LT6600-20 - Very Low Noise, Differential Amplifier and 20MHz Lowpass Filter

The LT®6600-20 combines a fully differential amplifi er with a 4th order 20MHz lowpass fi lter approximating a Chebyshev frequency response. Most differential amplifi ers require many precision external components to tailor gain and bandwidth. In contrast, with the LT6600-20, two external resistors program differential gain, and the fi lter’s 20MHz cutoff frequency and passband ripple are internally set. The LT6600-20 also provides the necessary level shifting to set its output common mode voltage to accommodate the reference voltage requirements of A/Ds. Using a proprietary internal architecture, the LT6600-20 integrates an antialiasing fi lter and a differential amplifi er/driver without compromising distortion or low noise performance. At unity gain the measured in band signalto-noise ratio is an impressive 76dB. At higher gains the input referred noise decreases so the part can process smaller input differential signals without signifi cantly degrading the output signal-to-noise ratio. The LT6600-20 also features low voltage operation. The differential design provides outstanding performance for a 2VP-P signal level while the part operates with a single 3V supply. The LT6600-20 is packaged in an SO-8 and is pin compatible with stand alone differential amplifi ers.