SMCJ45A

SMCJ45A is a Uni-directional TVS (Transient Voltage Suppressor) Diode, designed to protect electronic circuits against damage due to voltage transients induced by lightning and other transient voltage events. It is designed to protect components from transient voltage which exceeds the peak pulse power dissipation.

Application Field

SMCJ45A is mainly used in applications like telecom modules, power supplies, data line protection, optical modules, instrumentation, domestic appliances, etc. This device is also ideal for protecting ports for interface devices like USB, Serial, Ethernet, Firewire and audio systems. It can also be used in I/O interfaces, co-axial cables, unipolar/bipolar engines, telecommunications lines, and power systems.

Working Principle

SMCJ45A works on the principle of clamping. It works by diverting excess current away from vulnerable components. This is done by connecting the diode between the power and ground pins or between the data lines. In the event of an overvoltage, the diode becomes forward biased, thus drastically reducing the voltage across connected components.

In the off-state, this diode will show no conduction as it has a very high breakdown voltage. Once the voltage exceeds the breakdown voltage of the device, it will start conducting and providing clamping action. Thus, during a transient, the voltage is reduced to a safe level and wont damage the components.

When the transient has passed, the diode will automatically resume to its non-conducting state. This makes it extremely useful when it comes to protecting sensitive electronics from transient voltage spikes.