Reasons for short-circuit failure of bidirectional TVS tube SMBJ30CA

TANGHONGXI

Reasons for short-circuit failure of bidirectional TVS tube SMBJ30CA [Copy link]

 

The TVS is placed next to the connector, the voltage is 24V, and the maximum current of the circuit is 10A. Now the TVS is short-circuited and failed, and the fuse is blown. I would like to ask what may be the cause.

maychang

The failure of TVS tubes is usually caused by long duration of overvoltage. TVS tubes can only work in a very short time. Although the power is quite large in a short time, it can only consume very little energy.

PowerAnts

When developing, you must learn to find answers from the specification

qwqwqw2088

It is recommended to use a TVS tube with higher power or add an overvoltage protection circuit. Generally, the TVS tube is broken because the surge voltage and current exceed the rated specification requirements of the TVS tube.

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Or the instantaneous high voltage is too high, the instantaneous voltage exceeds the normal working voltage of the circuit, or there is a large current impact, which requires a good test before judgment. Everyone's analysis of the reasons should be linked to their own tests.

qwqwqw2088

Or the instantaneous high voltage is too high, the instantaneous voltage exceeds the normal working voltage of the circuit, or there is a large current impact, which requires a good test before judgment. Everyone's analysis of the reasons should be linked to their own tests.

langtuodianzi

The transient high voltage or long-lasting overcurrent flowing through the TVS tube causes damage. The pulse power of the TVS tube is related not only to the peak pulse current and clamping voltage, but also to the pulse waveform, pulse duration and ambient temperature. Reasonable derating design should be considered when applying.

涛子W1

I'll help you test it and then change the plan

langtuodianzi

Fuses or PTCs can be used in short circuit and overload current situations. If the surge current is too large, a gas discharge tube GDT or varistor, or a higher power diode (such as 1500W) BV-SMCJ30CA can be used.

qwqwqw2088

langtuodianzi posted on 2018-11-16 15:01 Fuses or PTCs can be used in short circuit and overload current situations. If the surge current is too large, gas discharge tubes GDT or varistors, or more powerful ones, can be used...

If the surge current is too large, TVS is more suitable. Gas discharge tubes are not suitable here and react slowly.

langtuodianzi

The reasons caused by component quality also need to be considered. Many TVS diodes on the market are of poor quality, and some are even counterfeit!

bestican

Most likely the voltage is unstable. It is recommended to increase the TVS voltage.

luck_gfb

It is best to put on the schematic diagram, everyone can help analyze

东沃电子

You can consult a professional passive protection device supplier. Generally, they have professional electronic engineers.