New Industry Products

New Bourns Circuit Protection Series Features Broad Range of Trigger Currents & Voltages

September 06, 2010 by Jeff Shepard

Bourns, Inc. announced the company’s next-generation Transient Blocking Unit (TBU™) Series of circuit protection devices designed to protect a broad selection of industrial and telecommunications applications. The new series provides ultra-fast overcurrent protection offered in a wide range of trigger currents and voltages and reduced form factors to save valuable board space. Designated the Bourns® TBU-CA Series, the new devices are electronic current limiters (ECL) that are triggered by excessive voltage or current. Designed as an optimal circuit protection solution for industrial controls, medical electronics, automated test systems, and military and aerospace applications, the Bourns TBU-CA Series can be used for protection on Ethernet, RS-485, HART and other ports where dangerous surge and power cross events may occur. The circuit protection device series can also be used in telecom applications and provides a barrier to surges while allowing high frequency signals such as VDSL2 to pass through without damage to the circuit.

Protecting sensitive electronics and applications from the potentially damaging effects of surges that can cause current and voltage to rise above normal operating levels, the Bourns TBU-CA Series eliminates the need for large shunt protection devices by stopping the damaging currents from reaching protected circuits in less than one microsecond. The new circuit protection devices are low capacitance, single bidirectional high speed devices designed to protect against faults caused by short circuits, ac power cross, induction and lightning surges within rated limits. The resettable devices also feature significantly lower let-thru energy and overshoot protection, which reduces stress on the printed circuit board (PCB) for increased reliability and product life.

"Higher data rates combined with more sensitive electronics presents a real challenge for protection engineers," said Paul Wiener, Telecom Market Director at Bourns. "Bourns’ unique TBU protection technology limits the energy allowed into sensitive electronics without loading high data rate lines with capacitance. This allows designers to place high performance protection on even their highest bandwidth applications."

The Bourns TBU-CA Series is available in five impulse blocking voltages from 250 to 850V with minimum trip currents of 50 to 500mA featuring resistance values as low as 3Ω. Product samples, evaluation boards and sample kits are available now through Bourns’ distribution partners. As a pricing example, Bourns TBU-CA085-500-WH is priced at ($.69 each) in (10K) quantities.

Bourns states that its TBU High Speed Protector is the first new approach to electronics circuit protection in over a decade. This technology is designed to block a transient through a current disconnecting mechanism. Rather than a complex interstage coordination between two shunting components, the TBU device allows customers to protect circuit boards from both overvoltage and overcurrent surges. The TBU device protects electronic equipment within nanoseconds, essentially eliminating latency common in the circuit protection design, limiting let-through energy. The TBU device has virtually no capacitance or inductance, and therefore can be used in high bandwidth applications. It has a resistive characteristic which permits currents up to a certain level to pass unimpeded to the protected interface. In higher current situations, the TBU device switches to a high impedance state, protecting until the surge voltage dissipates or the short-circuit reseals. The TBU device offers full bi-directional operation, which is inherently resettable.