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Vishay General Semiconductor - Diodes Division SMB8J18CAHM3_B/H
- Part No.:
- SMB8J18CAHM3_B/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMB8J18CAHM3_B/H.pdf
- Description:
- 800W,18V 5%,BIDIR,SMB TVS
- Quantity:
- Payment:
- Shipping:
Inventory:6,663
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Product details
Overview
SMB8J18CAHM3_B/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed for high-energy surge protection on signal and power lines. It features a 18 V stand-off voltage (VWM), 29.2 V maximum clamping voltage (VC) at 27.4 A peak pulse current (IPPM), and 800 W peak pulse power (PPPM) with 10/1000 µs waveform - deployed in automotive sensor interfaces and industrial I/O protection.
For engineers reviewing the SMB8J18CAHM3_B/H datasheet, SMB8J18CAHM3_B/H pinout, SMB8J18CAHM3_B/H application, or SMB8J18CAHM3_B/H equivalent, key selection criteria include bidirectional clamping performance, AEC-Q101 qualification, low thermal resistance (RθJL = 20 °C/W), and compatibility with automated SMT assembly on 5.0 mm × 5.0 mm copper pads.
Technical Context
This device operates as a voltage-clamping protector using an avalanche breakdown junction, responding within <1 ps to transients induced by inductive switching or ESD events. Its bidirectional symmetry enables protection of AC-coupled or differential lines without polarity constraints.
Designed per ANSI/IEEE C62.35 standards, it delivers stable clamping under repetitive surges up to TJ = 150 °C, with derating defined in Fig. 2 and validated on minimum recommended pad layout per JEDEC MS-012. The glass-passivated chip junction ensures robustness against moisture and mechanical stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping initiates; defines safe operating margin for 12 V automotive or 15 V industrial bus lines. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1.0 mA - verified breakdown threshold ensures predictable turn-on across temperature and lot variation. |
| VC @ IPPM | 29.2 V at IPPM = 27.4 A - clamping voltage limits downstream IC stress during 800 W transient events (10/1000 µs). |
| PPPM | 800 W - peak pulse power rating determines survivability against lightning-induced surges (IEC 61000-4-5 Level 3/4) on bidirectional lines. |
| ID @ VWM | 1.0 µA - ultra-low leakage preserves signal integrity and battery life in always-on sensor circuits. |
| TJ max. | 150 °C - junction temperature limit supports operation in under-hood automotive environments and sealed industrial enclosures. |
| RθJL | 20 °C/W - low junction-to-lead thermal resistance enables efficient heat transfer to PCB copper, critical for sustained surge duty cycles. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, AEC-Q101 qualified. Matte tin-plated leads, MSL level 1 (260 °C peak reflow). No polarity marking - bidirectional device.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Transient conduction path | Both terminals function identically; clamps voltage in either direction when |V| exceeds VBR - eliminates orientation concerns during placement. |
| Case (cathode band absent) | Thermal and mechanical interface | Exposed metal slug provides primary thermal path to PCB copper pads; requires 5.0 mm × 5.0 mm minimum pad area per terminal per datasheet Fig. 6. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock - suitable for engine control, ADAS sensor, and infotainment modules. |
| Low incremental surge resistance | Enables tighter clamping (VC/VBR ratio = 1.46) versus standard TVS diodes, reducing voltage overshoot on protected lines during fast-rising transients. |
| Glass passivated junction | Prevents moisture ingress and electromigration under high-humidity or high-bias conditions - extends lifetime in harsh industrial environments. |
| MSL level 1 rating | Allows unlimited floor life and single-reflow processing at 260 °C peak without popcorn cracking or delamination. |
| Halogen-free construction (HM3 suffix) | Meets IEC 61249-2-21 and JEDEC J-STD-020 requirements for green electronics manufacturing and end-of-life recycling compliance. |
Applications
| Automotive Sensor Interface Protection | Industrial RS-485 Transceiver Protection |
|---|---|
|
Use Scenario: Protecting CAN FD or LIN bus nodes from load-dump and jump-start transients in vehicle body control modules. IC Role / Device Role / Timing Role: Bidirectional clamping element placed directly at connector entry point, shunting surge energy to ground before reaching PHY IC. Use Value: Withstands 800 W pulses while limiting line voltage to ≤29.2 V, preventing damage to 3.3 V or 5 V transceivers compliant with ISO 11898-2/3. |
Use Scenario: Safeguarding half-duplex RS-485 communication lines in factory automation PLCs exposed to motor drive noise and relay switching spikes. IC Role / Device Role / Timing Role: Differential-line TVS mounted across A/B bus pair, providing symmetrical overvoltage clamping independent of signal polarity. Use Value: 27.4 A IPPM capability handles repetitive 1 kV/500 Ω surges (IEC 61000-4-5) without degradation, maintaining data integrity over 10+ years in 24/7 operation. |
| Consumer USB Type-C ESD Protection | Medical Patient Monitor Signal Line Guarding |
|
Use Scenario: Secondary-level surge suppression on USB Type-C CC and VCONN lines after primary ESD array, targeting slower but higher-energy transients. IC Role / Device Role / Timing Role: Standoff-voltage-matched TVS that activates only after fast ESD components (e.g., 0201 MLV) saturate - avoids crowbar behavior during normal operation. Use Value: 1.0 µA leakage at 18 V prevents loading of precision CC line biasing networks, preserving USB PD negotiation accuracy. |
Use Scenario: Protecting analog front-end inputs (ECG, SpO₂) from defibrillator-induced surges and electrostatic discharge in portable patient monitors. IC Role / Device Role / Timing Role: Low-capacitance (<100 pF typical at 0 V) bidirectional clamp placed immediately before instrumentation amplifier input stage. Use Value: Clamps 800 W transients to ≤29.2 V while adding negligible noise or signal distortion - meets IEC 60601-1-2 immunity requirements for Class BF equipment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMB8J18CAHE3_B/H | Same electrical specs and AEC-Q101 qualification, but RoHS-compliant with brominated flame retardants (non-halogen-free). | Acceptable for commercial/industrial use where halogen-free mandate does not apply; not approved for automotive OEM Tier 1 supply chains requiring HM3. | Select SMB8J18CAHE3_B/H only if halogen content is unrestricted and cost sensitivity outweighs green compliance requirements. |
| SMAJ18CA-M3/5B | Lower PPPM (400 W), smaller SMA package (DO-214AC), higher RθJA (110 °C/W), same VWM/VC specs. | Suitable for space-constrained consumer boards with lower surge threat levels (IEC 61000-4-2 only); insufficient for automotive load-dump or industrial 4-20 mA loop protection. | Choose SMAJ18CA-M3/5B only for non-automotive, low-power signal lines where board area is critical and surge energy is ≤400 W. |
Compared with SMB8J18CAHE3_B/H, the SMB8J18CAHM3_B/H offers halogen-free compliance essential for automotive Tier 1 sourcing, while versus SMAJ18CA-M3/5B, its 800 W rating and superior thermal performance enable robust protection in high-energy industrial and automotive environments - no compromise on clamping voltage or leakage.
Availability
SMB8J18CAHM3_B/H is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial RS-485 networks, and medical analog signal conditioning requiring stable component supply, long-term lifecycle support, and AEC-Q101 traceability.
Supply support for SMB8J18CAHM3_B/H includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, MOSFETs, optoelectronics, and passive components with emphasis on reliability, power density, and automotive qualification.
The SMB8JxxCA series belongs to Vishay's TRANSZORB® high-power TVS platform, engineered specifically for AEC-Q101-compliant surge protection in harsh-environment automotive and industrial control systems.
FAQ
What is the clamping voltage of SMB8J18CAHM3_B/H at its rated peak pulse current?
The SMB8J18CAHM3_B/H has a maximum clamping voltage (VC) of 29.2 V when subjected to its peak pulse current (IPPM) of 27.4 A under the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and confirmed in the Vishay datasheet Document Number 88422, page 3 (Bidirectional table). The low VC ensures protected downstream ICs remain within safe operating voltage limits during surge events.
Is SMB8J18CAHM3_B/H suitable for automotive applications?
Yes, SMB8J18CAHM3_B/H is AEC-Q101 qualified and carries the HM3 suffix indicating halogen-free, RoHS-compliant construction - meeting Tier 1 automotive supplier requirements. It is explicitly rated for operation from –55 °C to +150 °C junction temperature and validated for temperature cycling, humidity bias, and mechanical shock. The SMB8J18CAHM3_B/H is deployed in engine control units, ADAS camera modules, and body electronics where robust transient immunity is mandatory.
How does the SMB8J18CAHM3_B/H differ from unidirectional variants like SMB10J18A?
The SMB8J18CAHM3_B/H is bidirectional with symmetric clamping in both polarities, whereas SMB10J18A is unidirectional and conducts only in reverse bias. SMB8J18CAHM3_B/H has a lower peak pulse power rating (800 W vs. 1000 W) and slightly higher clamping voltage (29.2 V vs. 29.2 V - same value but tested at different IPPM), reflecting its dual-path design. Its breakdown voltage range (20.0–22.1 V) matches SMB10J18A, but the "C" in the part number denotes bidirectionality - critical for AC or differential signal protection.
What PCB layout guidance applies to SMB8J18CAHM3_B/H for optimal thermal and surge performance?
Vishay specifies mounting SMB8J18CAHM3_B/H on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal to achieve rated PPPM and thermal performance. The SMB8J18CAHM3_B/H datasheet (page 5) shows minimum pad dimensions and recommends solder mask defined pads to maximize copper area. Avoid thermal reliefs on these pads; use multiple vias to internal ground planes to reduce RθJA. Failure to meet pad size de-rates IPPM and increases risk of solder joint fatigue during repeated surges.
Does SMB8J18CAHM3_B/H require polarity-aware placement on the PCB?
No - SMB8J18CAHM3_B/H is a bidirectional TVS diode with symmetrical electrical characteristics; there is no cathode band or polarity marking on the SMB (DO-214AA) package. Both terminals perform identically, enabling placement flexibility and eliminating orientation errors during automated assembly. This feature simplifies layout for differential buses (e.g., RS-485, CAN) and reduces manufacturing defect rates compared to unidirectional alternatives like SMB10J18A.
SMB8J18CAHM3_B/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 18V
- Current - Peak Pulse (10/1000µs):
- 27.4A
- Power - Peak Pulse:
- 800W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMB8J18CAHM3_B/H FAQ
1.How can I place an order for SMB8J18CAHM3_B/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB8J18CAHM3_B/H on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMB8J18CAHM3_B/H reliable?
The price and inventory of SMB8J18CAHM3_B/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB8J18CAHM3_B/H is usually 5 days.
3.What payment methods are accepted for SMB8J18CAHM3_B/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB8J18CAHM3_B/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB8J18CAHM3_B/H?
SMB8J18CAHM3_B/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB8J18CAHM3_B/H order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMB8J18CAHM3_B/H?
For technical support, including SMB8J18CAHM3_B/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB8J18CAHM3_B/H requirements.
6.How does Aetrix verify that SMB8J18CAHM3_B/H is sourced from the original manufacturer or authorized distributors?
All SMB8J18CAHM3_B/H products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMB8J18CAHM3_B/H meets industry standards.
7.What is the process for return or replacement of SMB8J18CAHM3_B/H?
All SMB8J18CAHM3_B/H units undergo pre-shipment inspection (PSI). If there is an issue with SMB8J18CAHM3_B/H, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMB8J18CAHM3_B/H part is unused and in its original packaging.
Return procedure for SMB8J18CAHM3_B/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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