CIRCUIT AND METHOD FOR LOW POWER CHIP ENABLE CIRCUITRY

A novel low power enable circuit is less sensitive to power supply variations while consuming less than 50 nA of supply current. The enable circuit includes a voltage clamp circuit which limits the supply level for a first inverter. The clamp circuit having a first input connected to a supply, a second input connected to chip enable, and a first output. The enable circuit further includes a first inverter having a third input connected to the chip enable, a fourth input connected to the first output of the clamp circuit, and a second output; a second inverter having a fifth input connected to the second output of the first inverter, a sixth input connected to the supply, and a third output; a memory element having a seventh input connected to the third output of the second inverter, an eighth input, and a fourth output; and a comparator having a ninth input connected to the chip enable, a tenth input connected to a reference signal, an eleventh input connected to the fourth output of the memory element, and a fifth output connected to the eighth input of the memory element.