Fast CMOS Amplifiers for High-Frequency Switched-Capacitor Circuits

A new approach for the optimization of high-speed amplifiers dedicated to SC integrators is presented. Inverter-based pseudo-differential structures are shown to be well-suited to high speed applications. The problem of their inherently poor PSRR is solved by an on-chip low-area voltage regulator. An algorithmic method developed for the computer-aided synthesis of the amplifier is described. Experimental results are presented for a SC filter with a 5MHz cut-off frequency at 50 Mhz sampling. PSSR performance and validity of the automatic dimensioning are finally discussed.