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Vishay General Semiconductor - Diodes Division SMAJ85AHM3/H
- Part No.:
- SMAJ85AHM3/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85AHM3/H.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,646
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Product details
Overview
SMAJ85AHM3/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features 85 V standoff voltage (VWM), 94.4–104 V breakdown voltage (VBR at 1 mA), and clamps transients to ≤137 V at 2.2 A peak pulse current (IPPM) under 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ85AHM3/H datasheet, SMAJ85AHM3/H pinout, SMAJ85AHM3/H application, or SMAJ85AHM3/H equivalent, key selection criteria include its AEC-Q101 qualification, halogen-free RoHS-compliant HM3 suffix, 400 W peak pulse power rating (derated to 300 W above 78 V), low 0.106 %/°C VBR temperature coefficient, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This unidirectional TVS diode operates as a clamping device across DC supply lines or I/O paths, activating when reverse voltage exceeds VBR to divert surge current away from protected circuitry. Its glass-passivated junction ensures stable leakage (<1.0 μA at 85 V) and fast response time (<1.0 ps), critical for suppressing ESD and inductive switching transients.
The SMAJ85AHM3/H is rated for 40 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine), supports operating junction temperatures from –55 °C to +150 °C, and meets MSL Level 1 per J-STD-020 with 260 °C reflow peak - confirming suitability for high-reliability automotive and industrial PCB assembly.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 12 V/24 V/48 V systems. |
| VBR (min/max) | 94.4 V / 104 V at 1 mA - precise breakdown threshold ensuring predictable turn-on during transients without premature conduction. |
| VC @ IPPM | ≤137 V at 2.2 A - clamping voltage limits stress on downstream ICs (e.g., microcontrollers, CAN transceivers) during surge events. |
| PPPM | 400 W (10/1000 μs) - peak pulse power handling capacity; derates to 300 W above 78 V per spec sheet note (1). |
| IFSM | 40 A - surge current withstand capability for single half-sine pulses, supporting protection against load dump in automotive 12 V systems. |
| TJ max | +150 °C - enables operation in under-hood automotive environments and thermally constrained industrial enclosures. |
| RθJA | 120 °C/W - thermal resistance from junction to ambient on standard 0.2" × 0.2" copper pads; informs board-level thermal design. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Cathode indicated by band marking; polarity-critical for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or return path; completes clamping loop when cathode is tied to protected line. |
| Cathode | High-side connection point | Connected to protected signal/power line; reverse-biased during normal operation, avalanches during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - required for engine control, ADAS, and body electronics. |
| Halogen-free & RoHS-compliant (HM3) | Meets global environmental regulations and JEDEC JESD201 Class 2 whisker resistance - suitable for export-controlled and green manufacturing programs. |
| 400 W peak pulse power (10/1000 μs) | Provides robust immunity against ISO 7637-2 Pulse 1/2a/3a and IEC 61000-4-5 surges without derating in most 24 V industrial applications. |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (e.g., relay coil flyback), improving protection margin for 3.3 V/5 V logic interfaces. |
| MSL Level 1 (260 °C peak) | Enables single-pass lead-free reflow without moisture sensitivity concerns - eliminates bake requirements and streamlines SMT production. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
|
Use Scenario: Protecting 12 V battery-fed microcontroller power inputs in vehicle body control modules against load dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between VIN and GND, conducting only during negative-going surges on the supply rail. Use Value: Limits clamped voltage to ≤137 V while handling 400 W surges, preventing brownout or latch-up in MCUs and PMICs compliant with ISO 16750-2. |
Use Scenario: Shielding analog output lines (e.g., 4–20 mA current loop) of pressure sensors in factory automation PLCs from ESD and cable-induced transients. IC Role / Device Role / Timing Role: Bidirectional-capable unidirectional TVS used across signal and return, leveraging low capacitance (<100 pF) to avoid signal integrity degradation. Use Value: Clamps transients to <137 V within nanoseconds, preserving sensor accuracy and eliminating false triggers in safety-critical monitoring systems. |
| Telecom DC Power Input Protection | Consumer Device USB Port Protection |
|
Use Scenario: Safeguarding 48 V PoE-powered network switches from lightning-induced surges entering via Ethernet cables. IC Role / Device Role / Timing Role: Primary TVS on DC input stage, coordinated with upstream MOVs and secondary filtering to meet IEC 61000-4-5 Level 4. Use Value: Withstands 2.2 A peak pulse current at 137 V clamp, enabling compact front-end protection without thermal runaway in sealed telecom enclosures. |
Use Scenario: Adding secondary overvoltage protection on VBUS line of USB-C ports in portable monitors and docking stations. IC Role / Device Role / Timing Role: Fast-response unidirectional TVS placed after primary ESD array, absorbing residual energy from contact discharge events. Use Value: Low leakage (<1.0 μA at 85 V) prevents standby current drain; 0.106 %/°C VBR TC ensures stable clamping across operating temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85AHE3/H | Same electrical specs, but RoHS-compliant commercial grade (E3) - not halogen-free or AEC-Q101 qualified. | Lacks automotive qualification and halogen-free compliance; suitable for consumer/industrial designs without AEC or green mandates. | Select SMAJ85AHE3/H if AEC-Q101 and halogen-free requirements are not mandated, and cost optimization is prioritized. |
| SMBJ85A-H | Same VWM/VBR/VC, but SMB (DO-214AA) package - 20 % larger footprint, higher RθJA (100 °C/W), 600 W PPPM. | Higher power rating supports heavier-duty surge events; larger pad area eases thermal management but consumes more board space. | Choose SMBJ85A-H where 600 W surge margin is needed and PCB layout allows larger package; SMAJ85AHM3/H preferred for space-constrained automotive modules. |
Compared with SMAJ85AHE3/H, the SMAJ85AHM3/H adds halogen-free construction and AEC-Q101 validation without sacrificing clamping performance; versus SMBJ85A-H, it trades 200 W peak power for 25 % smaller footprint and tighter thermal constraints - making it optimal for high-density automotive PCBs requiring certified reliability.
Availability
SMAJ85AHM3/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, and telecom power input stages requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ85AHM3/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, efficiency, and application-specific optimization.
The SMAJ series delivers standardized, high-power TVS protection in compact surface-mount packages - engineered for automotive, industrial, and communications systems demanding AEC-Q101 validation and consistent surge immunity.
FAQ
What is the clamping voltage of the SMAJ85AHM3/H under maximum rated surge current?
The SMAJ85AHM3/H clamps to a maximum of 137 V when subjected to its rated peak pulse current of 2.2 A (10/1000 μs waveform). This value is measured per standard test conditions in the Vishay datasheet (Document Number: 88390, Rev. 09-Jan-2024) and defines the upper voltage limit imposed on protected circuitry during transient events - critical for ensuring downstream ICs remain within absolute maximum ratings.
Is the SMAJ85AHM3/H suitable for automotive applications requiring AEC-Q101 qualification?
Yes, the SMAJ85AHM3/H is explicitly AEC-Q101 qualified, as confirmed by Vishay's ordering information table (page 3) and "Notes" section (Note 1). The "HM3" suffix denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction - making SMAJ85AHM3/H appropriate for under-hood, chassis, and ADAS applications where automotive-grade reliability is mandatory.
How does the thermal resistance of the SMAJ85AHM3/H affect PCB layout design?
The SMAJ85AHM3/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2" × 0.2" copper pads per terminal. To maintain TJ ≤ 150 °C under worst-case 3.3 W steady-state dissipation, designers must ensure adequate copper area and airflow - underscoring why the datasheet specifies minimum pad dimensions and warns against reduced thermal performance on smaller land patterns.
What is the meaning of the "HM3" suffix in SMAJ85AHM3/H?
The "HM3" suffix in SMAJ85AHM3/H indicates halogen-free, RoHS-compliant construction with AEC-Q101 qualification - distinct from "E3" (RoHS only) and "HE3" (RoHS + AEC-Q101, not halogen-free). Per Vishay's ordering table (page 3), HM3 devices meet JESD201 Class 2 whisker resistance and UL 94 V-0 flammability, fulfilling strict environmental and reliability requirements for automotive and industrial deployments.
Can the SMAJ85AHM3/H be used in bidirectional protection circuits?
No - the SMAJ85AHM3/H is a unidirectional TVS diode, as indicated by the "A" (not "CA") suffix and cathode band marking. For bidirectional protection, Vishay offers the SMAJ85CA variant. Using SMAJ85AHM3/H in reverse-biased configurations risks permanent damage; it must be oriented with cathode toward the protected line and anode to ground to function correctly as a clamping device.
SMAJ85AHM3/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 2.2A
- Power - Peak Pulse:
- 400W
- 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-214AC (SMA)
SMAJ85AHM3/H FAQ
1.How can I place an order for SMAJ85AHM3/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85AHM3/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 SMAJ85AHM3/H reliable?
The price and inventory of SMAJ85AHM3/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85AHM3/H is usually 5 days.
3.What payment methods are accepted for SMAJ85AHM3/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85AHM3/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85AHM3/H?
SMAJ85AHM3/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85AHM3/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 SMAJ85AHM3/H?
For technical support, including SMAJ85AHM3/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85AHM3/H requirements.
6.How does Aetrix verify that SMAJ85AHM3/H is sourced from the original manufacturer or authorized distributors?
All SMAJ85AHM3/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 SMAJ85AHM3/H meets industry standards.
7.What is the process for return or replacement of SMAJ85AHM3/H?
All SMAJ85AHM3/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85AHM3/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 SMAJ85AHM3/H part is unused and in its original packaging.
Return procedure for SMAJ85AHM3/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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