16-bit, 5MS/s SAR ADC simplifies AFE circuitry

25th May 2016

Nat Bowers

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Datasheet

A 16-bit, 5MS/s SAR (Successive Approximation Register) ADC with a wide rail-to-rail input common mode range, the LTC2311-16, has been introduced by Linear Technology. 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 signal types while maintaining a good SNR of 81.6dB with a 2.2MHz input signal and achieving a high CMRR of 85dB 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 has a profound effect on 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, significantly lowering the required component count, reducing system cost, power consumption and circuit board space.

The LTC2311-16 leads a pin-compatible family of 16-, 14- and 12-bit SAR ADCs with sample rates of 5 and 2MS/s. These devices integrate a precision internal reference with low drift, guaranteeing 20ppm/°C maximum temperature coefficient to simplify system design. This family can be powered from either a 3.3 or 5V supply, consuming 30mW with a 3.3V supply and 50mW at 5V. The high speed SPI-compatible CMOS or LVDS serial interface is suited for highly integrated high speed systems.

The LTC2311-16 is available now in commercial, industrial and automotive (-40 to +125°C) temperature grades. Other devices in the family will be released during 2016. Pricing begins at $9.95 each in 1,000 unit quantities.