CMOS front-end amplifier for broadband DTV tuner

摘要

In this work, the design of a CMOS broadband low noise amplifier with inherent highperformance single-to-differential conversion is presented. These characteristics aredriven by the double quadrature single conversion digital television tuner which requiresaccurately balanced differential signals to perform its function and to improve imagerejection.A three-stage amplifier is designed to satisfy several requirements of front-end circuits atthe same time. The resistive shunt-feedback topology is adopted to implement asingle-ended broadband low-noise amplifier as the first stage. The second stage is anon-chip single-to-differential converter, which employs a novel method to improve itsbalancing performance. A fully differential buffer capable of driving heavy loads is usedas the third stage to further suppress the phase and magnitude errors of outputdifferential signals.Fabricated in 0.35??m TSMC standard CMOS technology, the designed broadbandfront-end amplifier manages to limit the phase error to within ??1.5?? and magnitude error??0.75dB over 50~850 MHz frequency range, with 16dB gain and a noise figure of 4dB.