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Vishay General Semiconductor - Diodes Division SMAJ78CAHE3_A/I
- Part No.:
- SMAJ78CAHE3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78CAHE3_A/I.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,454
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Product details
Overview
SMAJ78CAHE3_A/I from Vishay General Semiconductor is a bidirectional 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 standoff 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 (IPPM), and 400 W peak pulse power rating (10/1000 μs waveform) - suitable for protecting MOSFETs, ICs, and sensor interfaces in automotive and industrial power rails.
For engineers reviewing the SMAJ78CAHE3_A/I datasheet, SMAJ78CAHE3_A/I pinout, SMAJ78CAHE3_A/I application, or SMAJ78CAHE3_A/I equivalent, this device is evaluated for ESD/surge protection in 12 V–48 V DC systems, AEC-Q101-qualified automotive subsystems, and high-reliability industrial I/O protection where low clamping ratio and fast response (<1 ns) are critical.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, with identical VBR min/max (86.7 V / 95.8 V), VC (126 V), and IPPM (3.2 A) in either direction. Its glass-passivated junction ensures stable leakage (<1 μA at 78 V) and robust surge handling up to 40 A IFSM (8.3 ms half-sine).
Thermally, it exhibits RθJA = 120 °C/W and RθJL = 30 °C/W, enabling operation from –55 °C to +150 °C junction temperature. The HE3 suffix confirms RoHS compliance and AEC-Q101 qualification - required for under-hood automotive modules and engine control units.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before clamping begins; defines safe DC operating margin for 48 V nominal systems. |
| VBR (min/max) | 86.7 V / 95.8 V at 1 mA - guaranteed breakdown threshold range; ensures predictable turn-on during transients without premature conduction. |
| VC @ IPPM | 126 V at 3.2 A - clamped voltage during 10/1000 μs surge; limits downstream stress to <126 V for protected ICs. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - peak transient energy absorption capability; supports repetitive surges at 0.01% duty cycle. |
| ID @ VWM | <1 μA - ultra-low reverse leakage at rated standoff; prevents power loss and thermal drift in battery-backed circuits. |
| TJ max. | +150 °C - enables deployment in high-temperature environments such as automotive power distribution boxes. |
| AEC-Q101 | Qualified - validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD22-A114. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002. No polarity marking - bidirectional symmetry eliminates orientation concerns during automated placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Transient conduction path | Identical terminals handle surge current in either direction; no cathode band marking required for bidirectional operation. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Supports IEC 61000-4-5 Level 4 surge immunity (4 kV line-to-ground) when properly mounted on 5 mm × 5 mm copper pads. |
| Clamping ratio VC/VBR = 1.31 | Low overvoltage margin ensures tight protection window - critical for 75 V-rated MOSFET gate drivers and CAN transceivers. |
| AEC-Q101 qualified (HE3 suffix) | Validated for automotive powertrain and body electronics; includes HTGB, AC-H3TRB, and mechanical shock testing. |
| MSL Level 1 (260 °C peak reflow) | Compatible with standard lead-free SMT reflow profiles without moisture sensitivity concerns or baking requirements. |
| Glass passivated junction | Enhances long-term stability of VBR and leakage under thermal cycling and humidity exposure in industrial enclosures. |
Applications
| Automotive Power Distribution | Industrial Sensor Signal Lines |
|---|---|
Use Scenario: Protection of 48 V battery-fed ECUs against load dump and alternator ripple transients. IC Role / Device Role / Timing Role: Bidirectional clamping element placed between power rail and ground, absorbing >100 V spikes within nanoseconds. Use Value: Limits voltage seen by downstream PMICs and microcontrollers to ≤126 V, preventing latch-up and gate oxide damage. |
Use Scenario: Shielding analog outputs of pressure/temperature sensors from ESD events and cable-induced surges. IC Role / Device Role / Timing Role: Low-capacitance (≈100 pF) shunt protector on 0–5 V or 4–20 mA signal paths. Use Value: Maintains signal integrity with sub-μA leakage at 78 V, avoiding offset errors in precision measurement circuits. |
| Telecom DC Power Feeds | Motor Drive Gate Driver Supplies |
Use Scenario: Safeguarding PoE-powered equipment inputs against lightning-induced surges on 57 V DC feeds. IC Role / Device Role / Timing Role: Primary surge clamp on input stage, coordinated with upstream MOVs and series impedance. Use Value: Fast response (<1 ns) and repeatable clamping enable compliance with ITU-T K.20/21 telecom surge standards. |
Use Scenario: Protecting isolated gate driver supplies (e.g., 15 V bias rails) in BLDC inverters from shoot-through-induced transients. IC Role / Device Role / Timing Role: Localized TVS adjacent to gate driver IC, limiting voltage overshoot during high-di/dt switching. Use Value: Prevents false triggering and gate oxide failure by clamping transients to ≤126 V while sustaining 150 °C junction temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78CA-M3/5A | Halogen-free, RoHS-compliant, commercial grade (non-AEC-Q101); same electrical specs and package. | Lacks automotive qualification; suitable for industrial/commercial power supplies but not under-hood use. | Select when AEC-Q101 is not required and halogen-free compliance is mandated by environmental policy. |
| SMBJ78CAHE3_A/I | Same VWM/VBR/VC ratings but in SMB (DO-214AA) package - 20 % larger footprint and 600 W PPPM rating. | Higher power handling allows longer surge duration support; requires PCB layout change due to larger pad area. | Choose when system-level surge tests exceed 400 W or thermal derating demands lower RθJA than SMA can provide. |
Compared with SMAJ78CAHE3_A/I, the M3 variant trades automotive qualification for halogen-free compliance, while SMBJ78CAHE3_A/I offers higher surge capacity at the cost of board space - making SMAJ78CAHE3_A/I optimal for space-constrained AEC-Q101 designs needing precise 400 W clamping.
Availability
SMAJ78CAHE3_A/I is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interfaces, telecom DC feeds, and motor drive gate driver protection requiring stable component supply and full AEC-Q101 traceability.
Supply support for SMAJ78CAHE3_A/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, and protection devices with emphasis on reliability, efficiency, and automotive-grade validation.
The SMAJ series targets high-volume transient suppression in harsh environments - engineered specifically for AEC-Q101 compliance, low-clamp performance, and seamless SMT integration into automotive and industrial power systems.
FAQ
What is the clamping voltage of SMAJ78CAHE3_A/I at its rated peak pulse current?
The SMAJ78CAHE3_A/I has a maximum clamping voltage (VC) of 126 V at its specified peak pulse current (IPPM) of 3.2 A under a 10/1000 μs waveform. This value is measured per JEDEC standards and guarantees that downstream components will not experience voltages exceeding 126 V during standardized surge events - a key parameter for validating protection margins in 48 V automotive systems.
Is SMAJ78CAHE3_A/I suitable for bidirectional signal line protection?
Yes, SMAJ78CAHE3_A/I is explicitly designed for bidirectional use, as indicated by the "CA" suffix. Its symmetrical VBR and VC characteristics apply equally in both directions, making it ideal for protecting differential or AC-coupled signal lines - such as RS-485 buses or sensor bridge outputs - where polarity reversal or transient direction is unpredictable.
Does SMAJ78CAHE3_A/I meet automotive qualification requirements?
Yes, the "HE3" suffix confirms SMAJ78CAHE3_A/I is RoHS-compliant and AEC-Q101 qualified. It undergoes rigorous stress testing including high-temperature reverse bias (HTRB), temperature cycling, and mechanical shock - fulfilling requirements for deployment in engine control units, body control modules, and other automotive electronic control systems.
What is the thermal resistance of SMAJ78CAHE3_A/I, and how does it affect layout design?
SMAJ78CAHE3_A/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and junction-to-lead (RθJL) of 30 °C/W. To maintain safe operation under repeated surges, PCB layout must use minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal - as specified in the Vishay datasheet - otherwise thermal derating will reduce effective PPPM below 400 W.
How does the leakage current of SMAJ78CAHE3_A/I impact low-power applications?
SMAJ78CAHE3_A/I exhibits ≤1 μA maximum reverse leakage current (ID) at its 78 V standoff voltage (VWM), ensuring negligible quiescent power loss in battery-operated or energy-sensitive systems. This low leakage preserves battery life in always-on automotive modules and avoids signal offset in high-impedance sensor front-ends - verified at TA = 25 °C and applicable across its full operating temperature range.
SMAJ78CAHE3_A/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:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- 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)
SMAJ78CAHE3_A/I FAQ
1.How can I place an order for SMAJ78CAHE3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78CAHE3_A/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 SMAJ78CAHE3_A/I reliable?
The price and inventory of SMAJ78CAHE3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78CAHE3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ78CAHE3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78CAHE3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78CAHE3_A/I?
SMAJ78CAHE3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78CAHE3_A/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 SMAJ78CAHE3_A/I?
For technical support, including SMAJ78CAHE3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78CAHE3_A/I requirements.
6.How does Aetrix verify that SMAJ78CAHE3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ78CAHE3_A/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 SMAJ78CAHE3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ78CAHE3_A/I?
All SMAJ78CAHE3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78CAHE3_A/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 SMAJ78CAHE3_A/I part is unused and in its original packaging.
Return procedure for SMAJ78CAHE3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78CAHE3_A/I Tags
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