Fundamental blocks of single ended LVCMOS output buffer- a circuit level design guideline

Abstract

IO buffers serve in interfacing core circuits in a system on chip and signals originating in the core to external world devices. LVCMOS standard buffers are general purpose IOs providing the single ended interface. In deep sub-micron technology nodes such as the 65 nm and beyond, issues such as short channel effects, hot carrier effect, NBTI, gate oxide integrity, leakage dominance and the like are proving hard to combat. This lecture presentation describes the fundamental blocks in an LVCMOS IO buffer and addresses the various issues arising in IO circuits, explains basic design approach for transmitter and receivers of an LVCMOS IO and suggests alternate design solutions to reduce the effect of the performance and reliability threats.