In a described example, an apparatus includes a driver circuit coupled to an output pad, the driver having a p-channel FET coupled between a positive peripheral voltage and the pad, and having a first gate terminal coupled to a first gate control signal, and an n-channel FET coupled between the pad and a ground terminal and having a second gate terminal coupled to a second gate control signal. A predriver circuit is coupled to receive a data signal for output to the pad and further coupled to output the first gate control signal; and the predriver circuit is coupled to output a supply voltage to the first gate control signal in a first mode, and to output a bias voltage less than the supply voltage to the first gate control signal in a second mode; and a bias circuit is coupled for outputting the bias voltage.