Bav99/ESD Interference or discharge damage circuit/interface Protection Circuit

Bav99/ESD Interference or discharge damage circuit/interface Protection Circuit

Bav99 is designed for the purpose of ESD. It is afraid that the signal line is vulnerable to ESD Interference or discharge damage the circuit. Because these interfaces are interconnected with each other, it is afraid that the received signal has large static electricity.

When several kV static electricity is input from the input end, the diode is reverse-Penetrated, and the charge is rapidly dropped to the ground or power supply. Most of the positive static electricity is put into the power supply, and most of the negative static electricity is put to the ground. Achieve the purpose of ESD protection.

When positive static electricity occurs, D2 works but D1 does not, so the clamp voltage (clamping voltage) is the forward voltage of 5 V plus D2.

When negative static electricity occurs, D1 works but D2 does not, so this clamp voltage is the forward voltage of D1.

It can also be changed to the following form, which is easier to understand:

Purpose:

1. Limit

2. Protection)

3. If it is placed next to the IC, it will prevent high-voltage power supply and negative pulse.

4. If it is placed in the interface circuit part, it is to suppress the conduction anti-disturbance. When the common mode interference of the interface circuit is coupled, a bidirectional high voltage is generated on the signal line. When bav99 is used, the voltage range is clamped at the interface. However, with external interference, the power supply for Positive Pressure clamping will generate large noise. Likewise, a negative pressure Clamp will produce a large amount of noise on the ground. Therefore, we recommend that you use bav99 together with the interface anti-volume filtering.

Instance

Assume that: VDD = 3.3 V, D1 and D2 are conduction voltage 0.6 V, and input signal voltage is V

If the conduction voltage of V> VDD + d1 is 3.9 V, d1 is turned on, and more current enters VDD, so that the signal voltage inside is <= 3.9 V;

If: v <vgnd = 0 V, D2 is turned on, and more than the current enters Gnd, so that the signal voltage entering the interior is about-0.6v;

Bav99/ESD Interference or discharge damage circuit/interface Protection Circuit