My Inquiry
My Account
Taiwan Semiconductor Corporation SMAJ12C
- Part No.:
- SMAJ12C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12C.pdf
- Description:
- 400W, 14.8V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:6,798
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMAJ12C from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 12V working stand-off voltage (VWM), 13.3–16.3V breakdown voltage (VBR), and 22.0V maximum clamping voltage (VC) at 18.2A peak pulse current. It delivers fast response (<1.0ps), low leakage (<1µA @ VWM), and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive power line protection.
For engineers reviewing the SMAJ12C datasheet, SMAJ12C pinout, SMAJ12C application, or SMAJ12C equivalent, this device is selected for robust overvoltage protection in DC/DC converters, SMPS front-ends, lighting drivers, and automotive body electronics where precise 12V rail clamping and high surge immunity are required.
Technical Context
The SMAJ12C uses a glass-passivated silicon junction optimized for low capacitance and rapid avalanche response. Its unidirectional configuration provides asymmetric clamping-forward conduction limited to 3.5V at 25A, reverse clamping activated above VBR with sub-nanosecond turn-on.
Designed for 10/1000μs waveform compliance, it sustains 400W peak pulse power at TA = 25°C and derates linearly above that temperature per JESD22-A103. Junction temperature range is –55°C to +150°C, supporting under-hood and industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin for 12V systems. |
| VBR min/max | 13.3 V / 16.3 V - Breakdown occurs within this range at 1 mA test current; ensures reliable triggering without premature conduction. |
| VC @ IPPM | 22.0 V - Clamped voltage at 18.2 A peak pulse; guarantees downstream ICs see ≤22V during 10/1000μs transients. |
| PPPM | 400 W - Peak pulse power handling per 10/1000μs waveform; supports high-energy load dump and inductive switching events. |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; minimizes quiescent power loss in battery-powered systems. |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline with 0.060g mass, UL 94V-0 molding, and matte tin-plated leads. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with axial leads, cathode band marking polarity. Cathode terminal is marked by a band on the body; anode is unmarked end. Leads are matte tin-plated and solderable per J-STD-002.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to system ground or return path; completes clamping loop when transient exceeds VBR. |
| Cathode | Protected line input | Connected to 12V rail or signal line; absorbs positive transients by avalanching into ground via anode. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps rise from 0 V to VBR min - enables suppression of nanosecond-scale ESD and fast-switching noise before sensitive circuitry reacts. |
| Glass passivated junction | Stable VBR tolerance and low IR drift over temperature and lifetime - critical for long-term reliability in automotive modules. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) - meets OEM-level automotive EMC requirements. |
| Moisture sensitivity level 1 | No floor life limitation or bake requirement before reflow - simplifies SMT assembly and reduces manufacturing overhead. |
Applications
| Automotive Body Control Module (BCM) | Industrial DC/DC Converter Input Stage |
|---|---|
Use Scenario: Protects microcontroller I/O and CAN transceiver power rails from load dump and jump-start surges in vehicle door modules and lighting controllers. IC Role / Device Role / Timing Role: Unidirectional TVS placed between 12V supply and ground, clamping transients before they reach LDOs and communication ICs. Use Value: Limits clamped voltage to 22.0 V during 400W pulses, preventing latch-up or permanent damage to 24V-tolerant but 36V-max logic interfaces. |
Use Scenario: Shields isolated flyback or buck converter primary-side controller from reflected surges originating in 24/48V industrial bus lines. IC Role / Device Role / Timing Role: Front-end transient suppressor on input bulk capacitor rail, absorbing energy before it propagates to PWM controller and gate drivers. Use Value: Withstands 18.2A peak impulse at 22.0V clamping, preserving MOSFET VDS rating and enabling use of lower-cost 30V-rated FETs. |
| LED Streetlight Driver | Medical Power Adapter Output |
Use Scenario: Guards constant-current LED driver ICs against lightning-induced surges on outdoor AC/DC input stages operating in harsh ambient conditions. IC Role / Device Role / Timing Role: Secondary-side TVS across output capacitor to clamp residual transients escaping primary-side filtering. Use Value: Delivers 400W pulse handling with <1µA leakage, avoiding standby power penalty while maintaining Class I insulation integrity. |
Use Scenario: Provides secondary-side overvoltage protection on low-noise medical adapter outputs powering sensitive analog sensor circuits. IC Role / Device Role / Timing Role: Final-stage clamping device placed immediately before connector, ensuring patient-connected circuits never exceed safe SELV limits. Use Value: 22.0V clamping voltage guarantees compliance with IEC 60601-1 3rd ed. 2×MOPP creepage/clearance requirements for 12V output rails. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A | Lower VBR range (13.3–14.7 V) and tighter tolerance; VC = 19.9 V at 20.1 A. | Better suited for precision 12V systems requiring lower clamping voltage and reduced overshoot margin. | Select SMAJ12A when clamping voltage headroom is constrained and VBR consistency across temperature is prioritized. |
| P6SMB12CA | Bidirectional variant (CA suffix); same VWM/VBR/VC specs but symmetrical clamping in both polarities. | Required where bidirectional transients (e.g., RS-485 data lines, AC-coupled sensors) must be suppressed. | Choose P6SMB12CA only if dual-polarity protection is needed; SMAJ12C offers superior unidirectional performance and lower cost for DC rail use. |
Compared with SMAJ12A and P6SMB12CA, the SMAJ12C provides optimal unidirectional clamping for 12V DC systems-delivering higher surge current capacity than SMAJ12A at identical VWM, and avoiding unnecessary bidirectional complexity and cost versus P6SMB12CA when polarity is known and controlled.
Availability
SMAJ12C is available at Aetrix Electronics and suitable for automotive body electronics, industrial DC/DC converters, and LED lighting drivers requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ12C 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, specializing in TVS diodes, rectifiers, and power MOSFETs since 1979.
The SMAJ series was developed specifically for high-reliability automotive and industrial transient suppression, emphasizing ISO 7637-2 compliance, tight VBR distribution, and robust DO-214AC packaging for automated SMT lines.
FAQ
What is the polarity configuration of SMAJ12C?
The SMAJ12C is a unidirectional TVS diode, with cathode marked by a band on the DO-214AC package body. It conducts in forward bias up to 3.5V at 25A and clamps reverse transients above its 13.3–16.3V breakdown range. This configuration is ideal for protecting grounded 12V supply rails where only positive-going surges require suppression.
Does SMAJ12C meet automotive EMC standards?
Yes, SMAJ12C is explicitly validated to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test waveforms. Its 400W peak pulse power rating at 10/1000μs, low clamping voltage (22.0V), and stable VBR across temperature make it suitable for front-end protection in BCMs, infotainment power supplies, and ADAS camera modules.
What is the maximum clamping voltage of SMAJ12C under surge conditions?
The SMAJ12C has a maximum clamping voltage (VC) of 22.0 V at 18.2 A peak pulse current (IPPM), measured using the standard 10/1000μs double-exponential waveform. This value is guaranteed across the full operating junction temperature range (–55°C to +150°C) and defines the upper voltage limit imposed on protected circuitry during transient events.
Can SMAJ12C be used in place of SMAJ12A?
SMAJ12C and SMAJ12A are not interchangeable without design review: SMAJ12C has higher VBR (13.3–16.3 V) and VC (22.0 V), while SMAJ12A offers tighter VBR (13.3–14.7 V) and lower VC (19.9 V). Substituting SMAJ12C for SMAJ12A may increase clamping voltage margin but reduce precision in low-overhead 12V systems.
What is the moisture sensitivity level (MSL) of SMAJ12C?
The SMAJ12C is rated MSL Level 1 per J-STD-020, meaning it has unlimited floor life and requires no baking prior to reflow soldering. This simplifies manufacturing logistics and eliminates moisture-related popcorning risk during standard lead-free reflow profiles.
SMAJ12C Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 22V
- Current - Peak Pulse (10/1000µs):
- 18.2A
- 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:
- DO-214AC (SMA)
SMAJ12C FAQ
1.How can I place an order for SMAJ12C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12C 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 SMAJ12C reliable?
The price and inventory of SMAJ12C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12C is usually 5 days.
3.What payment methods are accepted for SMAJ12C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12C?
SMAJ12C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12C 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 SMAJ12C?
For technical support, including SMAJ12C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12C requirements.
6.How does Aetrix verify that SMAJ12C is sourced from the original manufacturer or authorized distributors?
All SMAJ12C 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 SMAJ12C meets industry standards.
7.What is the process for return or replacement of SMAJ12C?
All SMAJ12C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12C, 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 SMAJ12C part is unused and in its original packaging.
Return procedure for SMAJ12C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ12C Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
