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Microchip Technology SMAJ78E3/TR13
- Part No.:
- SMAJ78E3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78E3/TR13.pdf
- Description:
- TVS DIODE 78VWM 139VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,834
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Product details
Overview
SMAJ78E3/TR13 from Microsemi is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for 500 W peak pulse power clamping at 10/1000 µs waveform, with 78 V working standoff voltage (VWM), 86.7 V minimum breakdown voltage (VBR), and 139 V maximum clamping voltage (VC) at 3.6 A peak pulse current - deployed in industrial power supplies to protect MOSFET gate drivers from inductive switching transients.
For engineers reviewing the SMAJ78E3/TR13 datasheet, SMAJ78E3/TR13 pinout, SMAJ78E3/TR13 application, or SMAJ78E3/TR13 equivalent, key selection criteria include verified 78 V standoff rating, RoHS-compliant matte-tin plating, DO-214AC package compatibility, and IEC61000-4-5 secondary lightning protection compliance up to Class 4 (12 Ω source impedance).
Technical Context
This TVS operates as a unidirectional avalanche diode with cathode-band polarity marking, optimized for fast clamping response (<100 ps theoretical rise time) and low thermal resistance (15 °C/W junction-to-lead). It delivers precise overvoltage protection by entering avalanche conduction when reverse voltage exceeds VBR, limiting transient energy via controlled clamping at VC.
Its electrical behavior is defined under standardized 10/1000 µs double-exponential surge testing per IEC61000-4-5, with guaranteed 1 µA maximum standby leakage at 78 V and 1 mA breakdown test current. The device sustains 40 A forward surge (8.3 ms half-sine) only in unidirectional configuration - not applicable to bidirectional variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before clamping initiates; sets system-level DC bus protection threshold. |
| VBR min | 86.7 V @ 1 mA - guaranteed avalanche onset voltage; ensures predictable turn-on margin above VWM. |
| VC @ IPP | 139 V @ 3.6 A - clamped voltage during 10/1000 µs surge; defines worst-case stress on downstream ICs. |
| PPP | 500 W - peak pulse power handling capability; enables robust protection against high-energy transients. |
| ID max | 1 µA @ VWM - ultra-low leakage current; prevents measurable power loss or false triggering in high-impedance circuits. |
| TJ range | –65 °C to +150 °C - extended operating temperature envelope supports automotive under-hood and industrial motor drive environments. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, void-free thermosetting epoxy body meeting UL94V-0; terminals feature C-bend (modified J-bend) leads with RoHS-compliant annealed matte-tin plating solderable per MIL-STD-750 Method 2026; cathode indicated by band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to circuit ground or lowest potential node; completes current path during clamping. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., DC bus); avalanche conduction occurs when voltage exceeds VBR relative to anode. |
Key Features
| Feature | Design Value |
|---|---|
| RoHS-compliant "e3" suffix | Matte-tin plating meets EU Directive 2011/65/EU; eliminates lead-based solder compatibility concerns. |
| DO-214AC mechanical outline | Standardized footprint compatible with automated SMT placement and reflow; matches JEDEC MS-013AA dimensions (A=1.70–2.26 mm, D=4.93–5.48 mm). |
| IEC61000-4-5 Class 4 support | Validated for secondary lightning protection with 12 Ω source impedance - covers highest severity level for AC mains-connected equipment. |
| Moisture sensitivity Level 1 | No dry-pack required per IPC/JEDEC J-STD-020B; simplifies handling and eliminates bake-out prior to assembly. |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of IGBT gate driver inputs against voltage spikes induced by transformer leakage inductance during PWM switching. IC Role / Device Role / Timing Role: Unidirectional TVS placed between gate and source pins to clamp negative-going transients below –5 V absolute rating. Use Value: Prevents gate oxide damage by limiting transient voltage to ≤139 V while maintaining <1 µA leakage at 78 V DC bias. | Use Scenario: Input-stage surge suppression on 48 V DC telecom rectifier outputs feeding backplane distribution networks. IC Role / Device Role / Timing Role: Primary clamping element across DC output rails to absorb 500 W surges from load-dump or hot-swap events. Use Value: Enables compliance with GR-1089-CORE Section 4.5.2 for telecom central office equipment without derating or parallel devices. |
| Automotive Body Control Modules | Industrial PLC I/O Modules |
Use Scenario: Protection of LIN bus transceivers connected to battery-supplied 12 V lines subject to load dump and jump-start transients. IC Role / Device Role / Timing Role: Standoff-rated TVS placed at transceiver VCC pin to limit supply rail overshoot during ISO 7637-2 Pulse 5a events. Use Value: Maintains 78 V VWM margin above nominal 12 V system while clamping to 139 V - sufficient headroom for 120 V peak pulses. | Use Scenario: Analog input channel protection in programmable logic controllers exposed to field-wiring ESD and inductive kickback from solenoid valves. IC Role / Device Role / Timing Role: Front-end TVS on 24 V sensor supply line to shunt transients before they reach precision ADC front-end op-amps. Use Value: Delivers 500 W clamping capacity with <100 ps response - faster than typical op-amp slew rate, ensuring upstream protection. |
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-E3/5A (Vishay) | Identical VWM (78 V), VBR min (86.7 V), and VC (139 V), but rated for 100% screening per MIL-PRF-19500 JANTX with optional MX prefix. | Supports avionics-grade qualification paths unavailable with SMAJ78E3/TR13; same DO-214AC footprint and RoHS compliance. | Select SMAJ78A-E3/5A if MIL-spec screening or extended reliability validation is required; otherwise SMAJ78E3/TR13 suffices for commercial/industrial use. |
| SMCJ78A (Littelfuse) | Higher PPP (1500 W), larger DO-214AB package (7.11 × 6.22 mm vs. 4.57 × 2.79 mm), and higher VC (150 V @ 10.7 A). | Used where higher surge energy must be absorbed without board area penalty; incompatible with SMAJ78E3/TR13's DO-214AC land pattern. | Choose SMCJ78A only when 1500 W surge rating is mandatory and PCB layout allows larger footprint; SMAJ78E3/TR13 remains optimal for space-constrained 500 W designs. |
Compared with SMAJ78A-E3/5A and SMCJ78A, SMAJ78E3/TR13 offers the smallest DO-214AC package with verified 500 W clamping at minimal leakage (1 µA), making it ideal for high-density industrial PCBs where screening beyond commercial grade is unnecessary.
Availability
SMAJ78E3/TR13 is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, and automotive body control modules requiring stable component supply with full traceability and RoHS compliance.
Supply support for SMAJ78E3/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 components for aerospace, defense, and industrial markets.
The SMAJ series was engineered specifically for surface-mount transient suppression in space-constrained, high-surge environments - delivering 500 W clamping in the industry-standard DO-214AC package with validated IEC61000-4-2/4-4/4-5 compliance.
FAQ
What is the clamping voltage of SMAJ78E3/TR13 at its rated peak pulse current?
The SMAJ78E3/TR13 has a maximum clamping voltage (VC) of 139 V when subjected to its specified peak pulse current of 3.6 A under the standard 10/1000 µs waveform. This value is measured per Figure 2 in the official Microsemi datasheet MSC0270A and defines the upper voltage limit imposed on protected circuitry during surge events - critical for ensuring downstream ICs remain within absolute maximum ratings.
Is SMAJ78E3/TR13 unidirectional or bidirectional, and how is polarity marked?
SMAJ78E3/TR13 is a unidirectional TVS diode, indicated by the absence of "C" or "CA" in its part number. Polarity is marked by a cathode band on the device body - the banded end connects to the higher-potential line being protected, while the anode connects to ground or the lower-potential reference. Bidirectional versions (e.g., SMAJ78CA) would require different circuit integration and lack this banding.
Does SMAJ78E3/TR13 meet IEC61000-4-5 for lightning surge immunity?
Yes, SMAJ78E3/TR13 is validated for IEC61000-4-5 secondary lightning surge immunity up to Class 4 with 12 Ω source impedance, covering the highest severity level for equipment connected to AC mains or long cables. Its 500 W peak pulse power rating and 139 V clamping voltage ensure compliance when applied per recommended PCB layout and grounding practices outlined in Microsemi Application Note AN-1001.
What is the maximum steady-state power dissipation of SMAJ78E3/TR13 on a standard FR4 board?
When mounted on a standard FR4 printed circuit board with 1 oz copper and the recommended footprint, SMAJ78E3/TR13 dissipates up to 1.56 W continuously at ambient temperature (TA = 25 °C), or 5 W at lead temperature (TL = 75 °C). These values derive from its thermal resistance of 80 °C/W (junction-to-ambient) and 15 °C/W (junction-to-lead), respectively - essential for thermal design margining in enclosed enclosures.
Can SMAJ78E3/TR13 be used in place of SMAJ78A without layout changes?
Yes, SMAJ78E3/TR13 and SMAJ78A share identical DO-214AC package dimensions, pinout, and electrical specifications (VWM = 78 V, VBR min = 86.7 V, VC = 139 V), making them functionally and mechanically interchangeable. The "E3" suffix denotes RoHS-compliant matte-tin plating, while "A" indicates the same unidirectional configuration - no PCB modifications are needed for substitution in existing designs.
SMAJ78E3/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:
- 1
- Bidirectional Channels:
- -
- 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)
SMAJ78E3/TR13 FAQ
1.How can I place an order for SMAJ78E3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78E3/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 SMAJ78E3/TR13 reliable?
The price and inventory of SMAJ78E3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78E3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ78E3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78E3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78E3/TR13?
SMAJ78E3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78E3/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 SMAJ78E3/TR13?
For technical support, including SMAJ78E3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78E3/TR13 requirements.
6.How does Aetrix verify that SMAJ78E3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ78E3/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 SMAJ78E3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ78E3/TR13?
All SMAJ78E3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78E3/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 SMAJ78E3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ78E3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78E3/TR13 Tags
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