Shanghai Leiditech often received help from customers: "My circuit added ESD diode, and it is a big brand, why static electricity still does not pass, causing the back-end chip to burn", "crash", "How to do this, you help me think of a way" and so on. EMC brother made an analysis and judgment in view of this situation:

1, may be the back-end IC withstand voltage is relatively low. Need to be replaced with a high voltage IC.

2, may be ESD diode clamping voltage is too high caused. Therefore, a low clamping voltage ESD diode is needed to ensure that the clamping voltage of the diode is lower than the maximum voltage of the protected device.

The engineer will reply: "The back-end chip has been determined, there is no way to change, and I can't find a low VC (low clamp voltage) ESD diode."

This situation is indeed more common, subject to various conditions, the back-end IC can not be changed. Shanghai Lemao EMC small brother according to customer demands, launched the following low VC ESD diodes, the list is as follows.

The above table is a list of products that are often used with high operating voltage but low clamping voltage VC. It can be seen from the table that under the same VRWM condition, ESD of leiditech products has a much lower VC than NXP and PANJIT. This can help engineers solve the problem of burning out the above IC. The relationship between VC and IPP of one SMC24LV in the above table is shown below.

As can be seen from the figure above, Vc does not change much as IPP increases.

If engineers are using the low-voltage ESD series, please refer to the previous article published here. Back sweep function ESD and TVS benefits - Electronics enthusiast network

For ESD diode selection EMC brother share selection method:

First, select Vrwm voltage: higher than the highest operating voltage of the circuit.

Second, select the breakdown voltage: it should be higher than the normal working voltage of the circuit, and consider the voltage fluctuations that may occur in the circuit, generally leaving a certain margin.

Third, clamping voltage: it should be lower than the maximum voltage of the protected device to ensure that the device can be effectively protected in overvoltage situations such as electrostatic discharge, such as the maximum voltage of the protected device is 15V, should choose ESD diodes with clamping voltage lower than 15V.

Fourth, the peak pulse current: the peak pulse current of the selected ESD diode is greater than the maximum electrostatic discharge current that may occur.

Fifth, junction capacitance: for high-frequency signal circuits, the junction capacitance should be low enough to ensure that the signal transmission quality is not affected.

Leiditech is committed to becoming a leading brand in the supply of electromagnetic compatibility solutions and components, supplying ESD, TVS, TSS, GDT, MOV, MOSFET, Zener, inductors and other products. Lei MAO has an experienced R & D team, can provide personalized customized services according to customer needs, to provide customers with the best quality solutions.