SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

In a CMOS integrated circuit certain high-impedance nodes are particularly susceptible to noise signals from the power supply. The power supply noise rejection is improved by using transistors 72, 74 of one type only, which are formed in tubs, such as N-channel transistors formed in P-type tubs in an N-type substrate, for connection to the critical high-impedance nodes 76. The tubs of these transistors are preferably connected (via 70) to an on-chip regulated power supply 66, 68. Noise rejection is further improved by grounded tubs underlying any conductive runners 80, 82 and capacitors 84 connected to the critical nodes 76.