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Vishay General Semiconductor - Diodes Division SMAJ40CAHM3/I
- Part No.:
- SMAJ40CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ40CAHM3/I.pdf
- Description:
- TVS DIODE 40VWM 64.5VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,920
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Product details
Overview
SMAJ40CAHM3/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 40 V standoff 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 rating with 10/1000 μs waveform - ideal for safeguarding MOSFETs, ICs, and sensor signal lines against inductive switching transients and ESD events.
For engineers reviewing the SMAJ40CAHM3/I datasheet, SMAJ40CAHM3/I pinout, SMAJ40CAHM3/I application, or SMAJ40CAHM3/I equivalent, key selection criteria include its bidirectional polarity, AEC-Q101 qualification (HM3 suffix), halogen-free RoHS compliance, MSL Level 1 moisture sensitivity, and compatibility with automated SMT placement on consumer, industrial, and automotive PCBs.
Technical Context
This TVS diode operates as a voltage-clamping device that remains high-impedance below VWM = 40 V and rapidly transitions to low-impedance conduction above VBR (min 44.4 V), limiting transient energy to safe levels. Its bidirectional architecture enables symmetrical clamping in both polarities without external polarity management.
It delivers 6.2 A peak pulse current (IPPM) under 10/1000 μs surge conditions while maintaining VC ≤ 64.5 V, with thermal resistance RθJA = 120 °C/W and RθJL = 30 °C/W - enabling reliable operation up to TJ = 150 °C when mounted on standard 5.0 mm × 5.0 mm copper pads per terminal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before significant leakage; defines system's normal operating margin. |
| VBR (min/max) | 44.4 V / 49.1 V at IT = 1 mA - Confirmed breakdown threshold range; ensures predictable turn-on during overvoltage events. |
| VC @ IPPM | 64.5 V at 6.2 A - Clamped voltage during 10/1000 μs surge; determines maximum stress imposed on protected downstream circuitry. |
| PPPM | 400 W - Peak pulse power handling capability; supports repetitive 0.01% duty cycle surges without degradation. |
| IFSM | 40 A - Non-repetitive forward surge current rating (8.3 ms half-sine); validates robustness against short-duration inrush. |
| TJ max. | 150 °C - Maximum junction temperature; sets thermal design limits for PCB pad layout and ambient derating. |
| Package | SMA (DO-214AC) - Surface-mount outline with 5.28 mm × 4.50 mm footprint; compatible with J-STD-020 reflow profiles (peak 260 °C). |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; bidirectional configuration has no polarity marking - terminals are electrically symmetric.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Bidirectional transient path | Either terminal serves as input/output for clamping; no cathode band marking; enables placement flexibility on differential or AC-coupled lines. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for under-hood and ADAS applications. |
| Halogen-free & RoHS-compliant (HM3) | Meets IEC 61249-2-21 and JEDEC J-STD-20E requirements; eliminates brominated flame retardants without compromising UL 94 V-0 flammability rating. |
| 400 W peak pulse power (10/1000 μs) | Supports high-energy transients common in motor drives and power supply inputs while maintaining sub-65 V clamping performance. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (<1 ns response time), improving protection margin for high-speed digital interfaces. |
| MSL Level 1 (260 °C peak) | Enables single-pass reflow without baking; reduces manufacturing complexity and cost in high-volume SMT assembly. |
Applications
| Automotive Sensor Protection | Industrial Motor Drive Inputs |
|---|---|
|
Use Scenario: Protecting CAN/LIN bus transceivers and analog sensor front-ends (e.g., pressure, temperature) from load-dump and jump-start transients in 12 V systems. IC Role / Device Role / Timing Role: Bidirectional clamping element placed across signal/power rails to limit voltage excursions to <65 V during ISO 7637-2 Pulse 5a events. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V microcontrollers and analog signal chains by holding rail voltage within safe operating area during 100 V/500 ms surges. |
Use Scenario: Safeguarding gate drivers and microcontroller I/O pins in variable-frequency drives subjected to inductive kickback from relay coils and contactors. IC Role / Device Role / Timing Role: Fast-response shunt protector installed at power entry and control signal interfaces to clamp 600 V/10 μs spikes generated by IGBT switching. Use Value: Enables use of lower-voltage-rated logic components (e.g., 5 V GPIOs) without additional isolation, reducing BOM cost and board space. |
| Consumer Power Adapter Outputs | Telecom Line Interface Protection |
|
Use Scenario: Secondary-side overvoltage suppression in USB-C PD adapters and AC/DC wall adapters exposed to lightning-induced surges on output cables. IC Role / Device Role / Timing Role: Standoff-rated TVS placed between +VOUT and GND to absorb 400 W pulses while maintaining tight regulation under normal operation. Use Value: Meets UL 62368-1 transient immunity requirements without requiring bulkier MOVs or complex active crowbar circuits. |
Use Scenario: Primary protection for Ethernet PHYs, DSL line cards, and PoE injectors connected to unshielded outdoor cabling vulnerable to induced lightning surges. IC Role / Device Role / Timing Role: First-stage clamping device on RJ-45 interface lines, coordinated with secondary GDT or polymer PTC for multi-level protection. Use Value: Limits coupled transients to <65 V before reaching 100BASE-TX transformers, preserving signal integrity and preventing PHY reset or damage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40CAHE3/I | Same electrical specs but RoHS-compliant commercial grade (no halogen-free certification); not AEC-Q101 qualified. | Limited to non-automotive industrial or consumer applications where halogen content and automotive qualification are not mandated. | Select when cost sensitivity outweighs halogen-free or automotive qualification requirements. |
| SMBJ40CAHM3/I | Same VWM/VC ratings but higher 600 W PPPM; larger SMB (DO-214AA) package (5.28 mm × 4.57 mm vs. SMA's 5.28 mm × 4.50 mm). | Better suited for higher-energy surge environments (e.g., mains-connected equipment), but requires PCB layout revision due to larger footprint and lead spacing. | Choose when system-level surge testing exceeds IEC 61000-4-5 Level 4 and existing SMA layout cannot be modified. |
Compared with SMAJ40CAHM3/I, SMAJ40CAHE3/I offers identical clamping performance at lower cost but lacks halogen-free and automotive qualification, while SMBJ40CAHM3/I provides 50% higher surge power handling in a physically larger package - requiring layout changes but enabling more demanding industrial surge standards.
Availability
SMAJ40CAHM3/I is available at Aetrix Electronics and suitable for automotive sensor modules, industrial motor controllers, consumer power adapters, and telecom line interface designs requiring stable component supply with guaranteed halogen-free and AEC-Q101-compliant sourcing.
Supply support for SMAJ40CAHM3/I 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 optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where consistent clamping performance and long-term stability under thermal cycling are critical.
FAQ
What is the clamping voltage of SMAJ40CAHM3/I at its rated peak pulse current?
The SMAJ40CAHM3/I exhibits a maximum clamping voltage (VC) of 64.5 V when subjected to its rated 6.2 A peak pulse current (IPPM) under the standardized 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that protected circuitry downstream will not experience voltages exceeding 64.5 V during such transient events - a critical parameter for ensuring compatibility with 3.3 V, 5 V, or 12 V logic and analog components. The SMAJ40CAHM3/I maintains this clamping performance across its full operating temperature range.
Is SMAJ40CAHM3/I suitable for automotive applications?
Yes, SMAJ40CAHM3/I is explicitly qualified to AEC-Q101 standards, as confirmed by Vishay's ordering code suffix "HM3" (halogen-free, RoHS-compliant, and AEC-Q101 qualified). It undergoes rigorous stress testing including temperature cycling, high-temperature reverse bias, and ESD verification - making it appropriate for under-hood, body control, and ADAS subsystems. Its bidirectional configuration and 40 V standoff rating align with 12 V automotive battery rail protection requirements, and its MSL Level 1 rating supports direct placement in automotive SMT lines without pre-baking.
How does the HM3 suffix differ from the HE3 suffix in SMAJ40CA variants?
The HM3 suffix on SMAJ40CAHM3/I denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction, whereas the HE3 suffix (e.g., SMAJ40CAHE3/I) indicates RoHS-compliant and AEC-Q101-qualified but not halogen-free. Both meet automotive reliability standards, but HM3 complies with stricter environmental mandates such as JEDEC J-STD-20E and IEC 61249-2-21 for bromine/chlorine content. This distinction matters for Tier 1 suppliers requiring full material declarations and for markets enforcing halogen-free policies like certain EU automotive programs.
What is the thermal resistance of SMAJ40CAHM3/I, and how does it affect PCB layout?
SMAJ40CAHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and junction-to-lead resistance (RθJL) of 30 °C/W when mounted on the recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. These values mean that at 3.3 W steady-state power dissipation (PD), junction temperature rise could reach ~400 °C without adequate copper - underscoring the necessity of proper pad sizing and thermal vias. For reliable operation near TJ = 150 °C, designers must allocate sufficient copper area and avoid narrow traces connecting to the SMAJ40CAHM3/I terminals.
Can SMAJ40CAHM3/I be used in bidirectional signal line protection, such as RS-485 or CAN bus?
Yes, SMAJ40CAHM3/I is specifically designed for bidirectional protection and is commonly deployed on differential buses like RS-485 and CAN. Its symmetrical VBR (44.4–49.1 V) and VC (64.5 V) characteristics ensure equal clamping in both polarities, making it ideal for protecting balanced lines without polarity concerns. When placed across A/B lines or between line and ground, it suppresses common-mode transients up to ±64.5 V while maintaining signal integrity - provided layout minimizes parasitic inductance and follows manufacturer-recommended pad geometry for optimal response time.
SMAJ40CAHM3/I 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:
- -
- Bidirectional Channels:
- 1
- 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)
SMAJ40CAHM3/I FAQ
1.How can I place an order for SMAJ40CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ40CAHM3/I 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 SMAJ40CAHM3/I reliable?
The price and inventory of SMAJ40CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ40CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ40CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ40CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ40CAHM3/I?
SMAJ40CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ40CAHM3/I 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 SMAJ40CAHM3/I?
For technical support, including SMAJ40CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ40CAHM3/I requirements.
6.How does Aetrix verify that SMAJ40CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ40CAHM3/I 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 SMAJ40CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ40CAHM3/I?
All SMAJ40CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ40CAHM3/I, 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 SMAJ40CAHM3/I part is unused and in its original packaging.
Return procedure for SMAJ40CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ40CAHM3/I Tags
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