An integrated circuit I/O buffer has an output driver. The output driver includes first, second and third voltage supply terminals and a pad terminal. A pad pull-up transistor is coupled in series between the first voltage supply terminal and the pad terminal and has a pull-up control terminal. A pad pull-down transistor is coupled in series between the second voltage supply terminal and the pad terminal and has a pull-down control terminal. A voltage protection transistor is coupled between the pad terminal and the pad pull-down transistor. The voltage protection transistor has a control terminal and a capacitance between the control terminal and the pad terminal. A resistor is coupled in series between the control terminal of the voltage protection transistor and the third voltage supply terminal and forms a resistor-capacitor (RC) circuit with the capacitance.