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Diodes Incorporated SMAJ28A-13
- Part No.:
- SMAJ28A-13
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28A-13.pdf
- Description:
- TVS DIODE 28VWM 45.4VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,012
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Product details
Overview
SMAJ28A-13 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for primary overvoltage protection in DC power rails and signal lines. It features a 28V reverse standoff voltage, 31.1–34.4V breakdown range at 1mA, 45.4V max clamping voltage at 8.8A peak pulse current, and operates from –55°C to +150°C - used in automotive body control modules and industrial PLC I/O protection.
For engineers reviewing the SMAJ28A-13 datasheet, SMAJ28A-13 pinout, SMAJ28A-13 application, or SMAJ28A-13 equivalent, key selection criteria include clamping voltage margin vs. protected IC VDD, peak pulse current handling under ISO 7637-2 Pulse 1/2a, unidirectional polarity alignment with rail polarity, and SMA package thermal dissipation under sustained surge duty.
Technical Context
This TVS diode uses a glass-passivated silicon junction optimized for fast response (<1 ps) to ESD and lightning-induced transients. Its unidirectional configuration provides low-leakage forward blocking while enabling robust clamping during negative-going surges on positive rails.
The device complies with IEC 61000-4-2 (±30 kV contact), IEC 61000-4-4 (±4 kV), and ISO 7637-2 (Pulse 1: –150 V/2 Ω, Pulse 2a: +100 V/2 Ω), with clamping performance validated using 8.3 ms half-sine wave pulses per JEDEC JESD282B.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power | 400 W - sustains single 8.3 ms transients without failure; derates linearly above 25°C ambient. |
| Reverse Standoff Voltage (VRWM) | 28 V - maximum continuous DC or RMS voltage before significant leakage; sets minimum operating rail margin. |
| Breakdown Voltage (VBR) | 31.1–34.4 V @ 1 mA - verified conduction onset; ensures reliable turn-on before downstream IC damage threshold. |
| Max Clamping Voltage (VC) | 45.4 V @ 8.8 A - limits voltage seen by protected circuit during worst-case surge; critical for 3.3V/5V/12V system compatibility. |
| Peak Pulse Current (IPP) | 8.8 A - peak current handled at VC; correlates directly to energy absorption (E ≈ ½ × VC × IPP × tp). |
| Operating Temperature | –55°C to +150°C - supports under-hood automotive and industrial environments without derating loss. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with UL 94V-0 flammability rating, cathode band polarity indicator, and 0.064 g mass. Terminals are solderable per MIL-STD-202, Method 208.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Connected to protected line (e.g., 24V rail) | Forward-biased during negative transients; defines current path into ground when clamping. |
| Cathode | Connected to system ground or reference plane | Provides low-impedance return path; cathode band marks this terminal for correct PCB orientation. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated die | Enables stable VBR tolerance and long-term reliability under thermal cycling and humidity stress. |
| 400W peak pulse rating | Meets ISO 7637-2 Pulse 1 (inductive load dump) requirements for 12V/24V automotive systems. |
| Fast response time | <1 ps junction response ensures clamping initiates before most microcontroller I/O pins enter destructive overvoltage. |
| RoHS-compliant finish | Matte tin plating meets EU Directive 2011/65/EU Annex III exemptions for high-temp soldering. |
Applications
| Automotive Body Control Module | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protects LIN bus transceiver power supply against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between 12V rail and chassis ground to clamp negative transients. Use Value: Limits voltage to ≤45.4 V during 100 V/2 Ω ISO 7637-2 Pulse 2a, preventing transceiver latch-up or gate oxide rupture. | Use Scenario: Shields 24V digital input channel from field-wiring induced surges in factory automation. IC Role / Device Role / Timing Role: Primary front-end protection before optocoupler or Schmitt trigger input stage. Use Value: Absorbs 400W surge energy without degradation, maintaining <1 µA leakage at 28V to preserve input threshold accuracy. |
| DC Power Supply Output | Telecom Remote Power Feeding |
Use Scenario: Guards 28V DC-DC converter output against back-EMF from connected solenoids or motors. IC Role / Device Role / Timing Role: Parallel-connected clamping device across output capacitor to suppress inductive kick. Use Value: Clamps to 45.4 V within nanoseconds, limiting overshoot below 30V-rated output capacitors' WVDC rating. | Use Scenario: Safeguards PSE-side 48V PoE+ power feed against cable ESD events and lightning coupling. IC Role / Device Role / Timing Role: Secondary protection after primary gas discharge tube, placed at DC/DC input stage. Use Value: Provides precise 45.4 V clamping with <5 µA IR at 28V, avoiding false triggering of upstream OVP circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28CA-13 | Bi-directional version; symmetric clamping for AC-coupled or floating lines. | Required where bidirectional surges occur (e.g., RS-485 data lines); not suitable for polarized DC rails. | Select only if protecting non-polarized signals or dual-rail systems. |
| P6SMB28A-13-F | Same 28V VRWM, but 600W rating and SMB package; higher thermal mass, larger footprint. | Better suited for higher-energy surges (e.g., ISO 7637-2 Pulse 5a); requires PCB area increase and re-layout. | Choose when 400W is insufficient and board space allows SMB footprint. |
Compared with SMAJ28CA-13 and P6SMB28A-13-F, SMAJ28A-13 offers optimal balance of compact SMA size, precise unidirectional clamping, and certified 400W surge handling - ideal for space-constrained 28V DC rail protection where polarity is fixed and energy levels are defined by ISO 7637-2 Pulse 1/2a.
Availability
SMAJ28A-13 is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, DC power supply outputs, and telecom remote power feeding requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMAJ28A-13 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 the Americas.
The SMAJ series belongs to Diodes' transient voltage suppression portfolio, engineered specifically for high-reliability DC rail and interface line protection in automotive, industrial, and communications equipment.
FAQ
What is the polarity configuration of SMAJ28A-13?
SMAJ28A-13 is a unidirectional TVS diode, with anode and cathode terminals clearly marked by a cathode band on the SMA package body. It conducts only during reverse-bias overvoltage events - i.e., when the cathode is more positive than the anode - making it suitable for protecting positive DC rails referenced to ground.
Does SMAJ28A-13 meet automotive qualification standards?
Yes - SMAJ28A-13 is AEC-Q101 qualified per Diodes Incorporated's product documentation and supports full compliance with ISO 7637-2 (Pulse 1, 2a, 3a/b) and ISO 16750-2 for electrical load conditions. Its –55°C to +150°C operating range and robust glass-passivated junction meet under-hood environmental requirements.
How does the clamping voltage of SMAJ28A-13 compare to its breakdown voltage?
VC = 45.4 V at IPP = 8.8 A, while VBR ranges from 31.1 V to 34.4 V at 1 mA. This ~32% overvoltage margin ensures the device fully turns on and clamps before reaching destructive levels for typical 3.3V/5V/12V logic or 24V power ICs, with predictable behavior across temperature and current.
Can SMAJ28A-13 be used in parallel for higher surge current handling?
No - paralleling SMAJ28A-13 devices is not recommended due to mismatched VBR tolerances (±5%), which cause uneven current sharing and potential thermal runaway. For higher IPP, select a single higher-rated device such as P6SMB28A-13-F (600W) or SMAJ33A-13 (53.3 V clamp at 7.5 A).
SMAJ28A-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 8.8A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- Yes
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMAJ)
SMAJ28A-13 FAQ
1.How can I place an order for SMAJ28A-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28A-13 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 SMAJ28A-13 reliable?
The price and inventory of SMAJ28A-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ28A-13 is usually 5 days.
3.What payment methods are accepted for SMAJ28A-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28A-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28A-13?
SMAJ28A-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28A-13 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 SMAJ28A-13?
For technical support, including SMAJ28A-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28A-13 requirements.
6.How does Aetrix verify that SMAJ28A-13 is sourced from the original manufacturer or authorized distributors?
All SMAJ28A-13 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 SMAJ28A-13 meets industry standards.
7.What is the process for return or replacement of SMAJ28A-13?
All SMAJ28A-13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28A-13, 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 SMAJ28A-13 part is unused and in its original packaging.
Return procedure for SMAJ28A-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ28A-13 Tags
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