Precautions for using transient diodes

The relationship between the absorption power (peak value) of transient voltage and the pulse width of transient voltage. The manual only provides the absorption power (peak value) at a specific pulse width, while the pulse width in actual circuits can vary unpredictably and needs to be estimated in advance. The wide pulse should be downgraded for use.

For the protection of low current loads, it is possible to consciously add current limiting resistors in the circuit. As long as the resistance of the current limiting resistor is appropriate, it will not affect the normal operation of the circuit, but the current generated by interference will be greatly reduced by the current limiting resistor. It is possible to use TVS diodes with lower peak power to protect low current load lines.

The suppression of repeated transient voltages, particularly noteworthy is whether the steady-state average power of the TVS diode is within a safe range.

Reduced usage

As a semiconductor device, TVS diodes should pay attention to the issue of derating when the ambient temperature rises. Special attention should be paid to the lead length of the TVS diode and its relative distance from the protected circuit. When there is no suitable voltage TVS diode available for use, it is allowed to use multiple TVS diodes in series. The maximum current of a series diode is determined by the diode with the smallest current absorption capacity used. And the peak absorption power is equal to the product of this current and the sum of the series diode voltage.

The junction capacitance of TVS diode is a key factor affecting its use in high-speed lines. In this case, a TVS diode is generally connected back-to-back with a fast recovery diode. Due to the small junction capacitance of the fast recovery diode, the equivalent capacitance of the two in series is also small, which can meet the requirements of high-frequency use.

Conclusion: Various electronic systems and communication networks are often subject to external electromagnetic interference, which mainly comes from transient processes of power lines, lightning strikes, and cosmic radio waves. These interferences can cause system errors and even hardware damage. For these issues, comprehensive preventive and protective measures should be taken, and designing and selecting suitable silicon transient absorption diodes is a good solution to solve transient interference. But as the electronics industry explores more electronic products that improve efficiency, increase functionality, and continuously improve integration, designing and providing complete circuit protection solutions will form another revolution in circuit protection technology.