What are the applications of TVS diodes?

Last Update Time: 2021-07-09 10:48:30

It has been widely used in computer systems, communication equipment, AC / DC power supplies, automobiles, electronic ballasts, household appliances, instrumentation (electric meters), RS232 / 422/423/485, I / O, LAN, ISDN, ADSL, USB, MP3, PDAS, GPS, CDMA, GSM, digital camera protection, common mode / differential mode protection, RF coupling / IC drive receiving protection, motor electromagnetic interference suppression, audio / video input, sensor / transmission, industrial control loop , Relays, contactor noise suppression and other fields. The main electrical parameters of TVS devices

(1) Breakdown voltage V (BR)

In the area where the device breaks down, under the specified test current I (BR), the voltage measured across the device is called the breakdown voltage. In this area, the diode becomes a low-impedance path.

(2) Maximum reverse pulse peak current IPP

In reverse operation, under the specified pulse conditions, the maximum pulse peak current allowed by the device. The product of IPP and the maximum clamping voltage VC (MAX) is the maximum value of the transient pulse power.

When using it, the TVS should be selected correctly so that the rated transient pulse power PPR is greater than the maximum transient surge power that may be generated by the protected device or line.

Classification of TVS diodes

TVS devices can be divided into unipolar and bipolar according to polarity, and can be divided into general-purpose devices suitable for various circuits and special-purpose devices suitable for special circuits according to their uses. Such as: various AC voltage protectors, 4 ~ 200mA current environmental protectors, data line protectors, coaxial cable protectors, telephone protectors, etc. According to the package and internal structure, it can be divided into: axial lead diode, dual in-line TVS array (for multi-line protection), patch type, component type and high power module type.

Features of TVS diodes

(1) Adding TVS diodes to the signal and power lines can prevent microprocessors or single-chip microcomputers from malfunctions caused by instantaneous fat flushes, such as electrostatic discharge effects, AC power surges and switching power supply noise.

(2) The electrostatic discharge effect can release pulses exceeding 10000V and 60A, and can last for 10ms; while a general TTL device encounters a 10V pulse exceeding 30ms, it will lead to damage. The use of TVS diodes can effectively absorb pulses that can cause damage to the device, and can eliminate interference caused by switching between buses (Crosstalk).

(3) Place the TVS diode between the signal line and the ground to avoid unnecessary noise from the data and control bus.

Selection tips for TVS

(1) Determine the maximum DC or continuous working voltage of the protected circuit, the rated standard voltage of the circuit and the "high-end" tolerance.

(2) TVS rated reverse turn-off VWM should be greater than or equal to the maximum working voltage of the protected circuit. If the selected VWM is too low, the device may enter an avalanche or affect the normal operation of the circuit due to excessive reverse leakage current. The serial connection divides the voltage, and the parallel connection divides the current.

(3) The maximum clamping voltage VC of TVS should be less than the damaged voltage of the protected circuit.

(4) Within the prescribed pulse duration, the maximum peak pulse power consumption PM of the TVS must be greater than the peak pulse power that may appear in the protected circuit. After the maximum clamping voltage is determined, its peak pulse current should be greater than the transient surge current.

(5) For the protection of the data interface circuit, we must also pay attention to the selection of TVS devices with appropriate capacitance C.

(6) Select the polarity and packaging structure of TVS according to the application. It is more reasonable to choose bipolar TVS for AC circuit; it is more advantageous to choose TVS array for multi-line protection.

 

If you want to know more, our website has product specifications for diode, you can go to ALLICDATA ELECTRONICS LIMITED to get more information