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Vishay General Semiconductor - Diodes Division SMBJ18AHM3/H
- Part No.:
- SMBJ18AHM3/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18AHM3/H.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,804
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Product details
Overview
SMBJ18AHM3/H from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed to protect sensitive electronics against ESD, lightning-induced surges, and inductive switching transients. It features a 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 29.2 V maximum clamping voltage (VC) at 20.5 A peak pulse current (IPPM), and 600 W peak pulse power (10/1000 µs waveform).
For engineers reviewing the SMBJ18AHM3/H datasheet, SMBJ18AHM3/H pinout, SMBJ18AHM3/H application, or SMBJ18AHM3/H equivalent, this device is selected for robust overvoltage protection on DC power rails and signal lines in industrial sensors, automotive ECUs, and telecom interface circuits where low clamping voltage and fast response (<1 ns) are critical.
Technical Context
This unidirectional TVS operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 µA leakage at 18 V), then rapidly avalanches below 29.2 V to divert surge energy away from downstream ICs or MOSFETs. Its glass-passivated junction ensures stable VBR tolerance and long-term reliability under repetitive surge stress.
Designed for surface-mount assembly on standard PCB copper pads (0.2" × 0.2"), SMBJ18AHM3/H delivers 600 W peak pulse power with 0.01% duty cycle, derates linearly above 25 °C ambient (RθJA = 100 °C/W), and supports 100 A non-repetitive forward surge (8.3 ms half-sine) - confirming suitability for high-energy transient suppression in 12–24 V systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 18 V - Maximum continuous reverse operating voltage before significant leakage; sets threshold for protection activation in 18 V nominal systems. |
| VBR (Breakdown Voltage) | 20.0–22.1 V at 1 mA - Confirmed avalanche onset range; ensures reliable triggering without premature conduction during normal operation. |
| VC (Clamping Voltage) | 29.2 V at IPPM = 20.5 A - Peak voltage seen by protected circuit during worst-case 600 W surge; enables safe margin for 3.3 V/5 V/12 V ICs. |
| PPPM (Peak Pulse Power) | 600 W (10/1000 µs waveform) - Sustains standardized lightning/surge energy per IEC 61000-4-5; validates compliance with industrial surge immunity requirements. |
| IR (Reverse Leakage) | 1.0 µA max. at VWM - Negligible standby current draw; avoids loading of low-power sensor or battery-backed circuits. |
| TJ max. | 150 °C - Enables operation in under-hood automotive or enclosed industrial enclosures without thermal derating concerns. |
| Package | SMB (DO-214AA) - Industry-standard 2-pin SMD outline; compatible with automated pick-and-place and reflow profiles up to 260 °C peak (MSL Level 1). |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, cathode-band marked end. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H); matte tin-plated leads, J-STD-002 solderable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to system ground or return path; completes clamping loop during transient events. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12 V rail or RS-485 A/B); avalanche conduction occurs from cathode to anode during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Validated for IEC 61000-4-5 Level 4 surge immunity testing on 12–24 V DC inputs without external series impedance. |
| 29.2 V clamping at 20.5 A | Provides ≥3.8 V margin below 33 V absolute maximum rating of common 24 V-rated microcontrollers and CAN transceivers. |
| Halogen-free, RoHS-compliant (HM3 suffix) | Meets IPC-JEDEC J-STD-020 MSL Level 1 and JESD201 Class 2 whisker resistance - suitable for high-reliability industrial and automotive production. |
| Fast response time (<1 ns) | Clamps transients before propagation into IC input stages, preventing latch-up or gate oxide damage in MOSFET drivers and logic interfaces. |
| AEC-Q101 qualified option available | Base P/N HM3_X variant (e.g., SMBJ18AHM3/H) supports automotive-grade qualification when ordered with revision suffix (e.g., /H denotes revision code). |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
|
Use Scenario: Protecting 12 V supply rail and LIN bus lines from load-dump and jump-start transients in vehicle body control units. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between power rail and chassis ground; clamps >100 V spikes to ≤29.2 V within nanoseconds. Use Value: Prevents permanent damage to MCU power domains and LIN transceivers during ISO 7637-2 Pulse 5a (load dump) events. |
Use Scenario: Shielding 24 V digital input channels from field-wiring induced surges in programmable logic controller backplanes. IC Role / Device Role / Timing Role: Front-end transient suppressor on each optocoupler input; absorbs 600 W surges while maintaining <1 µA leakage at 24 V. Use Value: Eliminates false triggering and extends service life of isolation components in factory automation environments. |
| Telecom Remote Radio Unit (RRU) | Consumer Smart Home Gateway Power Supply |
|
Use Scenario: Safeguarding 48 V DC power feed lines in outdoor wireless base station radios exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary clamping device upstream of DC-DC converters; conducts 20.5 A peak current to limit voltage excursion to 29.2 V. Use Value: Maintains uninterrupted operation during Category C2/C3 surge events per IEC 61000-4-5 without requiring redundant protection stages. |
Use Scenario: Securing 12 V auxiliary power rail feeding Wi-Fi SoCs and USB peripherals in residential gateway devices. IC Role / Device Role / Timing Role: Low-profile TVS mounted adjacent to power entry connector; activated only during ESD or capacitive coupling events. Use Value: Reduces BOM count by enabling single-stage protection with no additional series resistors or ferrites required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18A-E3/52 | RoHS-compliant commercial grade (E3), not halogen-free; same VWM/VBR/VC specs and SMB package. | Lacks halogen-free certification and JESD201 Class 2 whisker resistance; unsuitable for automotive or high-reliability industrial use. | Select SMBJ18A-E3/52 only for cost-sensitive consumer applications where halogen-free and whisker resistance are not mandated. |
| SMBJ18AHM3/B | Identical electrical specs and HM3 halogen-free construction; differs only in packaging - 3200-unit 13" tape-and-reel (B) vs. 750-unit 7" reel (H). | No functional difference; choice depends solely on production volume and SMT line feeder compatibility. | Choose SMBJ18AHM3/B for high-volume automated assembly; SMBJ18AHM3/H is optimal for prototyping and low-to-mid volume builds. |
Compared with SMBJ18A-E3/52, SMBJ18AHM3/H adds halogen-free compliance and whisker resistance for harsh environments; versus SMBJ18AHM3/B, it offers smaller reel size for flexibility without sacrificing performance or qualification.
Availability
SMBJ18AHM3/H is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC input cards, telecom remote radio units, and consumer smart home gateway power supplies requiring stable component supply and full traceability.
Supply support for SMBJ18AHM3/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, rectifiers, TVS devices, and MOSFETs with emphasis on reliability, efficiency, and application-specific optimization.
The SMBJ series was engineered for high-energy transient suppression in space-constrained, high-reliability applications - particularly automotive, industrial, and telecom systems demanding AEC-Q101 qualification and halogen-free materials.
FAQ
What is the maximum clamping voltage of SMBJ18AHM3/H under rated surge conditions?
The SMBJ18AHM3/H has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current of 20.5 A (10/1000 µs waveform). This value is measured per ANSI/IEEE C62.35 and guarantees that protected downstream circuitry sees no more than 29.2 V during a full 600 W transient event - critical for ensuring compatibility with 3.3 V, 5 V, and 12 V ICs. The SMBJ18AHM3/H maintains this clamping performance across its full operating temperature range.
Is SMBJ18AHM3/H suitable for automotive applications?
Yes - SMBJ18AHM3/H is built on Vishay's AEC-Q101 qualified platform (denoted by the HM3 suffix and revision code /H). It meets automotive-grade requirements including MSL Level 1, JESD201 Class 2 whisker resistance, and operation from –55 °C to +150 °C. While the base part number does not include "HE3" or "HM3_X" in the marking, the /H suffix confirms revision-controlled AEC-Q101 qualification, making SMBJ18AHM3/H appropriate for body electronics, infotainment power rails, and sensor interfaces in passenger vehicles.
How does the HM3 suffix differ from E3 in SMBJ18AHM3/H?
The HM3 suffix in SMBJ18AHM3/H indicates halogen-free, RoHS-compliant construction with JESD201 Class 2 whisker resistance - exceeding the baseline E3 (RoHS-compliant only) specification. Both share identical electrical parameters (VWM = 18 V, VC = 29.2 V), but HM3 adds material compliance for high-reliability applications such as automotive and industrial equipment where long-term lead-tin intermetallic stability and flame-retardant chemistry are mandatory. The SMBJ18AHM3/H therefore supports stricter environmental and safety standards than SMBJ18A-E3/52.
What is the thermal resistance of SMBJ18AHM3/H, and how does it affect power handling?
SMBJ18AHM3/H has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W when mounted on minimum recommended 0.2" × 0.2" copper pads. This means a 5.0 W steady-state power dissipation (PD) raises the junction temperature by 500 °C above ambient - which is why PD is strictly limited to 5.0 W at TA = 50 °C. For transient suppression, the 600 W peak rating applies only to short-duration pulses (≤50 ms); sustained power must remain within PD limits. Proper PCB copper area is essential to maintain SMBJ18AHM3/H reliability under repeated surge stress.
Can SMBJ18AHM3/H be used in bidirectional signal line protection?
No - SMBJ18AHM3/H is a unidirectional TVS diode, identified by the "A" suffix and cathode band marking. It conducts only in reverse bias (cathode-to-anode) and blocks forward current beyond ~3.5 V. For bidirectional protection (e.g., RS-485, USB D+/D–, or AC-coupled lines), a "CA"-suffixed part like SMBJ18CA must be used. Using SMBJ18AHM3/H on bidirectional lines risks forward conduction during normal signal swings, potentially disrupting communication or damaging drivers. Always match polarity suffix to circuit topology.
SMBJ18AHM3/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 20.5A
- Power - Peak Pulse:
- 600W
- 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)
SMBJ18AHM3/H FAQ
1.How can I place an order for SMBJ18AHM3/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18AHM3/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 SMBJ18AHM3/H reliable?
The price and inventory of SMBJ18AHM3/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18AHM3/H is usually 5 days.
3.What payment methods are accepted for SMBJ18AHM3/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18AHM3/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18AHM3/H?
SMBJ18AHM3/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18AHM3/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 SMBJ18AHM3/H?
For technical support, including SMBJ18AHM3/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18AHM3/H requirements.
6.How does Aetrix verify that SMBJ18AHM3/H is sourced from the original manufacturer or authorized distributors?
All SMBJ18AHM3/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 SMBJ18AHM3/H meets industry standards.
7.What is the process for return or replacement of SMBJ18AHM3/H?
All SMBJ18AHM3/H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18AHM3/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 SMBJ18AHM3/H part is unused and in its original packaging.
Return procedure for SMBJ18AHM3/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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