Aspects of the invention provide for an electrostatic discharge (ESD) clamp. In one embodiment, the ESD clamp includes: a silicon controlled rectifier (SCR); and a trigger circuit for providing a tunable trigger voltage to turn on the SCR, the trigger circuit including a metal-insulator transition (MIT) material. The trigger circuit includes an MIT resistor that includes a width and a length that tunes the trigger voltage to a desired voltage.