How to Improve the Efficiency of TVS Application in Circuits

How to Improve the Efficiency of TVS Application in Circuits

How to improve the effectiveness of TVS application in circuits? The wiring of printed circuit boards and the selection of circuit components are very important. By placing TVS in a reasonable position, grounding selection, parasitic inductance, and circuit area treatment, PCB wiring and TVS diode selection are scientifically and reasonably carried out to maximize the effectiveness of TVS.

PCB Layout Guidelines

position

TVS devices should be used on all data and power lines located on I/O connectors entering and exiting the PCB. Make the TVS device as close as possible to the noise source to ensure that the surge voltage can be clamped before the pulse is coupled to adjacent PCB wires. In addition, PCBs should use shorter TVS wires to reduce the consumption of surge energy. Placing sensitive wires in the center can avoid ESD during processing.

Grounding selection

If possible, the protection circuit shall shunt the surge voltage to the reference or case ground, and Ground bounce will be caused if the surge voltage is directly shunted to the signal ground of the integrated circuit. Reducing impedance with relatively short and wide grounding wires can improve the clamping performance of TVS diodes on a single grounded PCB.

Parasitic inductance

The parasitic inductance of PCB layout and Integrated circuit packaging will cause obvious overshoot of TVS clamping voltage. Using short wires and multiple layers of discrete ground and power boards can reduce the inductance of PCBs. Choosing a small surface mount can reduce the inductance of the package.

Loop area

Reducing the loop area formed by high-speed data and grounding wires can reduce the impact of radiation and radio frequency. Especially when the wires are long, an effective way to alleviate the loop problem is to include a grounding plate in the PCB design, increase the TVS transistor, and provide isolation for the separation interval between integrated circuits. But it will increase the loop area.