Surge protection against 10,000A on an 8/20 µsec waveform

April 18, 2014 // By Julien Happich
Bourns has added the Model 1840 surge protective device (SPD) for signal and data line applications, a heavy-duty, multi-stage protector designed to safeguard sensitive electronic circuits and components from damaging surge voltages and currents.

The new model features extremely fast response and low clamping voltages making it ideal for protection of signal and data lines associated with computer, data communication, instrumentation, broadcasting and industrial controls. The Bourns Model 1840 supports working voltages of 5, 12 and 24V, and may be used directly with RS-232, RS-422, RS-423 and RS-485 standard EIA interfaces as well as with 4-20 mA and 50 mA instrumentation loops.

Bourns’ solid-state, third stage protection device works by intercepting the leading edge of a surge within a sub-nanosecond response time. Within micro-seconds thereafter, a primary stage, three-electrode common-chambered Gas Discharge Tube (GDT) activates and crowbars the majority of the surge energy to ground.

The new model also uses Bourns' TBU High-Speed Protector (HSP) technology as a key second stage. Currents exceeding 300 mA through the protector will cause the TBU HSP to quickly transition into high impedance, isolating any harmful voltages and/or currents and prventing them from damaging the protected equipment. The GDT protector remains in the crowbar state until the surge has passed and line voltages return to safe levels. After an event, the TBU HSP automatically restores the line to normal operation by automatically resetting to a low impedance state.