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Taiwan Semiconductor Corporation SMAJ20C
- Part No.:
- SMAJ20C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20C.pdf
- Description:
- 400W, 24.7V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:5,910
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Product details
Overview
SMAJ20C from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 20V working stand-off voltage (VWM), 22.2–27.1V breakdown voltage (VBR @ 1mA), and 35.8V maximum clamping voltage (VC) at 11.2A peak pulse current. It protects DC/DC converters and SMPS inputs against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ20C datasheet, SMAJ20C pinout, SMAJ20C application, or SMAJ20C equivalent, key selection criteria include clamping performance under 10/1000μs surge, unidirectional polarity marking, DO-214AC thermal derating above 25°C, and compliance with J-STD-020 Level 1 moisture sensitivity.
Technical Context
The SMAJ20C employs a glass-passivated silicon junction optimized for fast transient response (<1.0ps rise time from 0V to VBR min) and low leakage (<1μA at 20V). Its single-die unidirectional structure provides asymmetric conduction: forward VF = 3.5V at 25A, reverse blocking up to VWM = 20V.
It delivers 400W peak pulse power (10/1000μs waveform) at 25°C, derated linearly above ambient temperature per Fig.2, with maximum junction temperature of 150°C and storage range from –55°C to +150°C. Polarity is indicated by cathode band per DO-214AC mechanical drawing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins; sets system overvoltage trip threshold. |
| VBR @ IT=1mA | 22.2–27.1 V - Breakdown voltage range defining reliable avalanche initiation; ensures consistent turn-on across production lots. |
| VC @ IPPM=11.2A | 35.8 V - Clamping voltage during 10/1000μs surge; determines maximum stress on downstream ICs like controllers or MOSFETs. |
| PPPM | 400 W - Peak pulse power rating at 25°C; defines transient energy absorption capacity without failure. |
| IR @ VWM | <1 μA - Reverse leakage at stand-off voltage; minimizes standby power loss in battery-backed or low-power systems. |
| Package | DO-214AC (SMA) - Surface-mount outline with 0.060g mass, UL 94V-0 molding, matte tin-plated leads, JESD201 Class 2 whisker resistance. |
Pinout & Package
DO-214AC (SMA) package: cathode-marked unidirectional device with two terminals - anode (unmarked end) and cathode (band-marked end). Leads are solderable per J-STD-002; polarity must be observed during PCB layout to ensure correct transient shunting path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink input | Connected to protected line (e.g., 24V rail); conducts surge current toward ground when cathode is held at reference potential. |
| Cathode | Reference node connection | Must be tied to system ground or low-impedance return path; clamping occurs between anode and cathode terminals. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping performance | VC = 35.8V at 11.2A (10/1000μs) ensures downstream 3.3V/5V logic ICs remain below absolute maximum ratings during automotive load dump. |
| Response speed | <1.0ps 0V-to-VBR rise time enables suppression of fast ESD and switching noise before sensitive analog or digital circuitry reacts. |
| Reliability compliance | Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b and J-STD-020 Level 1 moisture sensitivity-validated for automotive and industrial reflow assembly. |
| Thermal robustness | 150°C max junction temperature and 1W steady-state power dissipation support operation in enclosed power supplies without forced cooling. |
Applications
| Automotive Power Input Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 24V vehicle infotainment head unit input against load dump (ISO 7637-2 Pulse 5a) and jump-start surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and DC/DC controller input to clamp transients before they reach regulation circuitry. Use Value: Limits peak voltage to ≤35.8V, preventing latch-up or gate oxide damage in buck controller ICs rated for 40V absolute maximum. |
Use Scenario: Safeguarding isolated 48V-to-12V DC/DC converter primary-side input in factory automation PLCs. IC Role / Device Role / Timing Role: Standoff protection element absorbing repetitive 10/1000μs surges induced by relay coil switching on shared power bus. Use Value: Withstands ≥1000 surges at 50% PPPM without parameter shift, ensuring long-term reliability in high-noise industrial environments. |
| LED Driver Overvoltage Clamp | SMPS Secondary-Side Surge Suppression |
Use Scenario: Preventing catastrophic failure of constant-current LED driver ICs during AC line transients coupled into low-voltage DC output. IC Role / Device Role / Timing Role: Fast-clamping TVS connected across driver output terminals to divert surge current away from LED string and control FETs. Use Value: Sub-1ps response captures nanosecond-scale spikes from nearby motor commutation, avoiding false triggering of driver fault protection. |
Use Scenario: Shielding secondary-side synchronous rectifier MOSFETs and optocoupler feedback circuits in offline flyback SMPS. IC Role / Device Role / Timing Role: Unidirectional suppressor installed between secondary ground and output rail to absorb reflected primary-side transients. Use Value: 20V VWM allows normal 19V output operation while clamping >30V events-preserving regulation accuracy and minimizing output ripple. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20A | Narrower VBR range (22.2–24.5V) and lower VC = 32.4V at 12.3A; same 20V VWM and DO-214AC package. | Better clamping margin for 3.3V/5V logic rails but reduced surge current headroom vs. SMAJ20C's 11.2A rating. | Select SMAJ20A when tighter VBR tolerance and lower clamping voltage are prioritized over peak current handling. |
| 1.5SMC20C | Same VWM = 20V and DO-214AB (SMB) package; higher PPPM = 1500W but larger footprint and 40.5V VC at 37.0A. | Higher power rating suits heavy-duty industrial equipment but requires PCB redesign due to SMB vs. SMA pad layout. | Choose 1.5SMC20C only if system-level surge testing exceeds 400W requirements and board space permits larger package. |
Compared with SMAJ20C, SMAJ20A offers improved clamping consistency at lower surge currents, while 1.5SMC20C trades package compatibility for higher energy absorption-neither is pin-compatible, requiring layout verification for either alternative.
Availability
SMAJ20C is available at Aetrix Electronics and suitable for automotive power input protection, industrial DC/DC converter input hardening, and LED driver overvoltage clamp applications requiring stable component supply across extended production lifecycles.
Supply support for SMAJ20C 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers for automotive, industrial, and consumer markets.
The SMAJ series was designed specifically for robust, surface-mount transient suppression in harsh environments-emphasizing fast response, low leakage, and ISO 7637-2 compliance for 12V/24V vehicle electrical systems.
FAQ
What is the polarity configuration of the SMAJ20C?
The SMAJ20C is a unidirectional TVS diode with clearly marked cathode band per DO-214AC mechanical drawing. Its anode connects to the protected line and cathode to ground, enabling reverse-biased clamping action only-forward conduction occurs at ~3.5V, making it unsuitable for bidirectional signal line protection without external circuitry.
Does the SMAJ20C meet automotive transient immunity standards?
Yes, the SMAJ20C meets ISO 7637-2 Pulse 1 (inductive load disconnect), Pulse 2a (battery feed interruption), Pulse 2b (inductive switch-off), Pulse 3a (capacitive coupling), and Pulse 3b (ground noise) requirements. Its 400W peak pulse rating and sub-1ps response time are validated for 12V/24V automotive subsystems per TSC U2102 specification.
How does the SMAJ20C's clamping voltage compare to its breakdown voltage?
The SMAJ20C has a VBR range of 22.2–27.1V at 1mA test current and clamps to 35.8V at 11.2A (10/1000μs). This 8.7–13.6V differential reflects the dynamic impedance of the avalanche junction under surge conditions-critical for ensuring downstream components see voltage stress within safe operating limits.
Can the SMAJ20C be used in bidirectional signal lines?
No, the SMAJ20C is unidirectional and not rated for bidirectional operation. For AC or dual-polarity signal lines, use the SMAJ20CA variant (bidirectional version with symmetric VBR and VC in both directions) or pair two SMAJ20C devices in series opposition-though the latter increases capacitance and requires careful layout to avoid imbalance.
What is the maximum operating temperature for the SMAJ20C?
The SMAJ20C has a maximum junction temperature (TJMAX) of 150°C and operates across –55°C to +150°C. At ambient temperatures above 25°C, its 400W peak pulse power rating must be derated per Fig.2 in the TSC U2102 datasheet-e.g., 200W at 75°C ambient-to prevent thermal runaway during repeated surge events.
SMAJ20C 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:
- 35.8V
- Current - Peak Pulse (10/1000µs):
- 11.2A
- 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)
SMAJ20C FAQ
1.How can I place an order for SMAJ20C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20C 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 SMAJ20C reliable?
The price and inventory of SMAJ20C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20C is usually 5 days.
3.What payment methods are accepted for SMAJ20C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20C?
SMAJ20C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20C 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 SMAJ20C?
For technical support, including SMAJ20C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20C requirements.
6.How does Aetrix verify that SMAJ20C is sourced from the original manufacturer or authorized distributors?
All SMAJ20C 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 SMAJ20C meets industry standards.
7.What is the process for return or replacement of SMAJ20C?
All SMAJ20C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20C, 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 SMAJ20C part is unused and in its original packaging.
Return procedure for SMAJ20C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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