A/D converter cuts system complexity

A 16bit 5Msample/s successive approximation register (SAR) A/D converter from Linear Technology has a wide rail to rail input common mode range.

The LTC2311-16 features a flexible differential input that accepts analogue signals up to the Nyquist frequency. This provides direct conversion of a variety of signals while maintaining a signal to noise ratio of 81.6dB with a 2.2MHz input signal. The company adds the device offers a common mode rejection ratio of 85dB for the same input signal.

Instrumentation and medical applications that require channel to channel isolation often use single channel A/D converters to isolate front end circuitry. Each converter channel then requires its own signal conditioning circuitry, along with an isolated power source. This circuit is replicated on all channels, so any simplification in the circuit has an effect on system complexity. The flexible differential inputs and wide input common mode range of the LTC2311-16 are said to simplify the input signal conditioning design, reducing component count, system cost, power consumption and board space.

The LTC2311-16, which can be powered from a 3.3V or 5V supply, consumes 30mW or 50mW respectively and is available in commercial, industrial and automotive temperature grades