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Vishay General Semiconductor - Diodes Division SMAJ51CA-E3/5A
- Part No.:
- SMAJ51CA-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51CA-E3/5A.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,659
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Product details
Overview
SMAJ51CA-E3/5A 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 standoff 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 SMAJ51CA-E3/5A datasheet, SMAJ51CA-E3/5A pinout, SMAJ51CA-E3/5A application, or SMAJ51CA-E3/5A equivalent, key selection criteria include bidirectional clamping symmetry, low clamping ratio (VC/VWM = 1.62), AEC-Q101 qualification eligibility (via HE3/HM3 variants), and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This bidirectional TVS operates symmetrically in both polarities, delivering identical clamping behavior above ±51 V. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 μA at VWM), while the 120 °C/W junction-to-ambient thermal resistance requires careful PCB copper pad design for sustained surge handling.
The device meets UL 497B recognition (QVGQ2) and J-STD-020 MSL Level 1, supporting reflow up to 260 °C. With a 0.01 % duty cycle rating, it handles repetitive transients induced by inductive switching - but derates linearly above 25 °C ambient per Fig. 2, limiting usable IPPM at elevated temperatures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous reverse operating voltage before clamping begins; defines safe operating margin for 48 V nominal systems. |
| VBR (min/max) | 56.7 V / 62.7 V at 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on without premature conduction. |
| VC @ IPPM | 82.4 V at 4.9 A - Clamped voltage during 10/1000 μs surge; limits downstream IC stress to <83 V under worst-case transient. |
| PPPM | 400 W - Peak pulse power dissipation capability; supports high-energy ESD and load-dump events in automotive environments. |
| IPPM | 4.9 A - Peak surge current corresponding to VC; determines minimum trace width and pad area needed for 0.2" × 0.2" copper layout. |
| TJ max. | +150 °C - Maximum junction temperature; enables operation in under-hood automotive locations with proper thermal design. |
| Package | SMA (DO-214AC) - Surface-mount package with 2.54 mm lead pitch; compatible with standard SMT pick-and-place and reflow profiles. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated. Bidirectional configuration has no polarity marking; terminals are symmetrical anode/cathode pairs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (bidirectional) | Surge current path | Both terminals conduct identically during positive or negative transients; no cathode band marking required. |
| Case | Thermal and mechanical interface | Plastic body provides electrical isolation; thermal path relies entirely on soldered leads and PCB copper pads. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping symmetry | Identical VBR, VC, and IPPM in both directions - eliminates need for polarity-aware layout in AC-coupled or floating signal paths. |
| 400 W peak pulse power (10/1000 μs) | Withstands high-energy transients from relay coil decay or alternator load dump without degradation - validated per ISO 7637-2 Pulse 5a. |
| AEC-Q101 qualification path | HE3/HM3 suffix variants meet automotive reliability standards; SMAJ51CA-E3/5A itself is RoHS-compliant commercial grade with same die and construction. |
| Low clamping ratio (VC/VWM = 1.62) | Minimizes overvoltage exposure to protected ICs - critical for 5 V or 3.3 V logic interfacing with 48 V supply domains. |
| MSL Level 1 moisture sensitivity | Zero bake requirement before reflow; supports direct placement from sealed tape-and-reel without dry-pack handling. |
Applications
| Automotive Body Control Module (BCM) | Industrial RS-485 Sensor Interface |
|---|---|
Use Scenario: Protects microcontroller GPIO and CAN transceiver power pins from load-dump transients (ISO 7637-2 Pulse 5a) and jump-start surges in 12 V/48 V hybrid architectures. IC Role / Device Role / Timing Role: Bidirectional TVS placed directly at connector entry point, shunting surge energy to ground before reaching LDOs and communication ICs. Use Value: Clamps 48 V rail to ≤82.4 V during 400 W surge, preventing latch-up or oxide rupture in 5 V tolerant peripherals. |
Use Scenario: Shields differential RS-485 transceivers (e.g., THVD1550) from ESD (IEC 61000-4-2 ±15 kV) and field-induced surges in factory automation cabling. IC Role / Device Role / Timing Role: Placed across A/B bus lines and to ground, providing symmetrical common-mode and differential-mode suppression. Use Value: Maintains signal integrity below 100 Mbps by limiting junction capacitance to <200 pF at 0 V bias - verified in Fig. 4. |
| Consumer Appliance Motor Drive Board | Telecom Power Supply Input Stage |
Use Scenario: Guards MCU reset line and gate driver inputs against inductive kickback from brushed DC motor commutation in washing machine control boards. IC Role / Device Role / Timing Role: Low-leakage (<1 μA) TVS ensures no DC loading on 3.3 V reset circuitry while responding in <1 ns to sub-100 ns spikes. Use Value: Fast response and low VC prevent false resets or unintended FET turn-on during motor switching noise events. |
Use Scenario: Installed at AC-DC converter input to absorb lightning-induced surges (IEC 61000-4-5 2 kV line-earth) before bulk capacitor and PFC controller. IC Role / Device Role / Timing Role: Primary overvoltage clamp in Class II isolated supply, coordinated with MOV and fuse for staged protection. Use Value: 400 W rating allows single-device handling of 10/1000 μs surges up to 2 kV, reducing BOM count versus cascaded TVS-MOV designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51CA-M3/5A | Halogen-free, RoHS-compliant variant with identical electrical specs and SMA package; same thermal and surge performance. | No difference in circuit function or layout; selected only when halogen-free compliance is mandated by end-equipment environmental policy. | Choose SMAJ51CA-M3/5A if IPC-1752A reporting or EU green procurement rules require halogen-free materials. |
| SMAJ51A-E3/5A | Unidirectional version with cathode band marking; same VWM, VBR, VC, and PPPM, but conducts only in reverse direction. | Requires polarity-aware placement; unsuitable for AC or floating signals; used where ground-referenced unidirectional clamping suffices (e.g., 5 V rail to GND). | Select SMAJ51A-E3/5A only when protecting a fixed-polarity rail with known ground reference and no risk of reverse voltage transients. |
Compared with SMAJ51CA-E3/5A, the M3 variant offers identical protection performance with halogen-free molding compound, while the unidirectional SMAJ51A-E3/5A reduces cost slightly but mandates strict polarity alignment and cannot protect bidirectional signal lines.
Availability
SMAJ51CA-E3/5A is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, consumer appliance motor controls, and telecom power supply input stages requiring stable component supply and full traceability.
Supply support for SMAJ51CA-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, rectifiers, MOSFETs, and protection devices with emphasis on reliability, thermal performance, and automotive-grade qualification.
The SMAJ series delivers surface-mount TVS solutions optimized for high-surge immunity in space-constrained applications - engineered specifically for automotive, industrial, and telecom systems demanding repeatable clamping and long-term stability under thermal cycling.
FAQ
What is the clamping voltage of SMAJ51CA-E3/5A at its rated peak pulse current?
The SMAJ51CA-E3/5A has a maximum clamping voltage (VC) of 82.4 V at its specified peak pulse current (IPPM) of 4.9 A, measured using the standardized 10/1000 μs double-exponential waveform. This value is guaranteed across the full operating temperature range and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ51CA-E3/5A maintains this clamping performance bidirectionally due to its symmetrical junction structure.
Is SMAJ51CA-E3/5A suitable for automotive applications requiring AEC-Q101 qualification?
SMAJ51CA-E3/5A itself is a commercial-grade, RoHS-compliant part (E3 suffix) and not AEC-Q101 qualified. However, Vishay offers functionally identical variants - SMAJ51CAHE3_A/I and SMAJ51CAHM3_A/I - which carry full AEC-Q101 qualification and share the same die, package, and electrical specifications. The SMAJ51CA-E3/5A can be used in non-automotive or pre-qualification development phases, but production automotive designs must specify the HE3 or HM3 suffix versions.
How does the bidirectional nature of SMAJ51CA-E3/5A affect PCB layout compared to unidirectional TVS diodes?
The SMAJ51CA-E3/5A has no polarity marking and identical electrical behavior in both directions, eliminating orientation constraints during placement - unlike unidirectional types such as SMAJ51A-E3/5A, which require cathode-band alignment toward the protected rail. This simplifies layout for AC-coupled lines, differential buses (e.g., RS-485), or floating grounds. The SMAJ51CA-E3/5A's symmetrical terminals allow rotation-invariant placement, reducing assembly errors and enabling compact dual-line protection without routing asymmetry.
What is the maximum steady-state power dissipation of SMAJ51CA-E3/5A at 50 °C ambient?
The SMAJ51CA-E3/5A has a maximum steady-state power dissipation (PD) of 3.3 W when mounted on an infinite heatsink at TA = 50 °C. This rating assumes ideal thermal conduction and is significantly lower than its 400 W peak pulse rating, reflecting its intended use for transient - not continuous - overload conditions. In real PCB layouts with finite copper area, derating is required; for example, on 0.2" × 0.2" pads, the practical continuous dissipation drops to ~0.5 W at 50 °C ambient, as inferred from RθJA = 120 °C/W.
Does SMAJ51CA-E3/5A meet any safety certification standards for surge protection devices?
Yes, the SMAJ51CA-E3/5A carries Underwriters Laboratories (UL) Recognition under file E136766 for both unidirectional and bidirectional configurations, compliant with UL 497B for primary protector classification. This certification validates its performance in telecom and industrial surge protection applications, including withstand of repeated 10/1000 μs surges and thermal stability under fault conditions. The SMAJ51CA-E3/5A also meets IEC 61000-4-2 (ESD) and IEC 61000-4-4 (EFT) immunity test levels when applied per recommended layout guidelines.
SMAJ51CA-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:
- -
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ51CA-E3/5A FAQ
1.How can I place an order for SMAJ51CA-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51CA-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 SMAJ51CA-E3/5A reliable?
The price and inventory of SMAJ51CA-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 SMAJ51CA-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ51CA-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51CA-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51CA-E3/5A?
SMAJ51CA-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51CA-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 SMAJ51CA-E3/5A?
For technical support, including SMAJ51CA-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51CA-E3/5A requirements.
6.How does Aetrix verify that SMAJ51CA-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ51CA-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 SMAJ51CA-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ51CA-E3/5A?
All SMAJ51CA-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51CA-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 SMAJ51CA-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ51CA-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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