Patent ID: 8558603

Claim:
An apparatus comprising: a level shifter circuit coupled between a first input node in a first voltage domain and an output node in a second voltage domain, wherein the level shifter circuit is configured to receive a first input signal on the first input node, wherein the level shifter is configured to drive an output signal corresponding to the first input signal on the output node responsive to a first state of a select signal; a first pull-up transistor configured to pull the output node up to an operating voltage of the second voltage domain responsive to a second state of the select signal and a first state of a second input signal; a pull-down transistor configured to pull the output node down to a ground voltage responsive to a second state of the select signal and a second state of the second input signal; and isolation circuitry coupled to receive an isolation signal, wherein the isolation circuitry is configured to inhibit the level shifter circuit from driving the output node when the isolation signal is asserted.