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Vishay General Semiconductor - Diodes Division SMAJ40AHM3/H
- Part No.:
- SMAJ40AHM3/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ40AHM3/H.pdf
- Description:
- TVS DIODE 40VWM 64.5VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,429
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Product details
Overview
SMAJ40AHM3/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode designed for robust overvoltage protection of sensitive electronics. It features a 40 V stand-off voltage (VWM), 44.4–49.1 V breakdown voltage (VBR) at 1 mA, 64.5 V maximum clamping voltage (VC) at 6.2 A peak pulse current, and 400 W peak pulse power dissipation with a 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial motor drives.
For engineers reviewing the SMAJ40AHM3/H datasheet, SMAJ40AHM3/H pinout, SMAJ40AHM3/H application, or SMAJ40AHM3/H equivalent, key selection criteria include clamping performance under 6.2 A surge, thermal resistance (RθJA = 120 °C/W), AEC-Q101 qualification status, and halogen-free RoHS-compliant packaging in SMA (DO-214AC) format.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, activated when reverse voltage exceeds its VBR range (44.4–49.1 V). Its low incremental surge resistance ensures rapid energy diversion during transients induced by inductive switching or ESD events.
The device uses a glass-passivated silicon junction and is rated for -55 °C to +150 °C operating junction temperature. It meets MSL level 1 per J-STD-020 and supports lead-free reflow up to 260 °C peak, with matte tin-plated leads compliant to J-STD-002 and JESD 22-B102.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 44.4 V / 49.1 V at 1 mA - guaranteed avalanche conduction onset window |
| VC @ IPPM | 64.5 V at 6.2 A - clamped voltage during 10/1000 μs surge, limiting downstream stress |
| PPPM | 400 W - peak transient power handling capability under standard waveform |
| ID @ VWM | 1.0 μA - ultra-low leakage ensuring minimal standby power loss |
| RθJA | 120 °C/W - thermal resistance defining junction-to-ambient temperature rise under 3.3 W steady-state dissipation |
| AEC-Q101 | Qualified - validated for automotive-grade reliability including temperature cycling and HTRB |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with cathode band marking. Dimensions: 4.93 mm × 3.99 mm × 2.29 mm (L × W × H); terminals are matte tin-plated for solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse surge return path | Connected to system ground or low-impedance return plane during transient suppression |
| Cathode | Reverse-biased terminal / Clamping node | Connected to protected line (e.g., 40 V rail); band denotes cathode end per polarity convention |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Enables reliable suppression of IEC 61000-4-5 Level 3 surges (1 kV/42 Ω) on 40 V systems without derating |
| AEC-Q101 qualified | Validated for automotive powertrain and body control modules requiring extended lifetime under thermal cycling and humidity |
| Halogen-free & RoHS-compliant | Meets EU Directive 2011/65/EU and IPC-1752A material declaration requirements for green manufacturing |
| MSL Level 1 | Allows unlimited floor life and single-reflow processing without dry-pack or baking preconditioning |
| Low clamping ratio (VC/VBR ≈ 1.36) | Minimizes overvoltage overshoot during fast transients, protecting 48 V-rated MOSFET gates and microcontroller I/O |
Applications
| Automotive Power Distribution | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting 40 V battery-fed circuits in engine control units against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between 40 V rail and chassis ground to shunt >100 V transients within nanoseconds. Use Value: Limits voltage seen by downstream DC-DC converters and CAN transceivers to ≤64.5 V, preventing latch-up or gate oxide rupture. | Use Scenario: Safeguarding analog input channels (e.g., 4–20 mA sensors) in programmable logic controllers exposed to field wiring surges. IC Role / Device Role / Timing Role: Front-end transient suppressor mounted at connector interface, ahead of precision op-amps and ADC drivers. Use Value: Maintains signal integrity by clamping induced spikes before they saturate input stages, preserving measurement accuracy and avoiding system resets. |
| Telecom DC Power Feeds | Consumer Appliance Motor Control |
Use Scenario: Overvoltage protection on -48 V telecom rectifier outputs feeding remote radio units. IC Role / Device Role / Timing Role: Bidirectional-capable variant not used; SMAJ40AHM3/H serves as unidirectional clamp referenced to negative rail. Use Value: Withstands repetitive 400 W pulses from lightning-induced surges on outdoor cabling while maintaining <1 μA leakage at nominal -48 V. | Use Scenario: Suppressing commutation spikes from brushed DC motors in smart home appliances (e.g., vacuum cleaners, washing machines). IC Role / Device Role / Timing Role: Mounted across motor terminals or H-bridge supply rails to absorb inductive kickback energy. Use Value: Extends MOSFET lifetime by limiting drain-source voltage overshoot to 64.5 V during 40 A turn-off events, reducing avalanche stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40AHE3/H | Same electrical specs; RoHS-compliant but not halogen-free; no AEC-Q101 qualification | Suitable for commercial/industrial use only; not approved for automotive production | Select when halogen content and automotive qualification are not required, and cost optimization is prioritized |
| SMAJ43AHM3/H | Higher VWM (43 V), VBR (47.8–52.8 V), and VC (69.4 V); same package and power rating | Better margin for 42 V nominal systems; slightly higher clamping may risk marginal 48 V ICs | Choose for designs with ≥3 V headroom above nominal rail to improve surge immunity without compromising safety margin |
Compared with SMAJ40AHM3/H, SMAJ40AHE3/H lacks halogen-free and AEC-Q101 compliance, while SMAJ43AHM3/H trades tighter clamping for higher stand-off tolerance - both require validation of layout thermal relief and grounding paths to maintain specified PPPM performance.
Availability
SMAJ40AHM3/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial programmable logic controllers, and telecom power feed applications requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ40AHM3/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 and high-volume manufacturability.
The SMAJ series is engineered for rugged transient suppression in harsh environments - targeting automotive, industrial, and telecom infrastructure where consistent clamping performance and AEC-Q101 validation are mandatory.
FAQ
What is the maximum clamping voltage of SMAJ40AHM3/H under a 10/1000 μs surge?
The SMAJ40AHM3/H exhibits a maximum clamping voltage (VC) of 64.5 V when subjected to its rated peak pulse current of 6.2 A using the standardized 10/1000 μs waveform. This value is measured per JEDEC standards and confirmed in Vishay's datasheet revision 09-Jan-2024, Document Number 88390. The clamping performance directly defines the upper voltage limit imposed on protected circuitry during surge events, making it critical for safeguarding 48 V-rated components. SMAJ40AHM3/H maintains this VC specification across its qualified operating temperature range.
Is SMAJ40AHM3/H qualified for automotive applications?
Yes, SMAJ40AHM3/H is AEC-Q101 qualified, as explicitly stated in the Vishay datasheet under "Mechanical Data" and "Ordering Information." The "HM3" suffix denotes halogen-free, RoHS-compliant construction combined with AEC-Q101 qualification - validated for use in automotive powertrain, body electronics, and ADAS subsystems. This qualification covers stress tests including temperature cycling, high-temperature reverse bias, and unbiased highly accelerated stress testing. SMAJ40AHM3/H is intended for production automotive use, not just evaluation.
What does the "H" in SMAJ40AHM3/H indicate in the ordering code?
The final "H" in SMAJ40AHM3/H specifies the preferred package code for 7-inch diameter plastic tape and reel delivery, containing 1800 units per reel. This is defined in Vishay's Ordering Information table (page 3 of Document Number 88390). The "HM3" base denotes halogen-free and RoHS-compliant construction with AEC-Q101 qualification, while the trailing "/H" confirms the reel size and quantity configuration. SMAJ40AHM3/H is distinct from /I (13-inch reel, 7500 units) and ensures compatibility with standard SMT pick-and-place feeders calibrated for 7″ reels.
How does the thermal resistance of SMAJ40AHM3/H affect PCB layout?
SMAJ40AHM3/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on minimum recommended copper pads (0.2″ × 0.2″ per terminal). To sustain its 3.3 W steady-state power dissipation without exceeding TJ(max) = 150 °C, PCB layout must provide adequate copper area and thermal vias - especially under repeated surge conditions where localized heating occurs. Reducing RθJA via enhanced copper pour lowers junction temperature rise, improving reliability and enabling higher duty-cycle operation. SMAJ40AHM3/H's RθJL of 30 °C/W further emphasizes the need for low-impedance thermal paths to internal ground planes.
Can SMAJ40AHM3/H be used in bidirectional configurations?
No, SMAJ40AHM3/H is a unidirectional TVS diode, as indicated by the "A" (not "CA") suffix and the presence of a cathode band marking. Its electrical characteristics - including forward voltage drop and reverse leakage - are specified only for unidirectional operation. For bidirectional protection, Vishay offers the SMAJ40CA series (e.g., SMAJ40CAHM3/H), which lacks polarity marking and provides symmetrical clamping in both directions. Using SMAJ40AHM3/H in a bidirectional role would result in unintended forward conduction during negative transients, potentially damaging the device or failing to protect the circuit. Always match suffix and marking to application polarity requirements.
SMAJ40AHM3/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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 6.2A
- 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)
SMAJ40AHM3/H FAQ
1.How can I place an order for SMAJ40AHM3/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ40AHM3/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 SMAJ40AHM3/H reliable?
The price and inventory of SMAJ40AHM3/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ40AHM3/H is usually 5 days.
3.What payment methods are accepted for SMAJ40AHM3/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ40AHM3/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ40AHM3/H?
SMAJ40AHM3/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ40AHM3/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 SMAJ40AHM3/H?
For technical support, including SMAJ40AHM3/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ40AHM3/H requirements.
6.How does Aetrix verify that SMAJ40AHM3/H is sourced from the original manufacturer or authorized distributors?
All SMAJ40AHM3/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 SMAJ40AHM3/H meets industry standards.
7.What is the process for return or replacement of SMAJ40AHM3/H?
All SMAJ40AHM3/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ40AHM3/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 SMAJ40AHM3/H part is unused and in its original packaging.
Return procedure for SMAJ40AHM3/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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