Abstract: An output buffer includes a pair of P-channel transistors and two cascode pull-down N-channel transistors to drive an output node. The output pull-up transistor has the gate thereof connected through a P-channel control transistor to an input driving signal. The control signal is isolated from the output node by a P-channel transistor which only conducts during overvoltage conditions. During normal operation, the control transistor is maintained in a conductive state to allow the gate of the output pull-up transistor to be pulled high and low. During an overvoltage condition, the P-channel transistor connected between the output node and the control transistor is turned on in order to effectively turn off the control transistor. The P-channel transistors in the output buffer are floating well-type transistors with the wells thereof tied to a switched voltage that is either the supply voltage during the normal operating mode or the output node during overvoltage conditions.