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Taiwan Semiconductor Corporation SMAJ20AH
- Part No.:
- SMAJ20AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20AH.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,835
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Product details
Overview
SMAJ20AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 20 V working stand-off voltage (VWM), 22.2–24.5 V breakdown voltage (VBR) at 1 mA test current, and clamps transients to ≤32.4 V at 12.3 A peak impulse current under 10/1000 µs waveform - ideal for protecting automotive-grade DC/DC converters against ISO 7637-2 Pulse 1/2a/2b/3a/3b surges.
For engineers reviewing the SMAJ20AH datasheet, SMAJ20AH pinout, SMAJ20AH application, or SMAJ20AH equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, clamping performance under standardized surge waveforms, moisture sensitivity level (MSL 1), and RoHS/halogen-free compliance - all critical for automotive and industrial power supply design validation.
Technical Context
The SMAJ20AH operates as a unidirectional avalanche diode with glass-passivated junction, enabling fast response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at 20 V). Its single-die configuration in DO-214AC package supports automated placement and meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements.
It delivers 400 W peak pulse power (10/1000 µs) up to 78 V VWM, derating linearly above 25 °C ambient per Fig.2; maximum junction temperature is 150 °C, with operating range from –55 °C to +150 °C. Polarity is marked by cathode band on the package body.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - maximum continuous reverse voltage before significant leakage; sets safe operating margin below system rail voltage |
| VBR min/max | 22.2 V / 24.5 V @ 1 mA - guaranteed avalanche initiation window ensures consistent turn-on across production lots |
| VC @ IPPM | ≤32.4 V @ 12.3 A - clamping voltage during 10/1000 µs surge defines protected circuit's maximum transient stress |
| PPPM | 400 W (10/1000 µs) - peak surge energy handling capacity for automotive load-dump and inductive switching events |
| IR @ VWM | ≤1 µA - ultra-low reverse leakage preserves efficiency in high-impedance sensing or battery-backed circuits |
| TJ max | +150 °C - enables reliable operation in under-hood automotive environments and enclosed industrial enclosures |
| MSL | Level 1 (per J-STD-020) - no floor life limitation; supports standard reflow without baking preconditioning |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, cathode indicated by band marking; polarity-critical for unidirectional operation; weight ≈ 0.060 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; determines forward conduction path during surge |
| Cathode | Protected line input | Connected to the line being protected (e.g., 24 V rail); avalanche conduction occurs from cathode to anode during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TCT, ESD, and mechanical shock |
| Glass passivated junction | Enhances long-term reliability and stability of breakdown voltage under thermal cycling and humidity exposure |
| Fast response time | <1.0 ps rise-to-breakdown ensures suppression before sensitive downstream ICs experience overstress |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) immunity requirements |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive - supports green manufacturing and end-of-life recycling |
Applications
| Automotive DC/DC Converter Protection | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protects 24 V input stage of buck converter in engine control unit (ECU) against load-dump transients up to ±120 V. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between VIN and GND, absorbing energy before it reaches controller IC and MOSFET gate drivers. Use Value: Limits voltage seen by downstream components to ≤32.4 V during 12.3 A surge, preventing latch-up or oxide breakdown in 3.3 V/5 V logic supplies. | Use Scenario: Shields primary-side rectifier and PWM controller in 48 V telecom SMPS from line-induced surges and switching noise. IC Role / Device Role / Timing Role: Standoff-rated TVS placed across bulk capacitor input, conducting only during transient excursions exceeding 20 V. Use Value: Maintains <1 µA leakage at 20 V, avoiding unnecessary power loss while delivering 400 W surge absorption without derating below 78 V. |
| LED Driver Overvoltage Clamp | On-Board Charger (OBC) Auxiliary Rail |
Use Scenario: Safeguards constant-current LED driver ICs in vehicle lighting modules from battery reversal and jump-start spikes. IC Role / Device Role / Timing Role: Cathode tied to LED string anode, anode to chassis ground - conducts during positive transients on supply line. Use Value: Clamps 10/1000 µs surges to ≤32.4 V, preserving driver IC integrity and enabling MSL Level 1 reflow compatibility for SMT assembly. | Use Scenario: Protects 12 V auxiliary supply rail in electric vehicle on-board charger during CAN bus coupling events and relay bounce. IC Role / Device Role / Timing Role: TVS placed at LDO input to absorb coupled transients from high-power switching stages. Use Value: Leverages AEC-Q101 qualification and –55 °C to +150 °C operation to ensure reliability across full EV thermal envelope. |
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 | Same VWM (20 V), but lower VBR min (20.0 V vs. 22.2 V); identical DO-214AC package and 400 W rating | Lower clamping threshold may trigger earlier in marginal overvoltage conditions; suitable where tighter VBR tolerance is required | Select SMAJ20A if earlier conduction onset is needed; SMAJ20AH preferred for higher surge margin due to elevated VBR window |
| SMBJ20AH | Same electrical specs but in larger DO-214AA (SMB) package; 600 W peak power rating (vs. 400 W) | Higher power handling supports longer-duration transients; requires PCB layout change due to larger footprint and lead pitch | Choose SMBJ20AH when surge duration exceeds 10/1000 µs capability or when thermal dissipation demands larger package |
Compared with SMAJ20A and SMBJ20AH, the SMAJ20AH balances precise VBR control (22.2–24.5 V), industry-standard 400 W surge rating, and compact DO-214AC footprint - making it optimal for space-constrained automotive modules requiring AEC-Q101 validation and MSL Level 1 process compatibility.
Availability
SMAJ20AH is available at Aetrix Electronics and suitable for automotive ECUs, industrial SMPS designs, LED lighting systems, and on-board chargers requiring stable component supply with AEC-Q101 qualification and halogen-free compliance.
Supply support for SMAJ20AH 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, MOSFETs, and power management devices.
The SMAJ series was developed specifically for automotive and industrial transient suppression, emphasizing AEC-Q101 reliability, ISO 7637-2 compliance, and surface-mount manufacturability in compact DO-214AC packaging.
FAQ
What is the maximum clamping voltage of the SMAJ20AH under standard surge conditions?
The SMAJ20AH has a maximum clamping voltage (VC) of 32.4 V when subjected to its rated peak impulse current of 12.3 A under the 10/1000 µs waveform. This value is measured at the device terminals and represents the highest voltage that will appear across the SMAJ20AH during a standardized transient event - critical for ensuring downstream ICs remain within absolute maximum ratings.
Is the SMAJ20AH suitable for bidirectional transient protection?
No, the SMAJ20AH is a unidirectional TVS diode, intended for protection against positive-going transients on a referenced DC line. For bidirectional applications, Taiwan Semiconductor offers the SMAJ20CH or SMAJ20CAH variants, which feature symmetrical breakdown in both directions and use different marking codes and suffixes.
Does the SMAJ20AH require special handling during PCB assembly?
No - the SMAJ20AH is rated MSL Level 1 per J-STD-020, meaning it has unlimited floor life and can be processed using standard SnPb or Pb-free reflow profiles without pre-baking. Its matte tin-plated leads comply with J-STD-002 for solderability, and the DO-214AC package supports high-speed automated placement.
How does the SMAJ20AH meet automotive electromagnetic compatibility requirements?
The SMAJ20AH is explicitly tested and compliant with ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive switch-off), Pulse 2a/2b (battery interruption), and Pulse 3a/3b (capacitive coupling). Its fast response (<1.0 ps), low clamping voltage, and AEC-Q101 qualification collectively ensure robust EMC performance in vehicle power networks.
What is the difference between SMAJ20AH and SMAJ20H?
The SMAJ20AH has a tighter breakdown voltage range (22.2–24.5 V) compared to SMAJ20H (22.2–27.1 V), resulting in more consistent clamping behavior and reduced variation in surge turn-on threshold. Both share identical VWM (20 V), package (DO-214AC), and peak power rating (400 W), but SMAJ20AH is preferred where tighter VBR control improves system-level surge margin predictability.
SMAJ20AH 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:
- 1
- Bidirectional Channels:
- -
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ20AH FAQ
1.How can I place an order for SMAJ20AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20AH 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 SMAJ20AH reliable?
The price and inventory of SMAJ20AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20AH is usually 5 days.
3.What payment methods are accepted for SMAJ20AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20AH?
SMAJ20AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20AH 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 SMAJ20AH?
For technical support, including SMAJ20AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20AH requirements.
6.How does Aetrix verify that SMAJ20AH is sourced from the original manufacturer or authorized distributors?
All SMAJ20AH 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 SMAJ20AH meets industry standards.
7.What is the process for return or replacement of SMAJ20AH?
All SMAJ20AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20AH, 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 SMAJ20AH part is unused and in its original packaging.
Return procedure for SMAJ20AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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