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Diodes Incorporated SMAJ78A-13-F
- Part No.:
- SMAJ78A-13-F
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78A-13-F.pdf
- Description:
- TVS DIODE 78V 126V SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,761
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Product details
Overview
SMAJ78A-13-F from Diodes Incorporated is a unidirectional 400W transient voltage suppressor (TVS) diode in SMA package, designed for primary overvoltage protection on DC power rails and signal lines. It features 78V reverse standoff voltage (VRWM), 86.7–95.8V breakdown range (VBR), 126V max clamping voltage (VC) at 3.2A peak pulse current (IPP), and operates from –55°C to +150°C - used in automotive power supply input stages and industrial sensor interfaces.
For engineers reviewing the SMAJ78A-13-F datasheet, SMAJ78A-13-F pinout, SMAJ78A-13-F application, or SMAJ78A-13-F equivalent, key selection criteria include clamping voltage margin vs. protected IC VCC rating, peak pulse current capability under IEC 61000-4-5 surge conditions, thermal derating above +25°C ambient, and compatibility with automated SMT assembly using RoHS-compliant reflow profiles.
Technical Context
This TVS diode employs glass-passivated silicon junction construction for stable clamping performance and fast response (<1 ns) to ESD and surge transients. Its unidirectional configuration provides low forward voltage drop (VF = 3.5 V @ 35 A) while maintaining high surge robustness (40 A IFSM, 8.3 ms half-sine).
Thermal design relies on PCB copper area for heat dissipation, with steady-state power derating starting at +75°C lead temperature (PM(AV) = 1.0 W). The device meets JEDEC moisture sensitivity level 1 and supports lead-free reflow per MIL-STD-202, Method 208.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power | 400 W - sustains single 8.3/20 µs surges without failure under defined test conditions |
| Reverse Standoff Voltage | 78 V - maximum continuous DC or RMS voltage before significant leakage begins |
| Clamping Voltage | 126 V @ 3.2 A IPP - limits transient voltage seen by downstream circuitry during surge events |
| Breakdown Voltage | 86.7–95.8 V @ 1.0 mA IT - defines minimum voltage at which avalanche conduction initiates reliably |
| Operating Temperature | –55°C to +150°C - enables use in under-hood automotive and industrial environments |
| Package | SMA - surface-mount outline with 2.29–2.92 mm height and 4.00–4.60 mm width, compatible with standard pick-and-place |
Pinout & Package
Two-terminal SMA package: anode and cathode terminals identified by cathode band marking on unidirectional devices. Standard SMA footprint requires 2.50 mm pad width (X), 6.50 mm pad length (X1), and 1.70 mm spacing (Y) per Diodes' recommended layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point in forward bias | Connected to ground or lower-potential rail in unidirectional TVS configuration |
| Cathode | Current exit point in forward bias; high-impedance terminal in reverse standby | Connected to protected line (e.g., 24 V supply); clamps to anode when voltage exceeds VRWM |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse power | Enables compliance with IEC 61000-4-5 Level 4 (4 kV/2 Ω) surge testing on 24 V systems |
| Glass passivated die | Ensures long-term stability of breakdown voltage and leakage current across temperature and humidity stress |
| RoHS-compliant matte tin plating | Supports Pb-free reflow soldering at peak temperatures up to 260°C without degradation |
| UL 94V-0 molded plastic case | Provides flame-retardant housing required for automotive and industrial safety certifications |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
Use Scenario: Protects microcontroller GPIO and CAN transceiver power pins from load dump and jump-start surges in 12 V/24 V vehicle electrical systems. IC Role / Device Role: Primary clamping element placed between fused battery feed and local LDO regulator input. Use Value: Limits transient voltage to ≤126 V, preserving integrity of 36 V-rated input capacitors and preventing latch-up in downstream logic. | Use Scenario: Shields 24 V digital input optocoupler front-end from field-wiring induced surges and inductive kickback. IC Role / Device Role: First-stage overvoltage clamp ahead of series current-limiting resistor and Zener shunt regulator. Use Value: Absorbs 400 W pulses without degradation, enabling >100,000 surge cycles per IEC 61000-4-4 specification. |
| Telecom Remote Radio Unit (RRU) | Medical Infusion Pump Power Supply |
Use Scenario: Guards Ethernet PHY power pins against lightning-induced surges entering via outdoor cabling in base station equipment. IC Role / Device Role: Secondary protection device after gas discharge tube (GDT), providing low-clamp refinement. Use Value: Fast <1 ns response captures residual energy missed by slower GDT, reducing stress on 100 V-rated DC-DC converter MOSFETs. | Use Scenario: Safeguards 5 V/12 V auxiliary rails feeding motor drivers and display controllers from ESD and switching noise. IC Role / Device Role: Final-stage transient suppressor on isolated secondary side of medical-grade AC-DC adapter. Use Value: Meets IEC 60601-1 creepage/clearance requirements via compact SMA footprint and UL 94V-0 housing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A-E3/5A (Vishay) | Identical VRWM (78 V), VC = 126 V @ 3.2 A, but rated for 150°C TJ max (vs. 150°C for Diodes) | Qualified to AEC-Q101 Grade 0; suitable for under-hood automotive where extended temperature validation is mandated | Select if AEC-Q101 qualification documentation and PPAP support are contractually required |
| P6SMB78A (ON Semiconductor) | Same SMA package and 78 V VRWM, but higher VC = 130 V @ 3.1 A and lower PPK = 600 W (derated to 400 W at 100°C) | Higher clamping voltage reduces margin for 100 V-rated components; better suited for less sensitive 24 V systems with wider tolerance | Choose when cost sensitivity outweighs clamping precision and full 400 W rating at elevated ambient is not needed |
Compared with SMAJ78A-E3/5A and P6SMB78A, SMAJ78A-13-F offers tighter clamping (126 V), verified RoHS 3 compliance, and optimized thermal resistance for high-volume SMT production - making it preferred for industrial control and telecom infrastructure where consistency and process compatibility are critical.
Availability
SMAJ78A-13-F is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, telecom remote radio units, and medical infusion pump power supplies requiring stable component supply and traceable sourcing.
Supply support for SMAJ78A-13-F 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
This part belongs to Diodes' SMAJ series of surface-mount TVS diodes, engineered specifically for high-reliability transient suppression in automotive, industrial, and communications systems where compact size and repeatable clamping performance are essential.
FAQ
What is the maximum clamping voltage of SMAJ78A-13-F and under what test condition is it specified?
The maximum clamping voltage is 126 V, measured at a peak pulse current (IPP) of 3.2 A using the 8.3 ms/20 µs double-exponential waveform per IEC 61000-4-5. This value is guaranteed across the full operating temperature range (–55°C to +150°C) and represents the upper limit of voltage imposed on protected circuitry during surge events.
Does SMAJ78A-13-F have AEC-Q101 qualification for automotive use?
No - SMAJ78A-13-F is a standard-grade part qualified per JESD22 reliability standards but not AEC-Q101. For automotive applications requiring AEC-Q101 certification, Diodes offers the pin-compatible SMAJ78AQ-13-F variant, which undergoes additional stress testing and is manufactured in IATF 16949-certified facilities.
How does the SMA package affect thermal performance in continuous operation?
In steady-state conditions, the SMA package limits power dissipation to 1.0 W at TL = +75°C, with linear derating to zero at +150°C. Effective thermal management requires ≥1 cm² of 1 oz copper connected to both terminals on the PCB; insufficient copper area causes rapid junction temperature rise and premature failure under sustained surge duty cycles.
Can SMAJ78A-13-F be used in bidirectional signal line protection?
No - SMAJ78A-13-F is unidirectional only, indicated by the absence of "C" suffix. For bidirectional protection (e.g., RS-485, USB D+/D–), use SMAJ78CA-13-F, which has symmetric clamping in both polarities and no cathode band marking. Substituting the unidirectional version on AC-coupled lines risks forward conduction and permanent damage.
SMAJ78A-13-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
SMAJ78A-13-F FAQ
1.How can I place an order for SMAJ78A-13-F through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78A-13-F 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 SMAJ78A-13-F reliable?
The price and inventory of SMAJ78A-13-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78A-13-F is usually 5 days.
3.What payment methods are accepted for SMAJ78A-13-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78A-13-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78A-13-F?
SMAJ78A-13-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78A-13-F 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 SMAJ78A-13-F?
For technical support, including SMAJ78A-13-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78A-13-F requirements.
6.How does Aetrix verify that SMAJ78A-13-F is sourced from the original manufacturer or authorized distributors?
All SMAJ78A-13-F 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 SMAJ78A-13-F meets industry standards.
7.What is the process for return or replacement of SMAJ78A-13-F?
All SMAJ78A-13-F units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78A-13-F, 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 SMAJ78A-13-F part is unused and in its original packaging.
Return procedure for SMAJ78A-13-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78A-13-F Tags
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ESD9B5.0ST5G
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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