As an Authorized Distributor of Semiware (Semiware), Etamicro's technical team has compiled this technical analysis by integrating publicly available information from Semiware's official website and authorized materials. This article covers five core product lines including TVS Diodes, ESD suppressors, Gas Discharge Tubes (GDT), Varistors (MOV), and Semiconductor Discharge Tubes (TSS), as well as core information such as AEC-Q Certified and IATF 16949 Quality System, providing circuit protection selection reference for Automotive Electronics engineers.
01 Company Overview: Comprehensive Circuit Protection Solution Service Provider
Semiware (Semiware) is a high-tech enterprise specializing in the R&D, manufacturing, and marketing of High Reliability circuit protection devices and discrete components, headquartered in Shanghai, China.
The company was jointly founded by several senior technical professionals in the circuit protection industry. The core team has profound technical expertise in overvoltage protection, overcurrent protection, power semiconductors and other fields, committed to becoming an excellent comprehensive circuit protection solution service provider.
Semiware's product lines cover TVS Diodes, ESD suppressors, gas discharge tubes, varistors, semiconductor discharge tubes, PLED protectors, MOSFETs, diodes, transistors and other nine major series, providing multi-language support (Simplified Chinese, English, Korean, Russian, Vietnamese) to serve global customers.
02 TVS Diodes: Transient Suppression with Nanosecond Response
TVS (Transient Voltage Suppressor) is a high-efficiency circuit protection device with response speed up to picosecond to nanosecond level, used to protect sensitive electronic equipment from transient overvoltage damage caused by lightning, surges, electrostatic discharge, etc.
Semiware TVS products are divided into general-purpose, automotive grade, high current series, and high reliability four categories, with packages covering SMA, SMB, SMC, DO-218AB, etc., and peak pulse power covering 200W~30000W.
Core Technical Parameters
| Parameter | Definition | Selection Key Points |
|---|---|---|
Vrwm |
Reverse Working Voltage | Should be ≥ normal circuit working voltage |
Vbr |
Breakdown Voltage | Vbr≈1.1~1.2×Vrwm |
Pppm |
Peak Pulse Power | Select according to surge level (e.g., IEC 61000-4-5) |
Ipp |
Peak Pulse Current | Pppm = Vc × Ipp |
Vc |
Clamping Voltage | Should be lower than the withstand voltage of the protected IC |
Cj |
Junction Capacitance | High-speed signals (HDMI/USB) require low capacitance <1pF |
Automotive Grade TVS Diodes
Semiware's automotive TVS Diodes are AEC-Q101 certified, specifically designed for automotive electronics systems, mainly applied in:
03 ESD Suppressors: Ultra-Low Clamping Voltage, Dedicated for Signal Interfaces
ESD (Electrostatic Discharge) suppressors are specifically designed to protect high-speed data interfaces from electrostatic discharge damage, featuring ultra-low clamping voltage, low junction capacitance, and compact packaging.
Semiware ESD products are divided into automotive grade ESD, general-purpose ESD, polymer ESD, and MLV (Multi-layer Varistors) four series, with packages covering DFN, SOT-23, SOD-323, etc.
ESD vs TVS Comparison
| Comparison Item | ESD Suppressors | TVS Diodes |
|---|---|---|
| Main Protection Target | ESD, minor surges | Surges, lightning, high-energy transients |
| Junction Capacitance | Extremely low (<0.5pF~5pF) | Higher (tens of pF) |
| Clamping Voltage | Ultra-low (close to forward voltage drop) | Higher |
| Application Scenarios | HDMI, USB, RF antennas and other high-speed interfaces | Power ports, long-line drives and other high-power scenarios |
Automotive Grade ESD Suppressors
Semiware's automotive ESD suppressors are AEC-Q101 certified, mainly applied in:
ESD protection level: IEC 61000-4-2 Level 4 (contact discharge ±8kV, air discharge ±15kV)
04 Gas Discharge Tubes (GDT): High Surge Capacity, Primary Lightning Protection
GDT (Gas Discharge Tube) utilizes the principle of inert gas breakdown in a ceramic tube under high voltage to conduct electricity, providing super high surge current capability for circuit protection, typically used as primary lightning protection (first-stage protection).
Key Parameters
| Parameter | Description | Semiware Typical Values |
|---|---|---|
DC Breakdown Voltage |
Voltage at which GDT starts conducting | 75V / 90V / 150V / 230V / 350V, etc. |
Impulse Breakdown Voltage |
Breakdown voltage under fast pulse | ≤1.2× DC breakdown voltage |
Surge Current Capacity |
Maximum current through a single surge | 5kA / 10kA / 20kA (8/20μs) |
Insulation Resistance |
Resistance when not conducting | ≥1GΩ (at room temperature) |
Parasitic Capacitance |
Impact on high-frequency signals | <1pF (extremely low, suitable for high-frequency applications) |
Automotive Grade Ceramic Gas Discharge Tubes
Semiware's automotive ceramic gas discharge tubes are AEC-Q200 certified, mainly applied in scenarios requiring high surge current lightning protection such as vehicle communication base stations and EV charging communication interfaces. Typically used in conjunction with TVS/ESD to form a multi-stage protection architecture: GDT (primary) → TVS (secondary) → ESD (tertiary).
05 Varistors (MOV): High Energy Absorption, Cost-Effective Choice
MOV (Metal Oxide Varistor) is a voltage-sensitive resistor. When the voltage across both ends exceeds the varistor voltage, the resistance drops sharply, thereby limiting overvoltage. It features high energy absorption capability and low cost.
Semiware Varistor Product Classification
Key Selection Parameters
| Parameter | Definition | Selection Suggestions |
|---|---|---|
Vmax |
Maximum Continuous Working Voltage (AC/DC) | AC voltage × 1.2~1.5 times margin |
Vvar |
Varistor Voltage (nominal value) | Vvar≈1.5~2×Vmax (DC) |
Energy Rating |
Single surge absorption energy (J) | Select according to IEC 61000-4-5 level |
Surge Current Capacity |
Ability to withstand surge current (A) | Select in conjunction with energy rating |
06 Semiconductor Discharge Tubes (TSS): Dedicated Protection for Communication Interfaces
TSS (Thyristor Surge Suppressor) is an overvoltage protection device based on thyristor principles, featuring precise breakdown voltage, low holding current, and fast response, specifically designed for communication interfaces (RJ45, SLIC, xDSL) protection applications.
Semiware TSS products are divided into general-purpose, high reliability, automotive grade, and programmable circuit protectors four series.
Typical Application Scenarios
07 Automotive Electronics Applications: Full-System Circuit Protection Solutions
Semiware circuit protection devices are widely used in major automotive electronics systems, providing complete protection solutions for new energy, ADAS, smart cockpit, body control and other scenarios.
New Energy Vehicle Systems
| Application Module | Recommended Protection Devices | Protection Level |
|---|---|---|
| On-Board Charger (OBC) | Automotive Grade TVS + Varistors | IEC 61000-4-5 Level 4 |
| DC Fast Charging Station | GDT + TVS Multi-stage Protection | Lightning Protection + Surge |
| Battery Pack (BMS) | Automotive Grade TVS | Overvoltage + ESD |
| PTC Heater | Automotive Grade TVS + Varistors | Power Port Surge Protection |
ADAS and Smart Cockpit
| Application Module | Recommended Protection Devices | Interface Type |
|---|---|---|
| 77GHz Millimeter-wave Radar | Automotive Grade TVS + ESD | Power + Control Signal |
| Domain Controller | Automotive Grade TVS + ESD | Multiple Power and Data |
| Automotive Ethernet | Automotive Grade ESD (Ultra-low Capacitance) | 100BASE-T1/1000BASE-T1 |
| In-Vehicle Infotainment | Automotive Grade ESD | USB/HDMI/Type-C |
| CAN/LIN Bus | Automotive Grade TVS | 12V/24V System |
Semiware Automotive Reference Designs
08 Selection Quick Reference: Circuit Protection Product Quick Selection
Selection by Application Scenario
| Application Scenario | Main Threat | Preferred Device | Alternative/Supplementary |
|---|---|---|---|
| AC Power Port (Lightning Protection) | Lightning Surge | GDT + MOV | TVS (post-stage) |
| DC Power Port (12/24/48V) | Load Dump, Surge | Automotive Grade TVS | Varistors |
| USB/HDMI/Type-C | ESD | Ultra-low Capacitance ESD | - |
| CAN/LIN Bus | ESD, Surge | Automotive Grade TVS | ESD |
| Ethernet (RJ45) | Surge, ESD | TSS + Transformer Isolation | ESD (secondary) |
| Antenna RF Port | ESD, Lightning Induction | Low Capacitance ESD + GDT | - |
| LED Lighting | Surge | PLED Protector + TVS | - |
Semiware vs International Competitor Comparison
Semiware products can form pin-to-pin alternatives with the following international brands:
Etamicro can provide domestic alternative selection technical support, assisting engineers in BOM cost optimization and supply chain security upgrade.
Etamicro Technical Support
As an Authorized Distributor of Semiware, Etamicro provides complete circuit protection selection technical support for automotive electronics customers: including device selection, reference design recommendations, AEC-Q Certified consultation, IATF 16949 quality system description, sample application assistance, etc. If you need to obtain Semiware's full product series manual or apply for samples, please contact Etamicro FAE Team.
For more Semiware product information or to apply for samples, please contact:
Etamicro(Suzhou) Electronics Technology Co., Ltd.
Phone: 0512-67296568 | Email: guhongtao@etamicro.com