Rejection circuitry for variable-gain amplifiers and continuous-time filters

摘要

Variable-gain amplifiers (VGAs) and/or continuous-time filters (CTFS) are implemented with circuitry that provides improved power-supply rejection. The power-supply rejection circuitry may include a current source and a diode-connected MOSFET that inhibit noise in the reference-voltage power supply from reaching the output nodes of the VGA or CTF. Although the present invention enables separate implementations of VGAs and CTFs, in one embodiment, a VGA function and a CTF function are implemented in a single set of (e.g., integrated) circuitry.