Very-low-voltage circuit surge protection

November 23, 2016 // By Graham Prophet
Bourns’ TISP low voltage bidirectional protectors are bidirectional devices that limit damaging overvoltage threats, providing 2-point protection for transformer windings, low voltage electronics and digital telecommunication lines.

Electrically, the devices are symmetrical voltage-triggered bidirectional thyristors. Overvoltages are initially clipped by breakdown clamping until the voltage rises to the breakover level, which causes the device to crowbar into a low-voltage on-state condition. This low-voltage on-state causes the current resulting from the overvoltage to be safely diverted through the device. The device switches off when the diverted current falls below the holding current value.


Model TISP4011H1BJ, as with other members of the Model TISP40xxH1BJ series, features very low V(bo) breakover voltage of 10.5V, which allows designers to protect lines of working voltages up to 5.25V, with low voltage overshoot and low capacitance. The TISP4011H1BJ is priced at $0.30 (12,000).