Leakage currents at IC inputs can be avoided while the IC is disabled by providing a switch that is responsive to deactivation of an enable input to isolate functional circuitry of the IC from one of the power supply nodes of the IC. This eliminates power supply current while the IC is disabled. Further unwanted current flow can be avoided while the IC is disabled by providing a switch that is responsive to the enable input for selectively connecting and disconnecting the base of a reference voltage transistor to and from the transistor's grounded collector, which collector is defined by the substrate of the IC. Disconnection of the base from the grounded substrate/collector eliminates base current and thus prevents emitter-to-collector current flow through the transistor when the IC is disabled.
Leakage current at the inputs of an integrated circuit can be reduced by providing a master/slave arrangement wherein a plurality of slave inputs are controlled by an enable input acting as a master. When the enable input is deactivated, the slave inputs break their leakage current paths. An input structure with improved hysteresis can be provided by coupling a follow-on inverter to the output of the input stage, and coupling a hysteresis feedback circuit to the output of the follow-on inverter. The hysteresis feedback circuit is also connected to a node of the input stage other than the output thereof.
