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Vishay General Semiconductor - Diodes Division SMAJ78CA-E3/61
- Part No.:
- SMAJ78CA-E3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78CA-E3/61.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ78CA-E3/61 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 78 V standoff voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, and clamps transients to ≤126 V at 3.2 A peak pulse current (IPPM) under 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ78CA-E3/61 datasheet, SMAJ78CA-E3/61 pinout, SMAJ78CA-E3/61 application, or SMAJ78CA-E3/61 equivalent, key selection criteria include bidirectional clamping capability, 400 W peak pulse power rating (derated to 300 W above 78 V), AEC-Q101 qualification status, low incremental surge resistance, and compatibility with automated SMT assembly on 0.2" × 0.2" copper pads.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, delivering identical clamping behavior in forward and reverse directions. Its glass-passivated junction enables fast response time (<1 ps) and stable breakdown characteristics over temperature, with a maximum clamping voltage of 126 V at IPPM = 3.2 A and thermal resistance RθJA = 120 °C/W.
The device complies with ANSI/IEEE C62.35 surge standards and meets J-STD-020 MSL Level 1 moisture sensitivity. It supports repetitive surge events at 0.01% duty cycle and withstands 40 A peak forward surge current (IFSM) for unidirectional variants - though SMAJ78CA-E3/61 is bidirectional and thus rated for symmetrical surge handling without polarity dependence.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping initiates; defines safe operating margin for 72–80 V nominal systems. |
| VBR (min/max) | 86.7 V / 95.8 V at IT = 1 mA - Confirmed breakdown range ensures reliable turn-on during transients while avoiding false triggering. |
| VC @ IPPM | ≤126 V at 3.2 A - Clamping voltage limits downstream IC stress during 10/1000 μs surges; critical for protecting 100 V-rated MOSFETs or CAN transceivers. |
| PPPM | 300 W - Peak pulse power rating above 78 V; derated from 400 W per spec note (1), defining energy-handling capacity on PCBs with standard pad layout. |
| IDRM | ≤1.0 μA at VWM - Ultra-low leakage preserves battery life and signal integrity in always-on sensor nodes and automotive standby circuits. |
| TJ max. | +150 °C - Enables operation in under-hood automotive environments and high-temperature industrial enclosures without thermal derating. |
| Package | SMA (DO-214AC) - Surface-mount outline with 5.28 mm × 4.50 mm footprint; compatible with JEDEC-standard reflow profiles and J-STD-002 solderability. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated compound, and no polarity marking for bidirectional configuration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Bidirectional terminal pair | No functional distinction - either lead connects to protected line; enables placement without orientation check during automated assembly. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W / 300 W peak pulse power | Supports IEC 61000-4-5 Level 4 surge immunity (4 kV line-earth) when mounted on 5 mm × 5 mm copper pads. |
| AEC-Q101 qualified (via HE3/HM3 variants) | SMAJ78CA-E3/61 is RoHS-compliant commercial grade; AEC-Q101 version requires HE3 suffix - essential for automotive module qualification. |
| Glass passivated junction | Ensures stable VBR drift <±5% over lifetime and eliminates parameter shift due to humidity or bias stress. |
| MSL Level 1, 260 °C peak reflow | Enables single-pass lead-free reflow without popcorn effect or bond wire damage - validated per J-STD-020. |
| Low clamping ratio (VC/VBR ≈ 1.32) | Minimizes let-through energy compared to Zener-based protectors; improves system-level ESD and surge margin. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Guarding |
|---|---|
Use Scenario: Protecting 12 V/24 V supply inputs in body control modules against load dump and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed between rail and ground, absorbing >300 W surge energy without failure. Use Value: Prevents latch-up or destruction of downstream PMICs and microcontrollers during ISO 7637-2 Pulse 5a events. |
Use Scenario: Shielding analog outputs (e.g., 4–20 mA loops) and digital I/O (CAN, LIN) in factory-floor sensors. IC Role / Device Role / Timing Role: Fast-response shunt protector diverting ESD (IEC 61000-4-2 ±8 kV contact) and burst noise away from precision ADCs. Use Value: Maintains signal fidelity by limiting transient overvoltage to <126 V, preserving 16-bit measurement accuracy under EMC stress. |
| Telecom Interface Surge Suppression | Consumer Device USB/DC Jack Protection |
Use Scenario: Safeguarding Ethernet PHY power pins and data pairs in PoE-powered switches and base stations. IC Role / Device Role / Timing Role: Primary front-end TVS on DC input and secondary clamping on differential data lines. Use Value: Withstands repeated 10/1000 μs surges up to 300 W, meeting GR-1089-CORE telecom immunity requirements. |
Use Scenario: Input-stage protection for wall adapters and USB-C PD ports in smart home hubs and portable audio gear. IC Role / Device Role / Timing Role: Low-leakage (≤1 μA) bidirectional clamp preventing reverse-bias damage during hot-plug and miswiring. Use Value: Eliminates need for separate forward/reverse diodes; reduces BOM count while maintaining <126 V clamping under 3.2 A surge. |
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 | Unidirectional variant; cathode band marked; VF = 3.5 V @ 25 A (not applicable to bidirectional SMAJ78CA-E3/61). | Requires correct polarity placement; unsuitable for AC-coupled or floating signal lines. | Select only when circuit topology enforces fixed polarity and lower forward voltage is needed for crowbar-style protection. |
| SMBJ78CA-E3/52 | Larger SMB (DO-214AA) package; 600 W PPPM; same VWM/VBR specs but higher IPPM (5.0 A) and lower Rsurge. | Occupies 25% more board area; better suited for high-energy surges where SMAJ78CA-E3/61 reaches thermal limit. | Choose when system-level testing reveals insufficient margin with SMAJ78CA-E3/61 under repetitive 10/1000 μs stress. |
Compared with SMAJ78A-E3/61, SMAJ78CA-E3/61 enables polarity-agnostic placement and eliminates risk of reverse-bias misconnection; versus SMBJ78CA-E3/52, it trades peak power headroom for compactness and cost efficiency in space-constrained automotive and IoT designs.
Availability
SMAJ78CA-E3/61 is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, and telecom infrastructure requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ78CA-E3/61 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, rectifiers, MOSFETs, and protection devices with emphasis on reliability, AEC-Q qualification, and high-volume manufacturability.
The SMAJ series targets cost-sensitive, high-reliability transient suppression in automotive, industrial, and communications systems - engineered for rapid response, low clamping, and seamless SMT integration.
FAQ
What is the clamping voltage of SMAJ78CA-E3/61 at its rated peak pulse current?
The SMAJ78CA-E3/61 clamps to a maximum of 126 V at its specified peak pulse current of 3.2 A under the 10/1000 μs waveform. This value is measured per Figure 1 and Table 1 in Vishay's Document Number 88390 and defines the upper voltage limit imposed on protected circuitry during surge events - critical for ensuring downstream components remain within absolute maximum ratings.
Is SMAJ78CA-E3/61 AEC-Q101 qualified?
No, SMAJ78CA-E3/61 is the commercial-grade RoHS-compliant variant with E3 suffix. AEC-Q101 qualification is available only in the HE3 or HM3 versions (e.g., SMAJ78CAHE3_A), which undergo additional stress testing per the AEC-Q101 standard. For automotive applications requiring qualification, specify the HE3 suffix and confirm packaging code "H" or "I" per Vishay's ordering table.
How does the bidirectional design of SMAJ78CA-E3/61 affect PCB layout?
The bidirectional nature of SMAJ78CA-E3/61 eliminates polarity constraints during placement - no cathode band marking exists, and either terminal functions identically. This simplifies automated pick-and-place programming, avoids orientation-related assembly errors, and allows use on AC-coupled lines or floating grounds where voltage polarity reverses, such as in RS-485 or isolated DC-DC feedback paths.
What is the thermal resistance of SMAJ78CA-E3/61, and how does it impact power derating?
SMAJ78CA-E3/61 has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on minimum recommended 0.2" × 0.2" copper pads. This value directly governs power derating above 25 °C ambient: per Figure 2 in the datasheet, power dissipation must be reduced linearly to zero at +150 °C junction temperature - meaning at 100 °C ambient, usable PD drops to ~1.4 W from the rated 3.3 W.
Can SMAJ78CA-E3/61 replace SMAJ78A-E3/61 in an existing design?
SMAJ78CA-E3/61 can replace SMAJ78A-E3/61 only if the circuit does not rely on unidirectional conduction or forward voltage drop (VF = 3.5 V @ 25 A). Since SMAJ78CA-E3/61 lacks polarity marking and exhibits symmetrical behavior, it introduces no reverse leakage penalty but cannot provide crowbar action. Layout changes are unnecessary, but functional validation under surge and steady-state bias is required.
SMAJ78CA-E3/61 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ78CA-E3/61 FAQ
1.How can I place an order for SMAJ78CA-E3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78CA-E3/61 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 SMAJ78CA-E3/61 reliable?
The price and inventory of SMAJ78CA-E3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78CA-E3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ78CA-E3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78CA-E3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78CA-E3/61?
SMAJ78CA-E3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78CA-E3/61 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 SMAJ78CA-E3/61?
For technical support, including SMAJ78CA-E3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78CA-E3/61 requirements.
6.How does Aetrix verify that SMAJ78CA-E3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ78CA-E3/61 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 SMAJ78CA-E3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ78CA-E3/61?
All SMAJ78CA-E3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78CA-E3/61, 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 SMAJ78CA-E3/61 part is unused and in its original packaging.
Return procedure for SMAJ78CA-E3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78CA-E3/61 Tags
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