Introduction  

In recent years, electric vehicles (EVs), such as electric cars and electric bicycles, have been widely adopted globally due to their environmental and energy-saving benefits. However, the electrical systems of electric vehicles are vulnerable to various transient overvoltages during operation, including those caused by lightning, electrostatic discharge (ESD), power switching, and more. These overvoltages can damage circuit components and compromise the safety and reliability of the vehicle. Therefore, selecting appropriate protection components is crucial. Transient voltage suppression (TVS) diodes, as efficient overvoltage protection devices, are widely used in electric vehicles.

Slkor Transient Protection Diode SMF40A product photo

Technical Parameters of the SMF40A  

The SMF40A is a transient voltage suppression diode specifically designed to protect sensitive electronic devices. Its key technical parameters are as follows:

- VRWM (Working Reverse Voltage): 40V, meaning the TVS diode does not conduct at normal operating voltages, ensuring proper circuit operation.

- VBR min (Minimum Breakdown Voltage): 44.4V, the voltage at which the TVS diode begins to conduct, providing overvoltage protection.

- IR (Reverse Leakage Current): 1.0μA, the maximum current flowing through the TVS diode at the working voltage, which is minimal and does not affect normal circuit operation.

- VC (Clamping Voltage): 64.5V, the peak voltage measured across the TVS diode at the peak pulse current under specified waveforms, ensuring the overvoltage is limited to safe levels.

- Package: SOD-123FL, a compact surface-mount package suitable for high-density circuit board designs.

Slkor Transient Protection Diode SMF40A specification

Parameters of Slkor Transient Protection Diode SMF40A

Applications of SMF40A in Electric Vehicles  

- Power Line Protection  

In the power lines of electric vehicles, the SMF40A can be connected in parallel at the power input to suppress transient overvoltages caused by power switching, lightning, and other events. When the voltage exceeds 44.4V, the SMF40A rapidly conducts, diverting the overvoltage to the ground and protecting subsequent circuit components from damage.

- Signal Line Protection  

Signal lines in electric vehicles, such as CAN buses and LIN buses, are susceptible to electromagnetic interference (EMI) and electrostatic discharge (ESD). The SMF40A can be connected in parallel between the signal line and ground to absorb transient overvoltages, ensuring the stability and reliability of signal transmission.

- Battery Management System (BMS) Protection  

The battery management system is a core component of electric vehicles, responsible for monitoring battery status and ensuring battery safety. The SMF40A can be used on the power input and signal lines of the BMS to prevent overvoltage from damaging the system, thereby enhancing battery life and safety.

Advantages of SMF40A in Electric Vehicles  

- Fast Response  

The SMF40A has an extremely fast response time, capable of reacting to transient overvoltages within nanoseconds, quickly diverting the overvoltage to ground or another safe level, thus protecting the device.

- Low Voltage Leakage  

Under normal operating conditions, the SMF40A exhibits high resistance, which does not significantly affect the normal operating voltage. However, when the rated voltage is exceeded, it rapidly transitions to a low-resistance state, diverting the transient overvoltage to ground.

- High Energy Absorption Capability  

The SMF40A can absorb large amounts of energy, protecting the device from overvoltage damage. It can withstand high current and energy shocks, protecting other electronic components.

- Compact Package  

The SOD-123FL package allows the SMF40A to be compact, making it suitable for high-density circuit board designs, meeting the space requirements of electric vehicles.

Case Study  

For example, a specific electric car model uses the SMF40A for overvoltage protection in both the power and signal lines. During actual operation, the vehicle experienced several instances of transient overvoltage caused by lightning and power switching, but due to the effective protection of the SMF40A, the vehicle’s electrical system remained undamaged, ensuring the safety and reliability of the vehicle.

Future Development Trends  

With the continuous advancement of electric vehicle technology, the protection requirements for electrical systems are becoming more stringent. In the future, transient voltage suppression diodes will evolve towards higher performance, smaller size, and lower power consumption. As new energy vehicles continue to gain popularity, the demand for TVS diodes will continue to rise. Therefore, the development and production of higher-performance TVS diodes to meet the needs of electric vehicle development will be an important trend.

Conclusion  

The SMF40A transient voltage suppression diode plays a significant role in electric vehicles. Its fast response, low-voltage discharge, high energy absorption capability, and compact package make it an ideal choice for protecting the electrical systems of electric vehicles. As electric vehicle technology continues to evolve, TVS diodes like the SMF40A will find broader applications, providing strong protection for the safety and reliability of electric vehicles.

About Slkor：

Slkor has research and development offices in Busan, South Korea, Beijing, China, and Suzhou, China. Most of the wafer manufacturing and packaging and testing are carried out within China. The company employs and collaborates with individuals and organizations worldwide, with a laboratory for product performance and reliability testing and a central warehouse located at its headquarters in Shenzhen. Slkor has filed for over a hundred invention patents, offers more than 2,000 product models, and serves over ten thousand customers globally. Its products are exported to countries and regions including Europe, the Americas, Southeast Asia, and the Middle East, making it one of the rapidly growing semiconductor companies in recent years. With well-established management systems and streamlined workflows, Slkor has rapidly enhanced the brand awareness and reputation of its "SLKOR" brand through its outstanding quality and standardized services. Its product range includes three major series: diodes, transistors, and power devices, with recent introductions of new products such as Hall elements and analog devices, expanding its presence in sensors, Risc-v microcontrollers, and other product categories.