Contents
What are bidirectional diodes used for?
Therefore, when only a positive voltage is applied to the signal line to be protected during normal operation, unidirectional TVS diodes can be used to absorb both positive and negative ESD events. When both positive and negative voltage are applied to the signal line to be protected, use bidirectional TVS diodes.
Does TVS diode have polarity?
The -C and -CA diodes are bidirectional, there is no polarity marker. On unidirectional diodes the color band usually denotes the cathode.
Which is better unidirectional or bidirectional TV protection?
The choice of a unidirectional or bidirectional TVSproduct depends on the properties of the circuit beingprotected. Unidirectional TVS products protect signal or DC power nodes with unidirectional signal swings andbidirectional TVS products protect signal or AC powernodes with bidirectional signal swings.
When does the unidirectional TVS diode kick in?
Unidirectional voltage suppressor diode with clamping voltage greater than 3.3 V is sufficient. For the positive spikes, the ESD diode will kick in into action soon after the voltage reaches the clamping voltage. For negative spike, the TVS diode acts as normal diode shorting the signal soon after the forward voltage of the diode is crossed.
What does a bidirectional TVS diode symbol mean?
Symbol of a Bidirectional TVS diode is shown in below image. TVS Diodes are connected in parallel with the device or circuit to be protected. The TVS device is specifically designed to breakdown at a specific voltage level and conducts large amounts of current without sustaining damage.
Which is the simplest unidirectional TVs device?
The simplest unidirectional TVS device is a Zener oravalanche diode as shown in Figure 1. For negative voltagefrom cathode to anode the TVS has high conductivity abovea forward diode drop. For positive voltages there is highimpedance up to the reverse bias breakdown voltage. Abovethe reverse bias breakdown voltage the diode has lowresistance.