A Transient Voltage Suppressor (TVS) is an electronic component used in PCB (Printed Circuit Board) assemblies to protect sensitive electronic circuits from voltage spikes or transients. These voltage spikes can occur for various reasons, such as lightning strikes, electrostatic discharge (ESD), inductive kickback from inductive loads, or switching events in nearby circuits. TVS devices are designed to divert and limit these transient voltages to protect the components and circuits downstream.

Here are some key features and functions of transient voltage suppressors in PCB assemblies:

  1. Voltage Clamping: TVS devices are designed to clamp the voltage across their terminals when it exceeds a certain threshold. This prevents the voltage from rising to levels that could damage sensitive components.
  2. Fast Response: TVS devices have a rapid response time, often in the nanosecond range. This quick response ensures that transient voltage spikes are suppressed before they can cause damage.
  3. Bi-Directional Protection: Some transient voltage suppressor devices can protect against positive and negative voltage transients, making them suitable for bidirectional circuits.
  4. Low Impedance: TVS devices typically have a low impedance under normal operating conditions, allowing the protected circuit to function generally without significant signal degradation.
  5. Resettable or Non-Resettable: Some TVS devices are resettable, which means they can handle multiple transient events over time without permanently degrading. Others are non-resettable and need replacement after they have clamped a certain number of transients.
  6. Packaging: TVS devices come in various packages, including surface-mount devices (SMDs) and through-hole devices, making them suitable for different PCB assembly techniques.
  7. Application-Specific Selection: Different TVS devices are available for various voltage and transient energy levels, allowing designers to choose the appropriate component based on their specific application requirements.

TVS devices are commonly used in PCB assemblies to protect sensitive components such as microcontrollers, integrated circuits, and other semiconductor devices from voltage spikes that could lead to malfunctions or permanent damage. They are a crucial part of circuit protection strategies, especially in applications where reliability and robustness are essential.