in zero average differential input current, allowing measurements of high impedance input sources without the need for an internal buffer.

This patented sampling scheme simplifies the design of front-end signal conditioning circuits and allows the ADC to be driven directly from bridges, RTDs, thermocouples and high impedance sensors.

Rail-to-rail input signals can be directly digitised while maintaining excellent DC accuracy (2ppm INL).

The LTC2492 includes a high accuracy internal temperature sensor that offers 1/30degC resolution and 2C absolute accuracy.

The ADC converts the output of the temperature sensor or the input multiplexer, which can be configured for four single-ended channels, two differential channels, or two single-ended and one differential.

After a new channel is selected, the LTC2492's No Latency Delta-Sigma digital filter settles in a single cycle.

The LTC2492 communicates via a four-wire SPI-compatible serial interface and performs conversions at rates of 15Hz or 7.5Hz while using the internal oscillator.

The LTC2492 can be configured to reject line frequencies of 50 or 60Hz or simultaneous 50/60Hz, while maintaining 600nV RMS noise across the full input voltage range.

For lower resolution applications, Linear Technology is also introducing the LTC2488, a pin-compatible 16bit ADC.

The LTC2492 and LTC2488 are each available in DFN-14 (4 x 3mm) packages, offering a pin-compatible and code-compatible family for performance/cost optimisation.

Both Easy Drive delta-sigma ADCs are available in commercial and industrial temperature ranges.

Pricing begins at US $2.95 each for the LTC2492 and $2.15 each for the LTC2488, in 1000-piece quantities.