Low-noise amps designed to drive SAR ADCs
Three variants of Analog Devices’ LTC6363 fully differential, low-noise amplifier provide fixed gains of 0.5 V/V, 1 V/V, and 2 V/V. While the LTC6363 offers user-settable gain using four external resistors, the LTC6363-0.5, LTC6363-1, and LTC6363-2 fixed-gain amplifiers have internal laser-trimmed resistors, affording both precision and a compact footprint. All four devices furnish differential rail-to-rail outputs for driving 20-bit, 18-bit, and 16-bit SAR ADCs.
The LTC6363 series provides initial gain accuracy of 45 ppm maximum, which varies by just 0.5 ppm/°C maximum over temperature. Common-mode rejection ratio, typically limited by discrete resistor matching, is 94 dB minimum—equivalent to 0.002% resistor matching. Each device in the amplifier family operates with supply voltages from 2.8 V (±1.4 V) to 11 V (±5.5 V) and draws a supply current of only 1.75 mA typical.
>> Continue reading this article on our sister site, EDN: "Low-power amps drive SAR ADCs."