Contents
What is breakdown voltage of TVS diode?
The breakdown voltage (VBR) is the voltage where a TVS diode begins to conduct current, defined typically at 1 mA leakage. VBR defines the inflection point on the diode curve where the leakage beings to increase exponentially, which is typically referred as the diode ‘turning on’.
Is a diode a voltage limiting device?
Diodes are voltage limiting devices, which means they conduct just enough current to hold the voltage to the threshold level. However, diodes are generally incapable of dissipating much energy before they fail. A failed diode may look like an open circuit or a short circuit, but is more likely to fail short.
How to use TVS diodes for transient voltage suppresison?
The primary way to protect a circuit from overvoltage is to place these TVS devices in parallel with the circuit. There are many types of TVS device that can be used for Transient Voltage Suppression namely Metal Oxide Varistor, TVS Diode, Zener Diode or a Bypass Capacitor.
What do I need to know about a TVS diode?
It is the Maximum voltage drop across the TVS diode for a particular peak pulse current. Clamping Voltage (VC). The first step in selecting a TVS diode is to determine What highest continuous peak normal operating voltage will be at the point of intended protection in the circuit.
What is the clamping ratio of TVS diodes?
The ratio of VC/VBR is known as the Clamping Factor. The ratio of Clamping Voltage to Working Peak Voltage (VC/VWM) is known as the Voltage Clamping Ratio. Neither the Clamping Factor nor the Voltage Clamping Ratio is directly shown on TVS diode data sheets. Clamping ratios for TVS diodes are significantly lower than Metal Oxide Varistors MOV.
When does the clamping of a transient diode occur?
The actual clamping occurs in roughly one picosecond, but in a practical circuit the inductance of the wires leading to the device imposes a higher limit. This makes transient-voltage-suppression diodes useful for protection against very fast and often damaging voltage transients.