16-bit, 5 Msps SAR ADC has wide input common mode range

May 25, 2016 // By Graham Prophet
LTC2311-16 is a 16-bit, 5 Msample/sec successive approximation register (SAR) analogue-to-digital converter (ADC) with a wide rail-to-rail input common mode range, that features a flexible differential input accepting analogue signals up to the Nyquist frequency.

This ADC provides direct conversion of a variety of signal types while maintaining signal-to-noise ratio (SNR) of 81.6 dB with a 2.2 MHz input signal, and achieving a high common mode rejection ratio (CMRR) of 85 dB for the same high speed input signal.


Instrumentation and medical applications that require channel-to-channel isolation often use single-channel ADCs to individually isolate front-end circuitry. Each of the ADC channels 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 impacts the complexity of the system. The flexible differential inputs and wide input common mode range of the LTC2311-16 simplify the input signal conditioning design.


The LTC2311-16 leads a pin-compatible family of 16-, 14- and 12-bit SAR ADCs with sample rates of 5 Msps and 2 Msps. These devices integrate a precision internal reference with low drift, guaranteeing 20 ppm/°C maximum temperature coefficient. This family can be powered from either a 3.3V or 5V supply, and consumes 30 mW with a 3.3V supply and 50 mW at 5V. The high speed SPI-compatible CMOS or LVDS serial interface is suitable for highly integrated high speed systems. In commercial, industrial and automotive (-40°C to 125°C) temperature grades, pricing begins at $9.95 (1000).


Linear Technology; www.linear.com/product/LTC2311-16