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Taiwan Semiconductor Corporation SMDJ12A
- Part No.:
- SMDJ12A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ12A.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:9,132
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Product details
Overview
SMDJ12A from Taiwan Semiconductor is a unidirectional 3000W surface-mount transient voltage suppressor (TVS) diode with a 12V working stand-off voltage, 13.3–14.7V breakdown range at 1mA, and 19.9V maximum clamping voltage at 150.8A peak pulse current. It is designed for robust ESD and surge protection in DC power rails and signal lines of industrial control systems.
For engineers reviewing the SMDJ12A datasheet, SMDJ12A pinout, SMDJ12A application, or SMDJ12A equivalent, key selection criteria include clamping performance under 10/1000μs transients, DO-214AB thermal resistance (RθJA = 75°C/W), unidirectional polarity marking, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b.
Technical Context
The SMDJ12A operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR (13.3–14.7V), clamping transients to ≤19.9V at 150.8A. Its glass-passivated junction ensures stable breakdown and low leakage (<1μA at 12V).
It delivers 3000W peak pulse power (1ms, 10/1000μs waveform), supports 300A non-repetitive forward surge (8.3ms half-sine), and maintains operation across –55°C to +175°C junction temperature with RθJL = 15°C/W for efficient PCB heat transfer.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT=1mA | 13.3–14.7 V - Confirmed breakdown threshold ensuring reliable turn-on margin above VWM |
| VC @ IPPM=150.8A | 19.9 V - Clamped voltage during worst-case 3000W transient, limiting downstream stress |
| PPK | 3000 W - Peak pulse power rating per 10/1000μs waveform, defining surge handling capacity |
| IPPM | 150.8 A - Maximum peak pulse current supported without degradation |
| RθJA | 75 °C/W - Junction-to-ambient thermal resistance in standard JEDEC PCB layout, guiding heatsinking needs |
| Junction Temp Range | –55°C to +175°C - Full operational range enabling use in under-hood or industrial environments |
Pinout & Package
Package: DO-214AB (SMC), surface-mount, unidirectional configuration with cathode band marking. Matte tin-plated leads, J-STD-002 solderable, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path) in unidirectional clamp configuration |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 12V rail); cathode band identifies polarity on package body |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance and long-term reliability under repeated surge stress |
| ISO 7637-2 compliance | Validated for automotive load-dump and switching transient immunity (Pulse 1/2a/2b/3a/3b) |
| Fast response time | <1.0 ps - Enables suppression before sensitive ICs experience overvoltage damage |
| UL 94V-0 molding compound | Meets flammability safety requirement for enclosed industrial and telecom equipment |
| RoHS & halogen-free | Complies with IEC 61249-2-21 and environmental directives for global market deployment |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module |
|---|---|
Use Scenario: Protecting 24V digital input channels in programmable logic controllers from inductive kickback and ESD. IC Role / Device Role / Timing Role: Unidirectional TVS placed between field input and optocoupler input, clamping transients before signal conditioning. Use Value: Limits voltage to ≤19.9V during 150A surges, preserving optocoupler CTR and preventing false triggering. | Use Scenario: Safeguarding LIN bus transceivers and microcontroller GPIOs against battery dump and load-switching noise. IC Role / Device Role / Timing Role: Standoff-rated TVS on 12V supply rail and LIN data line, referenced to chassis ground. Use Value: Meets ISO 7637-2 Pulse 2b (load dump) with 3000W capability, maintaining bus integrity during ignition cycling. |
| Telecom Power Supply Input | Consumer Appliance Motor Drive |
Use Scenario: Front-end protection of AC/DC adapter secondary-side 12V output against lightning-induced surges. IC Role / Device Role / Timing Role: Primary clamping device on DC output rail, coordinated with upstream MOV and fuse. Use Value: Clamps 10/1000μs transients to 19.9V while sustaining 3000W, reducing need for oversized downstream capacitors. | Use Scenario: Suppressing back-EMF spikes from brushed DC motors in smart home appliances. IC Role / Device Role / Timing Role: Mounted across motor terminals, absorbing inductive energy during PWM commutation. Use Value: Handles 300A 8.3ms surge (IFSM), preventing MOSFET drain-source avalanche failure in H-bridge drivers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC12 | Lower peak power (1500W), higher VC (23.2V @ 65A), same DO-214AB package | Not suitable for ISO 7637-2 Pulse 1 (inductive switch-off) where 3000W is required | Select SMDJ12A when full automotive-grade surge immunity is mandatory |
| 1.5SMC12A | Same VWM/VBR specs but lower PPK (1500W), higher VC (21.2V @ 70.8A) | Limited to consumer-grade surge profiles; lacks ISO 7637-2 validation | Choose SMDJ12A for industrial or automotive designs requiring verified 3000W clamping |
Compared with SAC12 and 1.5SMC12A, the SMDJ12A provides 100% higher peak power rating and 15–20% lower clamping voltage at rated current-critical for protecting modern low-voltage logic interfaces without derating margins.
Availability
SMDJ12A is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, and telecom power supply input stages requiring stable component supply and full ISO 7637-2 compliance.
Supply support for SMDJ12A 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial, automotive, and consumer markets since 1979.
The SMDJ series is part of TSC's high-power TVS portfolio, engineered specifically for robust transient immunity in harsh electromagnetic environments-including automotive load-dump, industrial inductive switching, and telecom lightning surge scenarios.
FAQ
What is the maximum clamping voltage of the SMDJ12A under peak pulse conditions?
The SMDJ12A has a maximum clamping voltage (VC) of 19.9 V when subjected to its rated peak pulse current of 150.8 A (10/1000 μs waveform). This value is measured per standard test conditions in the datasheet and defines the upper voltage limit imposed on protected circuits during transient events. The SMDJ12A maintains this clamping performance across its specified junction temperature range.
Is the SMDJ12A suitable for bidirectional transient protection?
No - the SMDJ12A is a unidirectional TVS diode intended for DC rail protection with defined anode/cathode polarity. For bidirectional applications, the SMDJ12CA variant must be used. The SMDJ12A's cathode band marking and electrical characteristics (e.g., forward voltage of 3.5 V at 100 A) confirm its unidirectional design; using it in AC or bipolar signal paths will result in improper clamping behavior.
What is the thermal resistance from junction to ambient for the SMDJ12A?
The SMDJ12A has a junction-to-ambient thermal resistance (RθJA) of 75 °C/W under standard JEDEC test conditions (single-layer 1 in² copper pad). This value assumes no additional heatsinking and guides PCB layout decisions - for sustained power dissipation or elevated ambient temperatures, thermal relief pads or internal copper planes should be added to reduce effective RθJA. The SMDJ12A also specifies RθJL = 15 °C/W for lead-to-junction conduction.
Does the SMDJ12A meet automotive EMC standards?
Yes - the SMDJ12A is explicitly validated to meet ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive switch-off), Pulse 2a/2b (battery disconnection and load dump), and Pulses 3a/3b (capacitive coupling and ignition noise). This certification is documented in Taiwan Semiconductor's official datasheet Version I2104 and confirms suitability for body control modules, infotainment power supplies, and other 12V vehicle subsystems.
What packaging and reel quantity is available for the SMDJ12A?
The SMDJ12A is supplied in DO-214AB (SMC) package on tape-and-reel format, with 3,000 units per reel. The device features matte tin-plated leads compliant with J-STD-002 for solderability, and moisture sensitivity level 1 (MSL-1), meaning it can be stored indefinitely at ≤30°C/60% RH without baking prior to reflow. This packaging supports high-volume automated placement in industrial and automotive manufacturing lines.
SMDJ12A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AB, SMC
- Series:
- SMDJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 150.8A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AB (SMC)
SMDJ12A FAQ
1.How can I place an order for SMDJ12A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ12A 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 SMDJ12A reliable?
The price and inventory of SMDJ12A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ12A is usually 5 days.
3.What payment methods are accepted for SMDJ12A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ12A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ12A?
SMDJ12A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ12A 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 SMDJ12A?
For technical support, including SMDJ12A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ12A requirements.
6.How does Aetrix verify that SMDJ12A is sourced from the original manufacturer or authorized distributors?
All SMDJ12A 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 SMDJ12A meets industry standards.
7.What is the process for return or replacement of SMDJ12A?
All SMDJ12A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ12A, 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 SMDJ12A part is unused and in its original packaging.
Return procedure for SMDJ12A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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