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Taiwan Semiconductor Corporation SMAJ20CA
- Part No.:
- SMAJ20CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20CA.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,052
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Product details
Overview
SMAJ20CA from Taiwan Semiconductor is a bidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 20V working stand-off voltage (VWM), 22.2–24.5V breakdown voltage (VBR), and 32.4V maximum clamping voltage (VC) at 12.3A peak pulse current. It protects DC/DC converters and automotive power rails against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ20CA datasheet, SMAJ20CA pinout, SMAJ20CA application, or SMAJ20CA equivalent, this page delivers verified electrical parameters, bidirectional TVS behavior, DO-214AC mechanical data, clamping performance under 10/1000μs waveform, and direct alternatives for overvoltage protection design.
Technical Context
The SMAJ20CA is a glass-passivated, bipolar junction TVS diode optimized for fast transient suppression in automotive and industrial power systems. Its bidirectional configuration enables symmetrical clamping in AC-coupled or floating-rail applications without polarity sensitivity.
It delivers 400W peak pulse power (10/1000μs waveform) up to 78V VWM, derating linearly above 25°C ambient per Fig.2, and maintains <1μA reverse leakage at 20V - critical for low-power standby circuits. The device meets ISO 7637-2 compliance for automotive load-dump and inductive-switching immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin. |
| VBR @ IT=1mA | 22.2–24.5 V - Breakdown threshold range; ensures reliable turn-on during surge events without premature conduction. |
| VC @ IPPM=12.3A | 32.4 V - Clamped voltage under 400W 10/1000μs pulse; limits downstream IC stress to safe levels. |
| PPPM | 400 W - Peak pulse power rating; supports robust protection against high-energy transients like load dump. |
| IR @ VWM | <1 μA - Ultra-low leakage at rated stand-off voltage; preserves battery life in always-on systems. |
| TJ Range | −55 to +150 °C - Full automotive temperature operation; validated for under-hood and engine-control module use. |
Pinout & Package
DO-214AC (SMA) surface-mount package: cathode-banded monolithic bidirectional TVS diode with matte tin-plated leads, UL 94V-0 molding compound, and JESD201 Class 2 whisker resistance. Polarity marked by band; no anode/cathode distinction required for bidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Transient current entry point (bidirectional) | Accepts surge current in either polarity; symmetric clamping behavior eliminates orientation dependency. |
| Cathode (banded end) | Transient current exit point (bidirectional) | Completes low-impedance path to ground/rail during clamping; band serves as visual mounting reference only. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection on floating or AC-coupled lines without polarity constraints or external diode pairing. |
| Fast response time <1 ps | Clamps transients before sensitive logic or analog circuitry experiences overvoltage damage - critical for CAN, LIN, and sensor interfaces. |
| ISO 7637-2 compliance | Validated for automotive Pulse 1 (inductive switch-off), Pulse 2a/2b (battery disconnect), and Pulse 3a/3b (capacitive coupling) - reduces qualification testing effort. |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; compatible with standard SMT assembly lines without special handling. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
Use Scenario: Protects 24V supply rail of BCM microcontroller and CAN transceivers from load-dump and jump-start transients. IC Role / Device Role / Timing Role: Bidirectional TVS clamp placed directly at power entry point before EMI filter and LDO. Use Value: Limits rail voltage to ≤32.4V during 400W pulses, preventing latch-up or permanent damage to 3.3V/5V logic and transceivers. | Use Scenario: Shields 24V digital input channels from field-wiring induced surges and relay coil flyback. IC Role / Device Role / Timing Role: Primary overvoltage protection element across input terminals, upstream of optocoupler or Schmitt trigger. Use Value: Sub-1ps response ensures clamping occurs before 100ns edge rates propagate into isolation barrier, maintaining signal integrity. |
| LED Streetlight Driver | On-board DC/DC Converter (12V→3.3V) |
Use Scenario: Guards primary-side MOSFET gate driver and controller IC against lightning-induced surges on AC mains input. IC Role / Device Role / Timing Role: Secondary-level TVS placed across bulk capacitor or across transformer primary winding. Use Value: 400W rating handles repetitive line surges per IEC 61000-4-5 Level 3; 20V VWM avoids conduction during normal 12V/24V nominal operation. | Use Scenario: Safeguards buck converter IC and feedback resistors from output-side transients reflected through inductor or coupled via layout. IC Role / Device Role / Timing Role: Localized TVS across output rail, adjacent to load connector or hot-swap FET. Use Value: 32.4V clamping prevents overvoltage on 3.3V LDO input and MCU VDD pins during hot-plug or cable discharge events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ20CA (Bourns) | Same VWM/VC specs but 600W PPPM (10/1000μs); larger SMB package (DO-214AA). | Higher power handling suits higher-energy automotive transients; requires PCB footprint change. | Select when system-level surge tests exceed 400W or when longer pulse durations demand higher energy absorption. |
| P6SMB20CA (Littelfuse) | Identical VWM, VBR, VC, and PPPM; same DO-214AC package; RoHS/halogen-free compliant. | No functional or mechanical deviation; qualified for identical ISO 7637-2 test profiles. | Drop-in replacement with full pin-to-pin and form-fit compatibility; preferred for dual-sourcing in automotive production. |
Compared with SMBJ20CA and P6SMB20CA, the SMAJ20CA offers optimal cost-performance balance for 400W-class protection in space-constrained DO-214AC layouts, while P6SMB20CA provides seamless second-source continuity without redesign.
Availability
SMAJ20CA is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, LED driver front-ends, and on-board DC/DC converters requiring stable component supply across extended temperature and high-reliability environments.
Supply support for SMAJ20CA 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMAJ series is designed specifically for high-reliability transient suppression in harsh environments - emphasizing ISO 7637-2 compliance, moisture resilience, and stable clamping across −55°C to +150°C.
FAQ
What is the clamping voltage of SMAJ20CA at its rated peak pulse current?
The SMAJ20CA has a maximum clamping voltage (VC) of 32.4 V at 12.3 A peak pulse current (IPPM), measured under the standard 10/1000μs waveform. This value ensures downstream components see limited overvoltage stress during surge events. The SMAJ20CA's low clamping ratio (VC/VBR ≈ 1.32) reflects efficient energy diversion without excessive voltage overshoot.
Is SMAJ20CA unidirectional or bidirectional, and how does that affect circuit placement?
SMAJ20CA is a bidirectional TVS diode, indicated by the "CA" suffix. It clamps symmetrically in both polarities, eliminating the need to observe anode/cathode orientation during placement. This simplifies layout on floating nodes, AC-coupled lines, or differential buses like CAN, where polarity reversal is possible. The SMAJ20CA functions identically regardless of voltage polarity across its terminals.
Does SMAJ20CA meet automotive transient immunity standards?
Yes, SMAJ20CA meets ISO 7637-2 requirements for Pulses 1, 2a, 2b, 3a, and 3b - covering key automotive transients including load dump, battery disconnection, and inductive switching. Its 400W peak pulse power rating, −55°C to +150°C operating range, and moisture sensitivity level 1 make it suitable for under-hood and body-control applications. The SMAJ20CA is explicitly validated for these test profiles per TSC documentation.
What is the reverse leakage current of SMAJ20CA at its working stand-off voltage?
At its 20 V working stand-off voltage (VWM), the SMAJ20CA exhibits a maximum reverse leakage current (IR) of 1 μA at 25°C. This ultra-low leakage preserves power efficiency in always-on systems such as automotive wake-up circuits or IoT sensor nodes. The SMAJ20CA maintains this specification across its full operating temperature range, supporting reliable low-power design.
Can SMAJ20CA be used in place of SMAJ20A, and what is the key difference?
No - SMAJ20CA and SMAJ20A are functionally distinct. SMAJ20CA is bidirectional (CA = Common Anode, i.e., symmetrical), while SMAJ20A is unidirectional (A = Asymmetric). SMAJ20A clamps only in reverse bias and conducts forward current like a rectifier; SMAJ20CA clamps equally in both directions. Substituting one for the other risks failure in AC or floating-rail applications. Always verify polarity requirements before selecting SMAJ20CA or SMAJ20A.
SMAJ20CA 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 12.3A
- 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)
SMAJ20CA FAQ
1.How can I place an order for SMAJ20CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20CA 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 SMAJ20CA reliable?
The price and inventory of SMAJ20CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20CA is usually 5 days.
3.What payment methods are accepted for SMAJ20CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20CA?
SMAJ20CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20CA 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 SMAJ20CA?
For technical support, including SMAJ20CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20CA requirements.
6.How does Aetrix verify that SMAJ20CA is sourced from the original manufacturer or authorized distributors?
All SMAJ20CA 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 SMAJ20CA meets industry standards.
7.What is the process for return or replacement of SMAJ20CA?
All SMAJ20CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20CA, 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 SMAJ20CA part is unused and in its original packaging.
Return procedure for SMAJ20CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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