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Microchip Technology SMAJ78CE3/TR13
- Part No.:
- SMAJ78CE3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78CE3/TR13.pdf
- Description:
- TVS DIODE 78VWM 139VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ78CE3/TR13 from Microsemi is a bidirectional surface-mount transient voltage suppressor (TVS) designed for high-energy surge protection in DC power rails and signal lines. It features a 78 V standoff voltage (VWM), 86.7 V minimum breakdown voltage (VBR), 139 V maximum clamping voltage (VC) at 3.6 A peak pulse current, and 500 W peak pulse power rating per 10/1000 µs waveform - deployed in telecom power supplies, industrial I/O modules, and automotive body control units.
For engineers reviewing the SMAJ78CE3/TR13 datasheet, SMAJ78CE3/TR13 pinout, SMAJ78CE3/TR13 application, or SMAJ78CE3/TR13 equivalent, key selection criteria include bidirectional clamping capability, RoHS-compliant matte-tin plating, DO-214AC package compatibility, IEC61000-4-2/4-4/4-5 compliance, and 139 V clamping performance under 3.6 A transient stress.
Technical Context
The SMAJ78CE3/TR13 operates as a symmetrical avalanche diode pair in anti-parallel configuration, enabling equal clamping in both polarities without external biasing. Its <100 ps theoretical response time ensures effective suppression of ESD events per IEC61000-4-2 Level 4 (±15 kV contact), while its 139 V clamping voltage limits downstream voltage stress during 42 Ω source impedance lightning surges per IEC61000-4-5 Class 1.
Thermal design relies on low junction-to-lead thermal resistance (15 °C/W) and FR4 board mounting with recommended footprint; steady-state dissipation is rated at 1.56 W at 25 °C ambient and 5 W at 75 °C lead temperature. The device exhibits ≤3.6 µA standby leakage at 78 V and supports 100% temperature cycling screening when ordered with MA prefix.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Standoff) | 78 V - Maximum continuous reverse voltage before conduction begins; sets operating margin for 72–80 V DC rails. |
| VBR (Min) | 86.7 V @ 1 mA - Confirmed avalanche onset threshold; ensures reliable triggering above normal operating voltage. |
| VC @ IPP | 139 V @ 3.6 A - Clamped voltage during 10/1000 µs surge; defines worst-case overvoltage seen by protected ICs. |
| PPP | 500 W - Peak pulse power handling per standard waveform; enables robust protection against induced transients and switching spikes. |
| ID @ VWM | ≤3.6 µA - Ultra-low leakage at rated standoff; prevents measurable power loss or false triggering in high-impedance circuits. |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline with wide leads for thermal and mechanical reliability on PCBs. |
| RoHS | e3 suffix - Matte-tin plating compliant with EU RoHS Directive 2011/65/EU; no lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE. |
Pinout & Package
DO-214AC (SMA) package: molded thermosetting epoxy case meeting UL94V-0, C-bend (modified J-bend) leads, void-free construction, 0.064 g weight, moisture sensitivity level 1 (no dry pack required).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (Bidirectional) | Reversible polarity terminals | No cathode band marking; symmetric conduction in both directions - simplifies layout and eliminates orientation errors in AC or floating rail protection. |
| Case / Body | Non-electrical mechanical interface | Thermally conductive epoxy body transfers heat to PCB copper; requires recommended pad layout (A=1.70–2.26 mm, D=4.93–5.48 mm) for optimal thermal derating. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity constraints - reduces BOM count vs. dual unidirectional TVS. |
| IEC61000-4-5 Class 1 compliance | Validated for secondary lightning surges with 42 Ω source impedance up to 78 V standoff - meets industrial fieldbus and building automation immunity requirements. |
| Fast response (<100 ps theoretical) | Prevents voltage overshoot during nanosecond-scale ESD events - critical for safeguarding high-speed logic and analog front-ends. |
| RoHS-compliant matte-tin plating | Ensures solderability per MIL-STD-750 Method 2026 and long-term intermetallic stability - eliminates lead-based assembly concerns. |
| 500 W peak pulse power | Supports high-energy transients in 24/48 V industrial power systems - exceeds typical PPP requirements for PLC I/O and motor drive control boards. |
Applications
| Industrial PLC Analog Input Modules | Automotive Body Control Units (BCUs) |
|---|---|
Use Scenario: Protection of 0–10 V or 4–20 mA sensor inputs against load dump, inductive kickback, and ESD during field wiring. IC Role / Device Role / Timing Role: Bidirectional TVS placed at connector entry point to clamp both positive and negative transients before reaching precision ADC and op-amp front-end. Use Value: 139 V clamping ensures downstream components see no more than 139 V during 3.6 A surge - preserving 16-bit ADC accuracy and preventing latch-up in rail-to-rail input stages. | Use Scenario: Safeguarding LIN bus transceivers and microcontroller GPIOs from battery reverse connection, jump-start spikes, and alternator load dump. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12 V supply rail and LIN data line, operating in parallel with local decoupling capacitors. Use Value: 78 V standoff allows safe operation across full automotive battery range (9–16 V), while 500 W rating handles 100 ms load dump pulses without degradation. |
| Telecom Power Supply Outputs | Building Automation HVAC Controllers |
Use Scenario: Output rail protection for 48 V DC-DC converters feeding PoE injectors and remote radio units. IC Role / Device Role / Timing Role: Final-stage transient suppressor after bulk filtering and before point-of-load regulators - absorbs residual switching noise and lightning-induced surges. Use Value: 86.7 V breakdown guarantees activation only during fault conditions, avoiding interference with normal 48 V ±10% regulation window. | Use Scenario: Protection of RS-485 transceivers and thermostat interfaces exposed to long cable runs in commercial HVAC ducts. IC Role / Device Role / Timing Role: Line-side TVS on differential bus pairs, mounted adjacent to connector to minimize inductance and maximize clamping effectiveness. Use Value: Symmetrical 139 V clamping maintains common-mode rejection integrity during EFT bursts per IEC61000-4-4, preventing data corruption on multi-drop networks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78AHE3/TR13 | Unidirectional version with cathode band marking; same VWM, VBR, VC, and PPP. | Requires explicit polarity assignment; unsuitable for AC or floating signals but offers lower leakage in DC-only paths. | Select SMAJ78AHE3/TR13 only when protecting unidirectional DC rails where polarity is fixed and leakage below 1 µA is critical. |
| SMBJ78CE3/TR13 | Same electrical specs but in larger DO-214AA (SMB) package; 600 W PPP rating due to improved thermal mass. | Higher surge margin and better thermal endurance; occupies more PCB area and has higher inductance. | Choose SMBJ78CE3/TR13 for designs requiring extended surge life or operating near thermal limits - not a drop-in replacement due to footprint mismatch. |
Compared with SMAJ78CE3/TR13, SMAJ78AHE3/TR13 trades bidirectional flexibility for tighter unidirectional leakage control, while SMBJ78CE3/TR13 provides higher thermal capacity at the cost of board space and layout redesign - making SMAJ78CE3/TR13 the optimal balance of size, symmetry, and 500 W protection for space-constrained industrial and automotive PCBs.
Availability
SMAJ78CE3/TR13 is available at Aetrix Electronics and suitable for industrial PLC analog input modules, automotive body control units, and telecom power supply outputs requiring stable component supply, RoHS compliance, and IEC61000-4-2/4-4/4-5 certified surge protection.
Supply support for SMAJ78CE3/TR13 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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal solutions for aerospace, defense, industrial, and communications markets.
The SMAJ series was engineered for surface-mount transient suppression in harsh environments - delivering consistent 500 W surge capability, fast response, and rugged packaging for mission-critical power and signal line protection.
FAQ
What does the 'C' suffix in SMAJ78CE3/TR13 indicate?
The 'C' suffix in SMAJ78CE3/TR13 denotes a bidirectional configuration - meaning the device functions identically in both polarities without a designated anode or cathode. This eliminates orientation concerns during placement and enables protection of AC-coupled or floating circuits. Unlike unidirectional variants (e.g., SMAJ78AE3/TR13), SMAJ78CE3/TR13 has no cathode band marking and exhibits symmetrical VBR and VC characteristics.
Is SMAJ78CE3/TR13 compliant with IEC61000-4-5 for lightning surge protection?
Yes, SMAJ78CE3/TR13 is validated for secondary lightning surge protection per IEC61000-4-5 with 42 Ω source impedance up to Class 1 (78 V standoff). Its 139 V clamping voltage at 3.6 A ensures protected circuits remain within safe operating limits during standardized 1.2/50 µs open-circuit voltage and 8/20 µs short-circuit current waveforms. This makes SMAJ78CE3/TR13 suitable for industrial Ethernet ports, building automation controllers, and telecom power interfaces.
What is the thermal resistance specification for SMAJ78CE3/TR13?
SMAJ78CE3/TR13 has a junction-to-lead thermal resistance (RθJL) of 15 °C/W and a junction-to-ambient resistance (RθJA) of 80 °C/W when mounted on a standard FR4 PCB with 1 oz copper and the manufacturer-recommended pad layout. These values define derating curves for continuous power dissipation: 1.56 W at 25 °C ambient and 5 W at 75 °C lead temperature. Proper thermal pad design is essential to maintain reliability under repeated surge events.
Does SMAJ78CE3/TR13 require dry packing per J-STD-020?
No, SMAJ78CE3/TR13 has a moisture sensitivity level (MSL) of 1 per IPC/JEDEC J-STD-020B, meaning it is not moisture-sensitive and does not require dry packing or baking prior to reflow soldering. The device can be stored indefinitely at ambient conditions and processed using standard lead-free reflow profiles up to 260 °C for 10 seconds - simplifying manufacturing logistics and reducing handling overhead compared to MSL 2+ components.
How does the 'e3' suffix affect the plating and solderability of SMAJ78CE3/TR13?
The 'e3' suffix on SMAJ78CE3/TR13 indicates RoHS-compliant annealed matte-tin plating on the leads, replacing traditional tin-lead finishes. This plating meets MIL-STD-750 Method 2026 for solderability and ensures reliable wetting during both SnPb and lead-free reflow processes. Unlike bright tin, matte-tin resists whisker formation and provides stable intermetallic growth - critical for long-life industrial and automotive applications where SMAJ78CE3/TR13 operates continuously for years.
SMAJ78CE3/TR13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- 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:
- 139V
- Current - Peak Pulse (10/1000µs):
- 3.6A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ78CE3/TR13 FAQ
1.How can I place an order for SMAJ78CE3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78CE3/TR13 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 SMAJ78CE3/TR13 reliable?
The price and inventory of SMAJ78CE3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78CE3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ78CE3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78CE3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78CE3/TR13?
SMAJ78CE3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78CE3/TR13 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 SMAJ78CE3/TR13?
For technical support, including SMAJ78CE3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78CE3/TR13 requirements.
6.How does Aetrix verify that SMAJ78CE3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ78CE3/TR13 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 SMAJ78CE3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ78CE3/TR13?
All SMAJ78CE3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78CE3/TR13, 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 SMAJ78CE3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ78CE3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78CE3/TR13 Tags
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Diodes Incorporated
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Diodes Incorporated
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