WEE Technology Company Limited 

Manufacturer of Surface Mount (SMD) and Through Hole (DIP) Diodes & Rectifiers

Important parameters of TVs

A major challenge in automotive design is to protect automotive electronic equipment (such as control units, sensors and entertainment systems) from damaging surges, voltage transients, ESD and power line noise. The use of transient voltage suppressor (TVS) is an ideal solution to protect automotive electronic equipment. Next, we will discuss the key parameters of TVs devices - power level, off state voltage and maximum breakdown voltage.

Power level

The power level of TVs is the surge absorption capacity under specific test or application conditions. Vishay's TVs products use industry standard 10 / 1000 μ s pulse waveform

(Bellcore 1089 standard) as the test condition, as shown in Figure 1. This test condition is different from the 8 / 20 μ s pulse waveform of TVs ESD test

Breakdown voltage (VBR)

The breakdown voltage is the voltage at which the device enters the avalanche breakdown, which is tested according to the current specified in the data sheet.

Maximum breakdown voltage (VC: clamping voltage)

Clamping voltage level that appears on TVs at the specified peak pulse current level. The breakdown voltage of TVs is measured at very low current, such as 1 mA or 10 Ma, which is different from the actual avalanche voltage in application conditions. Therefore, semiconductor manufacturers will indicate typical or maximum breakdown voltage under high current conditions.

Off state voltage (VWM: working off state reverse voltage)

Off state voltage refers to the maximum voltage when TVs is not broken down. It is an important parameter of protection device which does not work under normal conditions. In automotive applications, the regulation of some automotive electronic products is realized by "step protection". This test condition is to supply 24 VDC to 12 V electronic equipment and 36 VDC to 24 V electronic equipment within 10 minutes without causing damage or circuit failure. Therefore, for automotive electronic products, off state voltage is a key parameter of TVs devices.