Systems and methods are provided for fail-safe protection of circuitry from electrostatic discharge due through input and output connections. The power circuitry may include a string of diodes, connections to power lines, and particular diodes for voltage pull-up and pull-down clamping. There may be both a pull-up third diode in the diode string for connection between I/O and VDD and a pull-down third diode between I/O and VSS. During an ESD event the ESD device is configured to hold voltage from exceeding a threshold voltage and damaging internal circuitry. During operational mode the ESD device is turned off and does not interfere with circuit operations.