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Vishay General Semiconductor - Diodes Division SMAJ51A-E3/5A
- Part No.:
- SMAJ51A-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51A-E3/5A.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,440
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Product details
Overview
SMAJ51A-E3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for primary overvoltage protection of DC power rails and signal lines. It features a 51 V standoff voltage (VWM), 56.7–62.7 V breakdown range at 1 mA, 82.4 V maximum clamping voltage at 4.9 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed in automotive infotainment power supplies, industrial sensor I/O protection, and telecom interface circuits.
For engineers reviewing the SMAJ51A-E3/5A datasheet, SMAJ51A-E3/5A pinout, SMAJ51A-E3/5A application, or SMAJ51A-E3/5A equivalent, key selection criteria include clamping performance under 4.9 A surge, thermal resistance (RθJA = 120 °C/W), unidirectional polarity marking, RoHS-compliant matte tin plating, and compatibility with automated SMT placement on standard SMA (DO-214AC) footprints.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: when transient voltage exceeds VBR, it avalanches into low-impedance conduction to divert surge current away from downstream ICs. Its glass-passivated junction ensures stable breakdown characteristics and fast response (<1 ps), while the SMA package supports high thermal dissipation via copper pad mounting per JESD22-B102 solderability standards.
The device is rated for -55 °C to +150 °C operating junction temperature, meets MSL Level 1 per J-STD-020 (peak reflow 260 °C), and exhibits 0.104 %/°C temperature coefficient of VBR. It delivers 3.3 W steady-state power dissipation on infinite heatsink at 50 °C ambient and withstands 40 A non-repetitive forward surge (8.3 ms half-sine).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous reverse operating voltage before leakage exceeds 1 μA; defines safe DC rail margin. |
| VBR (min/max) | 56.7 V / 62.7 V at 1 mA - Confirmed avalanche onset range; ensures reliable triggering above normal operating voltage. |
| VC @ IPPM | 82.4 V at 4.9 A - Clamped voltage during 10/1000 μs surge; determines protected circuit's maximum transient exposure. |
| PPPM | 400 W - Peak pulse power handling capability; enables robust protection against IEC 61000-4-5 Level 4 surges. |
| RθJA | 120 °C/W - Junction-to-ambient thermal resistance; requires ≥5.0 mm × 5.0 mm copper pads for full 400 W rating. |
| IFSM | 40 A - Single half-sine surge current rating; validates survivability against motor-switching transients. |
| TJmax | +150 °C - Maximum junction temperature; supports operation in under-hood automotive and industrial enclosures. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile plastic case with matte tin-plated leads. Cathode indicated by band; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Connected to protected line; conducts surge current to ground when VIN > VBR. |
| Anode (unbanded end) | Reference node | Typically tied to system ground or lower-potential rail; completes shunt path during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables compliance with IEC 61000-4-5 surge immunity up to 4 kV (line-earth) in compact SMA footprint. |
| Glass passivated junction | Ensures stable VBR tolerance and long-term reliability under repeated surge stress without parameter drift. |
| MSL Level 1 moisture sensitivity | Allows direct placement without baking; compatible with standard lead-free reflow profiles up to 260 °C peak. |
| AEC-Q101 qualified variant available | HE3/HM3 suffix versions meet automotive qualification for engine control, ADAS, and body electronics applications. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ESD, inductive kick), improving protection margin. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: 12 V battery-supplied microcontroller power input in vehicle telematics modules exposed to load-dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between VIN and GND, clamping surges before LDO regulator input. Use Value: Limits transient voltage to ≤82.4 V, preventing damage to 3.3 V/5 V logic ICs and enabling compliance with ISO 7637-2 Pulse 5a. |
Use Scenario: Analog output line (4–20 mA) from pressure sensor in factory automation PLC I/O module. IC Role / Device Role / Timing Role: TVS connected across signal and return lines to suppress EFT bursts and cable-coupled lightning-induced spikes. Use Value: Clamps transients within <1 ns, preserving signal integrity and avoiding false triggering of ADC front-end stages. |
| Telecom Interface Surge Protection | Consumer USB Port ESD Protection |
Use Scenario: RS-485 transceiver bus lines in networked security cameras installed outdoors. IC Role / Device Role / Timing Role: Bidirectional-capable design (via SMAJ51CA variant) used in differential pair protection; SMAJ51A-E3/5A applied for single-ended bias rail clamp. Use Value: Absorbs 400 W surges from induced lightning energy while maintaining <100 pF junction capacitance to avoid signal distortion at 10 Mbps. |
Use Scenario: VBUS line in USB 2.0 host port of smart speaker, subject to user-handling ESD events. IC Role / Device Role / Timing Role: Primary shunt protector upstream of USB switch IC, triggered before internal ESD structures activate. Use Value: Clamps ±15 kV contact discharge to <82.4 V within picoseconds, preventing latch-up or gate oxide rupture in USB PHY. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51A-M3/5A | Halogen-free, RoHS-compliant variant with identical electrical specs and SMA package. | No difference in circuit function or layout; selected where halogen-free material compliance is mandated. | Choose for environmental compliance programs requiring halogen-free bill-of-materials. |
| SMAJ51AHE3_A/I | AEC-Q101 qualified version with same VWM, VBR, and VC; validated for automotive temperature cycling and humidity testing. | Required for under-hood, ADAS, or infotainment systems needing automotive-grade reliability certification. | Specify for automotive OEM designs requiring documented AEC-Q101 qualification evidence. |
Compared with SMAJ51A-E3/5A, the M3/5A offers identical protection performance with halogen-free molding compound, while the HE3_A/I adds AEC-Q101 qualification for automotive use - neither is pin-compatible with bidirectional variants like SMAJ51CA, and all require the same SMA footprint and cathode orientation.
Availability
SMAJ51A-E3/5A is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and telecom surge suppression requiring stable component supply, consistent RoHS compliance, and verified 13" tape-and-reel logistics support.
Supply support for SMAJ51A-E3/5A 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 is engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where robustness against inductive switching, ESD, and lightning-induced surges is critical.
FAQ
What is the maximum clamping voltage of the SMAJ51A-E3/5A under a 10/1000 μs surge?
The SMAJ51A-E3/5A 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 ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ51A-E3/5A maintains this clamping performance across its specified operating temperature range.
Is the SMAJ51A-E3/5A suitable for automotive applications?
The SMAJ51A-E3/5A itself is commercial-grade and RoHS-compliant, but not AEC-Q101 qualified. For automotive use, Vishay offers the SMAJ51AHE3_A/I variant - identical in electrical parameters and SMA package, yet fully qualified to AEC-Q101. Engineers must select SMAJ51AHE3_A/I, not SMAJ51A-E3/5A, for under-hood or safety-critical automotive subsystems requiring certified reliability.
What is the thermal resistance and recommended PCB layout for full 400 W rating of the SMAJ51A-E3/5A?
The SMAJ51A-E3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W. To achieve its full 400 W peak pulse power rating, Vishay specifies mounting on minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. Reducing pad area derates power handling - the SMAJ51A-E3/5A must be placed with cathode alignment and soldered per J-STD-002 to ensure thermal and mechanical integrity.
How does the SMAJ51A-E3/5A differ from the bidirectional SMAJ51CA?
The SMAJ51A-E3/5A is unidirectional, with polarity marked by a cathode band and intended for DC rail protection where reverse voltage is blocked. In contrast, SMAJ51CA is bidirectional, has no polarity marking, and protects AC or differential lines symmetrically. Their VWM (51 V), VBR, and VC values match, but they are not interchangeable without circuit redesign - SMAJ51A-E3/5A cannot replace SMAJ51CA in AC-coupled paths.
What packaging format is supplied for the SMAJ51A-E3/5A?
The SMAJ51A-E3/5A is supplied in 13" diameter plastic tape-and-reel format with a base quantity of 7500 units per reel (ordering code suffix /5A). The tape conforms to EIA-481 standards, and the device is oriented with cathode band facing a defined direction for automated pick-and-place. Reel packaging ensures moisture-sensitive level (MSL) 1 integrity without baking prior to SMT assembly.
SMAJ51A-E3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ51A-E3/5A FAQ
1.How can I place an order for SMAJ51A-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51A-E3/5A 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 SMAJ51A-E3/5A reliable?
The price and inventory of SMAJ51A-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51A-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ51A-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51A-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51A-E3/5A?
SMAJ51A-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51A-E3/5A 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 SMAJ51A-E3/5A?
For technical support, including SMAJ51A-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51A-E3/5A requirements.
6.How does Aetrix verify that SMAJ51A-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ51A-E3/5A 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 SMAJ51A-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ51A-E3/5A?
All SMAJ51A-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51A-E3/5A, 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 SMAJ51A-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ51A-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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