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Vishay General Semiconductor - Diodes Division SMAJ78AHE3/61
- Part No.:
- SMAJ78AHE3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78AHE3/61.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,116
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Product details
Overview
SMAJ78AHE3/61 from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 126 V maximum clamping voltage (VC) at 3.2 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power supplies.
For engineers reviewing the SMAJ78AHE3/61 datasheet, SMAJ78AHE3/61 pinout, SMAJ78AHE3/61 application, or SMAJ78AHE3/61 equivalent, key selection criteria include its AEC-Q101 qualification, unidirectional polarity with cathode band marking, 3.2 A IPPM capability at 126 V clamping, and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode operates as a fast-acting shunt protector: under normal conditions it presents high impedance (>1 μA leakage at 78 V), then avalanches within picoseconds when transient voltage exceeds VBR to clamp the line at ≤126 V. Its glass-passivated junction ensures stable breakdown and low incremental surge resistance.
The device is rated for 400 W peak pulse power below 78 V and derates to 300 W above 78 V per Fig. 2; thermal resistance is 120 °C/W junction-to-ambient (RθJA) and 30 °C/W junction-to-lead (RθJL), enabling reliable operation up to +150 °C junction temperature with appropriate PCB copper area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 86.7 V / 95.8 V at IT = 1 mA - defines guaranteed avalanche onset range for design margining |
| VC @ IPPM | 126 V at 3.2 A - clamping voltage during 10/1000 μs surge, directly limiting protected circuit stress |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - peak transient energy absorption capacity per standard waveform |
| ID @ VWM | 1.0 μA - ultra-low leakage preserves signal integrity and battery life in always-on circuits |
| TJ max | +150 °C - enables use in under-hood automotive and high-temperature industrial environments |
| Package | SMA (DO-214AC) - industry-standard SMT footprint compatible with JEDEC MS-013, MSL Level 1 |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, molded plastic case with matte tin-plated leads; polarity indicated by cathode band on unidirectional types.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path) in unidirectional configuration |
| Cathode | Avalanche clamping terminal | Marked with band; connected to protected line (e.g., 78 V rail or signal input) to shunt surges to ground |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HAST, and mechanical shock |
| 400 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 Level 4 surges (4 kV line-earth) without degradation when mounted per spec |
| Glass passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter drift |
| Low profile SMA package | Enables high-density layout and compatibility with standard pick-and-place equipment (0.208" × 0.157") |
| MSL Level 1, 260 °C reflow | Supports lead-free assembly without pre-baking or special handling requirements |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12 V/24 V battery-fed ECUs against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between power rail and chassis ground. Use Value: Clamps transients to ≤126 V, preventing damage to downstream DC-DC converters and microcontrollers rated for 36 V input. |
Use Scenario: Safeguarding analog sensor outputs (e.g., pressure, temperature) from ESD and cable discharge events. IC Role / Device Role / Timing Role: Point-of-entry protection on twisted-pair or coaxial signal lines entering control units. Use Value: Sub-1 ns response limits voltage overshoot to <130 V, preserving 16-bit ADC accuracy and avoiding latch-up in op-amps. |
| Telecom Line Card Surge Protection | Consumer Power Adapter Input Protection |
Use Scenario: Secondary-side protection on PoE-powered network switches and base stations. IC Role / Device Role / Timing Role: Parallel-connected TVS on 48 V bias rails feeding PHY ICs and Ethernet magnetics. Use Value: Absorbs 400 W surges per IEC 61000-4-5 while maintaining <1 μA leakage to avoid standby current penalty. |
Use Scenario: Input-stage transient suppression in universal-input AC/DC adapters (90–264 VAC). IC Role / Device Role / Timing Role: Post-bridge rectifier clamping device on bulk capacitor node. Use Value: Limits surge-induced overvoltage to 126 V, protecting primary-side controllers and optocouplers rated for 100 V isolation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A-E3/61 | Commercial-grade version; lacks AEC-Q101 qualification and automotive traceability | Acceptable for non-automotive industrial or consumer use where qualification is not mandated | Select SMAJ78AHE3/61 when automotive compliance, extended temperature validation, or PPAP documentation is required |
| SMBJ78AHE3/61 | Same electrical specs but SMB (DO-214AA) package - 25 % larger footprint, 50 % higher RθJA (150 °C/W) | Better suited for lower-power or less thermally constrained layouts where board space permits | Choose SMAJ78AHE3/61 for space-constrained designs needing identical performance in smaller SMA footprint |
Compared with SMAJ78A-E3/61, the HE3 suffix adds AEC-Q101 qualification and automotive traceability; compared with SMBJ78AHE3/61, the SMAJ78AHE3/61 delivers equal surge capability in 30 % less board area and 20 % lower thermal resistance.
Availability
SMAJ78AHE3/61 is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O cards, and telecom power supply designs requiring stable component supply with full AEC-Q101 compliance and traceable sourcing.
Supply support for SMAJ78AHE3/61 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 application-specific optimization.
The SMAJ series targets robust, surface-mount transient suppression for automotive, industrial, and telecom systems where compact size, high surge rating, and qualification-grade consistency are mandatory.
FAQ
What is the clamping voltage of SMAJ78AHE3/61 at its rated peak pulse current?
The SMAJ78AHE3/61 has a maximum clamping voltage (VC) of 126 V at its specified peak pulse current (IPPM) of 3.2 A, measured using the standardized 10/1000 μs double-exponential waveform. This value ensures protected circuits experience no more than 126 V during surge events, making SMAJ78AHE3/61 suitable for safeguarding 100 V-rated components on 78 V rails.
Is SMAJ78AHE3/61 qualified for automotive applications?
Yes, SMAJ78AHE3/61 is AEC-Q101 qualified, meaning it has passed rigorous stress tests including temperature cycling, highly accelerated stress testing (HAST), and mechanical shock - specifically validated for under-hood and chassis-mounted automotive electronics. The "HE3" suffix explicitly denotes this automotive-grade qualification, distinguishing it from commercial variants like SMAJ78A-E3/61.
What does the "HE3" suffix indicate in SMAJ78AHE3/61?
The "HE3" suffix in SMAJ78AHE3/61 signifies RoHS-compliant construction with AEC-Q101 qualification and automotive traceability - including full PPAP documentation, lot-level test reports, and extended reliability validation. It also confirms compliance with JESD201 Class 2 whisker resistance and J-STD-020 MSL Level 1 reflow profile (peak 260 °C).
How does the SMA package of SMAJ78AHE3/61 compare thermally to larger packages like SMB?
The SMA (DO-214AC) package of SMAJ78AHE3/61 offers a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W, which is 20 % lower than the SMB (DO-214AA) variant's 150 °C/W. This allows SMAJ78AHE3/61 to sustain higher surge repetition rates or operate at elevated ambient temperatures without exceeding its +150 °C maximum junction limit when mounted on 5.0 mm × 5.0 mm copper pads.
Can SMAJ78AHE3/61 be used in bidirectional configurations?
No, SMAJ78AHE3/61 is a unidirectional TVS diode, identifiable by its cathode band marking. For bidirectional protection, Vishay offers the SMAJ78CAHE3/61 variant - which shares the same VWM (78 V) and clamping performance but conducts symmetrically in both polarities. Using SMAJ78AHE3/61 in reverse-biased AC applications risks permanent failure due to forward conduction during negative half-cycles.
SMAJ78AHE3/61 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):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ78AHE3/61 FAQ
1.How can I place an order for SMAJ78AHE3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78AHE3/61 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 SMAJ78AHE3/61 reliable?
The price and inventory of SMAJ78AHE3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78AHE3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ78AHE3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78AHE3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78AHE3/61?
SMAJ78AHE3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78AHE3/61 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 SMAJ78AHE3/61?
For technical support, including SMAJ78AHE3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78AHE3/61 requirements.
6.How does Aetrix verify that SMAJ78AHE3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ78AHE3/61 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 SMAJ78AHE3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ78AHE3/61?
All SMAJ78AHE3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78AHE3/61, 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 SMAJ78AHE3/61 part is unused and in its original packaging.
Return procedure for SMAJ78AHE3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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