WEAK INVERSION CHARGE INJECTION IN ANALOG MOS SWITCHES

Abstract

The on chip test circuit for examining the charge injection in analog MOS switches has been described in detail, and has been fabricated and characterized. Mixed-mode circuit and device simulations have been performed, creating excellent agreements not only with the experimental waveforms but also with the measured switch-induced error voltage, Further investigation of the experimental and simulated results has separated the charge injection into three distinct components: i) the channel charges in strong inversion; ii) the channel charges in weak inversion; and iii) the charges coupled through the gate-to-diffusion overlap capacitance, Important observations concerning the weak inversion charge injection have been drawn from the waveform of the current through the switched capacitor, In this work the channel charges in weak inversion have exhibited a 20% contribution to the switch-induced error voltage on a switched capacitor.