SA48 Circuit Protection

TVS - Diodes

Transient Voltage Suppressor(TVS) diodes are semiconductor devices that are also known as Transient Voltage Surge Suppressors (TVSS) or Transil diodes. TVS diodes are designed to protect sensitive electronics from large and unexpected voltage transients. It is an efficient, cost-effective, compact and thin form-factor that dissipates large amounts of energy and is intended to curb abrupt levels of voltage spikes. It consists of a diode and a metal oxide varistor (MOV) and is placed across the input and output potentials of the electronics.

SA48 is one of the series of the TVS diode. It is a unidirectional well-suited silicon Avalanche diode intended to protect power and data lines from impending suppression of the undesired high voltage and also associated current induced by Electro Magnetic Interference (EMI) and Electro Static Discharge (ESD). The device is rated 4.6V and a peak pulse power of 400 Watts.

Application Field

SA48 is commonly found in the following fields:

• Industrial machinery
• Avionic
• Automotive
• Data bus equipment
• Medical
• Consumer electronics

Working Principle

When used in high-voltage applications, SA48 serve as switches and isolates the circuit. If ESD or EMI energy exceeds the avalanche voltage breakdown, the device will be triggered and prevent the voltage from being transmitted and damage the device or the system.

The working principle of SA48 is as follows: When the voltage on the two terminals is equal, no current will flow through them. When the voltage on one of the two terminals is large enough to exceed the breakdown voltage, a large current flows through the terminals. The current is determined by the source voltage and the breakdown voltage.

The current through the device is limited to a safe level by two resistors. The first resistor is integrated in the device, so it can be formulated by the equations. The second resistor, called the external resistor, is external to the device, which is used to limit the maximum current. The power dissipation of the device is limited by both of them.

SA48 also includes a metal oxide varistor (MOV). The MOV acts as a voltage regulator, clipping off the top part of transient voltage impulses and preventing the SA48 from overload. It also helps reduce noise levels caused by voltage impulses.

SA48 also has a thermal layer that allows the device to withstand high temperature and prevent overheating. This layer helps to regulate the temperature inside the device, ensuring that the diode does not experience any thermal damage.