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Vishay General Semiconductor - Diodes Division SMAJ51CAHM3/I
- Part No.:
- SMAJ51CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51CAHM3/I.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,405
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Product details
Overview
SMAJ51CAHM3/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 51 V stand-off voltage (VWM), 56.7–62.7 V breakdown voltage (VBR) at 1 mA, 82.4 V maximum clamping voltage (VC) at 4.9 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ51CAHM3/I datasheet, SMAJ51CAHM3/I pinout, SMAJ51CAHM3/I application, or SMAJ51CAHM3/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification (HM3 suffix), halogen-free RoHS compliance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 μA leakage at 51 V), but triggers into low-impedance conduction when transients exceed VBR, limiting downstream voltage to ≤82.4 V. Its glass-passivated junction ensures stable avalanche behavior and fast response (<1 ns).
Rated for -55 °C to +150 °C junction temperature, it delivers 400 W peak pulse power up to 78 V (derated to 300 W above), with thermal resistance RθJA = 120 °C/W and RθJL = 30 °C/W - enabling reliable operation on standard PCB copper without heatsinking in intermittent surge events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - maximum continuous reverse operating voltage before significant leakage begins |
| VBR min/max | 56.7 V / 62.7 V at 1 mA - guaranteed avalanche initiation range defining turn-on threshold |
| VC @ IPPM | 82.4 V at 4.9 A - clamped voltage during full-rated 10/1000 μs surge, limiting stress on protected ICs |
| PPPM | 400 W - peak transient energy absorption capacity with standardized 10/1000 μs waveform |
| ID @ VWM | 1.0 μA - ultra-low reverse leakage ensuring minimal standby power loss and signal integrity |
| TJ max | +150 °C - enables use in under-hood automotive and high-temperature industrial environments |
| Package | SMA (DO-214AC) - surface-mount footprint compatible with JEDEC MS-013, MSL Level 1, 260 °C reflow |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; polarity-unmarked for bidirectional operation; meets UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (during positive half-cycle) | One terminal of symmetrical avalanche junction - conducts when voltage exceeds +VBR |
| Cathode | Transient current entry (during negative half-cycle) | Second terminal of symmetrical junction - conducts when voltage exceeds –VBR; no band marking |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified (HM3 suffix) | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per JESD22 standards |
| Halogen-free & RoHS-compliant | Meets IEC 61249-2-21 and JEDEC J-STD-020 MSL Level 1 requirements for green manufacturing |
| 400 W peak pulse power (≤78 V) | Withstands IEC 61000-4-5 Level 4 surges (4 kV line-earth, 2 kV line-line) without degradation |
| Low clamping ratio (VC/VBR ≈ 1.35) | Minimizes let-through voltage to protect 5 V–36 V logic and analog circuitry downstream |
| Fast response time < 1 ns | Clamps transients before propagation across PCB traces or into IC input stages |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 12 V/24 V supply inputs in engine control units (ECUs) and body controllers against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Shunt-type transient voltage suppressor placed directly at connector entry point before DC-DC converter input. Use Value: Clamps 120 V/200 ms load dump transients to ≤82.4 V, preventing damage to upstream LDOs and microcontrollers. | Use Scenario: Safeguarding analog outputs (4–20 mA, 0–10 V) and digital I/O (CAN, LIN) in factory-floor pressure/temperature sensors. IC Role / Device Role / Timing Role: Bidirectional TVS placed differential-mode across signal pair and common-mode to ground. Use Value: Limits induced lightning surges (IEC 61000-4-5) to safe levels while maintaining <1 μA leakage at 51 V operating bias. |
| Consumer Device USB Port Protection | Telecom Base Station DC Feeder Protection |
Use Scenario: Guarding USB 2.0 data lines and VBUS in portable medical monitors and smart home hubs against ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance bidirectional clamp on D+ and D− lines, with separate device on VBUS. Use Value: Withstands ±15 kV contact ESD (IEC 61000-4-2) without latch-up or parameter shift due to glass-passivated junction. | Use Scenario: Protecting -48 V DC power feeds in 4G/5G remote radio units exposed to induced surges from nearby lightning strikes. IC Role / Device Role / Timing Role: Primary shunt protector mounted at outdoor cabinet entry point before DC-DC isolation stage. Use Value: Absorbs 400 W transient bursts while maintaining 51 V standoff to avoid false triggering during nominal -48 V operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51CAHE3/I | Same electrical specs; RoHS-compliant but not halogen-free; lacks AEC-Q101 qualification | Approved for commercial/industrial use only; not certified for automotive under-hood deployment | Select when halogen-free content or automotive qualification is not required and cost optimization is prioritized |
| SMBJ51CAHM3/I | Same VWM/VBR/VC ratings; higher 600 W PPPM rating; larger SMB (DO-214AA) package | Requires PCB layout change; better suited for higher-energy surges where space permits | Choose when system-level surge testing exceeds 400 W and board area allows SMB footprint |
Compared with SMAJ51CAHE3/I, the SMAJ51CAHM3/I adds halogen-free construction and AEC-Q101 validation for automotive use; versus SMBJ51CAHM3/I, it trades 200 W higher pulse power for 30% smaller PCB area and identical mounting process.
Availability
SMAJ51CAHM3/I is available at Aetrix Electronics and suitable for automotive ECU designs, industrial sensor modules, and telecom power feeders requiring stable component supply with long-term lifecycle assurance.
Supply support for SMAJ51CAHM3/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, MOSFETs, and protection devices with emphasis on reliability and application-specific performance.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where robustness against ESD, lightning, and switching surges is mission-critical.
FAQ
What is the clamping voltage of the SMAJ51CAHM3/I under a 10/1000 μs surge?
The SMAJ51CAHM3/I has a maximum clamping voltage (VC) of 82.4 V at 4.9 A peak pulse current (IPPM) under the standardized 10/1000 μs waveform. This value is measured per Figure 1 in Vishay document 88390 and defines the upper voltage limit imposed on protected circuitry during full-rated transient events.
Is the SMAJ51CAHM3/I suitable for automotive applications?
Yes, the SMAJ51CAHM3/I is AEC-Q101 qualified (denoted by the HM3 suffix), making it suitable for automotive applications including engine control units, body electronics, and ADAS sensors. It undergoes rigorous stress testing for temperature cycling, high-temperature reverse bias, and ESD per JESD22 standards.
Does the SMAJ51CAHM3/I have polarity markings on its package?
No, the SMAJ51CAHM3/I is a bidirectional TVS diode and carries no polarity marking - consistent with Vishay's specification that "no marking on bidirectional types." Its symmetrical construction allows installation without orientation concern on PCBs.
What is the thermal resistance from junction to ambient for the SMAJ51CAHM3/I?
The SMAJ51CAHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended pad layout (0.2" × 0.2" copper pads per terminal). This value supports thermal design in compact layouts without forced cooling.
How does the SMAJ51CAHM3/I differ from unidirectional variants like SMAJ51AHM3/I?
The SMAJ51CAHM3/I is bidirectional and clamps transients of either polarity, whereas SMAJ51AHM3/I is unidirectional and only protects against reverse-polarity surges. The 'CA' suffix indicates symmetrical breakdown, enabling use on AC lines or differential signals where polarity reversal occurs.
SMAJ51CAHM3/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):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- 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)
SMAJ51CAHM3/I FAQ
1.How can I place an order for SMAJ51CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51CAHM3/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 SMAJ51CAHM3/I reliable?
The price and inventory of SMAJ51CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ51CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51CAHM3/I?
SMAJ51CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51CAHM3/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 SMAJ51CAHM3/I?
For technical support, including SMAJ51CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51CAHM3/I requirements.
6.How does Aetrix verify that SMAJ51CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ51CAHM3/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 SMAJ51CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ51CAHM3/I?
All SMAJ51CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51CAHM3/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 SMAJ51CAHM3/I part is unused and in its original packaging.
Return procedure for SMAJ51CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ51CAHM3/I Tags
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