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When selecting a TVS (Transient Voltage Suppressor) diode, engineers usually start from three basic points: package type, peak pulse power and working voltage range. This quick guide focuses on three popular SMD options widely used in power supplies, chargers, LED drivers and industrial boards: SMAJ, SMBJ and SMCJ TVS diodes.
Use this page as a keyword-rich entrance and as a fast shortcut to detailed product pages, datasheets and application decisions.
SMBJ / SMAJ / SMCJ – Quick Comparison Table
The table below summarizes the most commonly used TVS series in compact power designs. You can quickly compare package size, wattage and typical applications, then jump to the corresponding product page.
| Series | Package | Peak Pulse Power | Voltage Range | Typical Uses | Product Page |
|---|---|---|---|---|---|
| SMAJ | SMA | 400 W | 5.0–440 V | Compact SMPS, telecom, adapter boards | View SMAJ TVS series |
| SMBJ | SMB | 600 W | 5.0–440 V | SMPS output lines, industrial control boards | View SMBJ TVS series |
| SMCJ | SMC | 1500 W | 5.0–440 V | High-power PSU, automation and industrial systems | View SMCJ TVS series |
Extended TVS Options – Axial Series
For designs that prefer axial-leaded TVS diodes with higher surge capability or easier retrofit into existing layouts, the following series are frequently selected:
- 1.5KE Series – High surge 1500 W TVS for robust power lines
Download 1.5KE datasheet - P4KE Series – General-purpose 400 W transient suppressor
Download P4KE datasheet - P6KE Series – 600 W TVS for switching power supply protection
Download P6KE datasheet - SA5.0A Series – 500 W TVS for low-voltage signal and control lines
Download SA5.0A datasheet
Voltage & Wattage Checklist
For quick decision-making, engineers often filter TVS diodes by wattage class first:
- 400 W class – SMAJ, P4KE
Suitable for compact boards, adapters, telecom modules and low-to-medium surge levels. - 600 W class – SMBJ, P6KE
Used in SMPS outputs, industrial control, distribution boards and general-purpose protection. - 1500 W class – SMCJ, 1.5KE
Preferred for high-energy industrial lines, motor drives and harsh surge environments.
Within each series, voltage options typically span from 5.0 V up to 440 V, allowing engineers to match the TVS standoff voltage and clamping level to the system’s normal operating range.
TVS Diode Basics – Reference Video
If you want a quick visual review of avalanche behavior, clamping voltage and surge waveforms, the following video is a helpful complement to this selection guide:
TVS Diode Basics & Surge Protection Explained
Use the video together with the comparison table above to align theory, waveforms and real-world part numbers from the SMAJ, SMBJ, SMCJ and axial TVS families.
Full TVS Diode Comparison – All Series
For detailed voltage lists, clamping curves, package drawings and complete selection across multiple series, visit the full Kingtronics TVS page:
Visit Full TVS Diode Comparison →
Engineering & Sales Support
Need help selecting the right TVS diode for your power supply, charger, LED driver or industrial controller? The Kingtronics team can assist with:
- Cross-reference from existing TVS part numbers
- Selection by surge level, package and voltage
- Recommendations for new projects and redesigns
Contact Kingtronics engineering & sales team →
FAQ – TVS Diodes for Power Supplies & Industrial Electronics
1. What does a TVS diode do?
A TVS (Transient Voltage Suppressor) diode protects circuits from voltage spikes, ESD, and surge events. It clamps excessive voltage within nanoseconds to prevent damage to power supplies, chargers, LED drivers, and industrial equipment.
2. When should I use SMAJ, SMBJ or SMCJ?
Use SMAJ for compact 400W protection, SMBJ for 600W medium-surge power lines, and SMCJ for high-energy 1500W industrial and automation systems.
3. How do I choose the correct TVS standoff voltage?
Select a standoff voltage (VRWM) slightly above the circuit’s normal operating voltage. This prevents unnecessary clamping and ensures reliable surge absorption.
4. What is clamping voltage in a TVS diode?
Clamping voltage is the maximum voltage the TVS allows during a surge event. Lower clamping voltage means better protection for sensitive ICs and power stages.
5. What TVS diode wattage is best for industrial electronics?
Industrial systems typically need 600W (SMBJ) or 1500W (SMCJ / 1.5KE) due to higher surge levels, inductive loads, and harsh electrical environments.
6. Are axial TVS diodes still used today?
Yes. Axial series such as P4KE, P6KE, 1.5KE, SA5.0A remain popular for retrofitting, high-energy surge paths, and designs requiring leaded components.
7. Can TVS diodes protect both AC and DC circuits?
Yes. Unidirectional parts are commonly used for DC rails, while bidirectional models protect AC lines, communication interfaces, and reversible power stages.
8. Where can I find all Kingtronics TVS part numbers?
All SMAJ, SMBJ, SMCJ, P4KE, P6KE, 1.5KE, and SA5.0A series are listed here:
Full TVS Diode Comparison →
Follow Kingtronics for More TVS Insights
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