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Vishay General Semiconductor - Diodes Division SMAJ78CAHE3/5A
- Part No.:
- SMAJ78CAHE3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78CAHE3/5A.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,628
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Product details
Overview
SMAJ78CAHE3/5A from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection on signal and power lines. It features a 78 V standoff voltage (VWM), 86.7–95.8 V breakdown range (VBR), 126 V clamping voltage (VC) at 3.2 A peak pulse current (IPPM), and 400 W peak pulse power (PPPM) with 10/1000 μs waveform - used to safeguard MOSFETs, ICs, and sensor interfaces against ESD and inductive switching transients in automotive and industrial systems.
For engineers reviewing the SMAJ78CAHE3/5A datasheet, SMAJ78CAHE3/5A pinout, SMAJ78CAHE3/5A application, or SMAJ78CAHE3/5A equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, 150 °C max junction temperature, low incremental surge resistance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, delivering identical clamping behavior during positive and negative transients - critical for protecting AC-coupled or floating signal paths. Its glass-passivated junction ensures stable leakage (<1.0 μA at VWM) and fast response time (<1.0 ps), while the SMA package supports high thermal dissipation via low RθJL (30 °C/W).
The device complies with ANSI/IEEE C62.35 surge standards and is rated for 400 W peak pulse power up to 78 V, derating to 300 W above that threshold. It meets MSL Level 1 per J-STD-020 and is qualified to AEC-Q101 for automotive under-hood applications.
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 1 mA - guaranteed breakdown onset window for reliable trigger margin |
| VC @ IPPM | 126 V at 3.2 A - clamped voltage during 10/1000 μs surge, limiting stress on downstream components |
| PPPM | 400 W - peak transient energy absorption capacity with standard lightning/surge waveform |
| ID @ VWM | ≤1.0 μA - ultra-low leakage preserves signal integrity and battery life in always-on circuits |
| TJ max | +150 °C - enables operation in under-hood automotive environments and industrial enclosures |
| Package | SMA (DO-214AC) - surface-mount footprint compatible with high-volume reflow assembly |
Pinout & Package
Two-terminal bidirectional device in SMA (DO-214AC) package; no polarity marking required. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102, with MSL Level 1 rating and 260 °C peak reflow profile.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (negative half-cycle) | Conducts surge current during negative voltage excursions; symmetrical with cathode |
| Cathode | Transient current entry (positive half-cycle) | Conducts surge current during positive voltage excursions; symmetrical with anode |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood use including engine control units and body electronics |
| 400 W peak pulse power | Withstands IEC 61000-4-5 surge events up to 4 kV (line-to-earth) without degradation |
| Low clamping ratio (VC/VBR ≈ 1.33) | Minimizes overvoltage overshoot during fast transients, enhancing system-level reliability |
| MSL Level 1 moisture sensitivity | Enables unlimited floor life and eliminates bake requirements prior to reflow soldering |
| Glass passivated junction | Ensures long-term stability of leakage current and breakdown voltage over temperature and time |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting LIN bus or 12 V supply rails in vehicle body control modules from load dump and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional clamping element placed between power rail and ground to shunt surge energy away from MCU and transceivers. Use Value: Maintains <1.0 μA leakage at 78 V to avoid parasitic drain while clamping 126 V transients - preserving CAN/LIN signal integrity and meeting ISO 16750-2 pulse 5a requirements. | Use Scenario: Safeguarding analog outputs of pressure or temperature sensors in factory automation PLCs exposed to relay coil kickback. IC Role / Device Role / Timing Role: Low-capacitance TVS placed across sensor output and ground to absorb 10/1000 μs inductive spikes without distorting mV-level signals. Use Value: 126 V clamping voltage limits stress on op-amp input stages; SMA package allows placement within 2 mm of connector entry point for optimal PCB layout. |
| Consumer USB Port ESD Protection | Telecom DSL Line Surge Suppression |
Use Scenario: Secondary-level ESD protection on USB 2.0 VBUS and D+/D− lines in set-top boxes and smart displays. IC Role / Device Role / Timing Role: Bidirectional TVS deployed after primary polymer PTC to handle multi-kV HBM/IEC 61000-4-2 events without latch-up. Use Value: 86.7–95.8 V VBR ensures no conduction during normal 5 V operation; 126 V VC prevents damage to USB PHY transceivers during ±8 kV contact discharge. | Use Scenario: Front-end surge suppression on twisted-pair DSL lines entering residential gateways subjected to lightning-induced surges. IC Role / Device Role / Timing Role: Symmetrical clamping device bridging tip/ring lines to ground, absorbing common-mode transients per ITU-T K.21 basic level. Use Value: 400 W PPPM rating handles 10/1000 μs surges up to 10 A; bidirectional symmetry avoids polarity-dependent failure modes in AC-coupled telecom circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78CA-M3/5A | Halogen-free, RoHS-compliant variant; identical electrical specs and AEC-Q101 qualification | No functional difference; selected when halogen-free compliance is mandated by OEM sustainability policy | Choose for green manufacturing programs requiring IEC 61249-2-21 compliance |
| SMBJ78CAHE3/5A | Same VWM/VBR/VC ratings but in larger SMB (DO-214AA) package; 600 W PPPM rating | Higher power handling supports longer surge durations or higher repetition rates; requires larger PCB area | Choose when system-level testing reveals 400 W insufficient for worst-case lightning surges |
Compared with SMAJ78CAHE3/5A, the SMAJ78CA-M3/5A offers identical protection performance with halogen-free materials, while SMBJ78CAHE3/5A trades compact size for +50 % pulse power headroom - enabling design flexibility where layout space permits higher robustness.
Availability
SMAJ78CAHE3/5A is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor nodes, consumer USB power delivery systems, and telecom line interface cards requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ78CAHE3/5A 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, automotive qualification, and high-volume manufacturability.
The SMAJ series is engineered for cost-effective, high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where AEC-Q101 validation and consistent clamping performance are mandatory.
FAQ
What does the "HE3" suffix indicate in SMAJ78CAHE3/5A?
The HE3 suffix in SMAJ78CAHE3/5A denotes RoHS-compliant construction with AEC-Q101 qualification for automotive applications. It confirms the device meets stringent reliability testing including temperature cycling, humidity bias, and mechanical shock - validated per JESD22-A108 and JESD22-A110. This makes SMAJ78CAHE3/5A suitable for under-hood and chassis-mounted electronics where long-term stability under thermal stress is critical.
Is SMAJ78CAHE3/5A unidirectional or bidirectional?
SMAJ78CAHE3/5A is a bidirectional transient voltage suppressor, as indicated by the "CA" suffix. It provides symmetrical clamping for both positive and negative voltage transients, with identical VBR (86.7–95.8 V), VC (126 V), and IPPM (3.2 A) characteristics in either polarity. This eliminates polarity concerns during PCB layout and supports AC-coupled or floating signal lines - unlike unidirectional variants (e.g., SMAJ78A) which require correct cathode orientation.
What is the maximum clamping voltage of SMAJ78CAHE3/5A and at what current is it specified?
The maximum clamping voltage (VC) of SMAJ78CAHE3/5A is 126 V, measured at a peak pulse current (IPPM) of 3.2 A using the standardized 10/1000 μs double-exponential waveform. This value represents the upper limit of voltage seen by protected circuitry during a surge event and is guaranteed across the full operating temperature range (–55 °C to +150 °C), ensuring predictable protection margins in automotive and industrial environments.
Does SMAJ78CAHE3/5A meet automotive qualification standards?
Yes, SMAJ78CAHE3/5A is AEC-Q101 qualified, confirming its suitability for automotive applications including engine control, body electronics, and infotainment systems. The qualification covers stress tests such as high-temperature operating life (HTOL), temperature cycling, and electrostatic discharge (HBM/MM). This certification is explicitly stated in the Vishay datasheet revision 09-Jan-2024 (Document Number: 88390) and applies to all HE3-suffixed SMAJ parts.
What is the thermal resistance and power derating behavior of SMAJ78CAHE3/5A?
SMAJ78CAHE3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W on standard 0.2" × 0.2" copper pads, and junction-to-lead resistance (RθJL) of 30 °C/W. Its 400 W peak pulse power rating applies only at TA = 25 °C and derates linearly above that temperature - dropping to ~300 W at 78 V and further decreasing per Figure 2 in the datasheet. Continuous power dissipation (PD) is limited to 3.3 W, requiring careful thermal management in sustained surge scenarios.
SMAJ78CAHE3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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)
SMAJ78CAHE3/5A FAQ
1.How can I place an order for SMAJ78CAHE3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78CAHE3/5A 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 SMAJ78CAHE3/5A reliable?
The price and inventory of SMAJ78CAHE3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78CAHE3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ78CAHE3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78CAHE3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78CAHE3/5A?
SMAJ78CAHE3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78CAHE3/5A 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 SMAJ78CAHE3/5A?
For technical support, including SMAJ78CAHE3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78CAHE3/5A requirements.
6.How does Aetrix verify that SMAJ78CAHE3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ78CAHE3/5A 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 SMAJ78CAHE3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ78CAHE3/5A?
All SMAJ78CAHE3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78CAHE3/5A, 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 SMAJ78CAHE3/5A part is unused and in its original packaging.
Return procedure for SMAJ78CAHE3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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