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Taiwan Semiconductor Corporation SMF20AH
- Part No.:
- SMF20AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF20AH.pdf
- Description:
- TVS DIODE 20VWM 32.4VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:3,674
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Product details
Overview
SMF20AH from Taiwan Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for automotive-grade circuit protection. It features a 20 V working stand-off voltage (VWM), 22.2–24.5 V breakdown voltage (VBR), 32.4 V clamping voltage (VC) at 6.2 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It is AEC-Q101 qualified and used to protect automotive lighting and ECU power rails against ISO 7637-2 pulses.
For engineers reviewing the SMF20AH datasheet, SMF20AH pinout, SMF20AH application, or SMF20AH equivalent, key selection criteria include clamping performance under 10/1000 µs transients, low leakage (<1 µA @ 20 V), SOD-123W package compatibility with automated assembly, and compliance with automotive immunity standards including Pulse 1, 2a, 2b, 3a, and 3b.
Technical Context
The SMF20AH operates as a unidirectional avalanche diode, conducting only in reverse bias above its breakdown threshold to shunt transient energy away from protected ICs. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low leakage (<1 µA at VWM), critical for low-power automotive sensors and CAN/LIN bus interfaces.
Thermal design is enabled by its SOD-123W package with RθJA = 100 °C/W and RθJL = 33 °C/W on a 5 mm × 5 mm Cu pad, supporting reliable operation up to TJ = 175 °C. It meets ISO 7637-2 test conditions without external series impedance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT = 1 mA | 22.2–24.5 V - Confirmed avalanche onset range; ensures predictable turn-on margin over VWM |
| VC @ IPPM = 6.2 A | 32.4 V - Clamped voltage during 10/1000 µs transient; defines maximum stress on downstream IC |
| PPPM (10/1000 µs) | 200 W - Peak surge handling capacity; supports ISO 7637-2 Pulse 1 (inductive load dump) immunity |
| IR @ VWM | <1 µA - Negligible standby leakage; avoids battery drain in always-on automotive modules |
| Package | SOD-123W - Surface-mount outline with matte tin leads; compatible with J-STD-002 soldering and JESD 201 Class 2 whisker resistance |
| AEC-Q101 | Qualified - Validated for automotive temperature cycling, humidity, and mechanical stress per AEC standard |
Pinout & Package
SMF20AH uses the SOD-123W package: a compact, gull-wing surface-mount outline with cathode band marking polarity. Dimensions comply with JEDEC TO-236AB and support high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction path / low-side reference | Connected to ground or low-impedance return path; forms current loop during clamping |
| Cathode | Protected line input / high-side connection | Connected to supply rail or signal line being protected; reverse-biased during normal operation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood environments: -40°C to +125°C case temperature, thermal shock, and vibration |
| Photo glass passivation | Stable VBR over lifetime and humidity exposure; prevents parametric drift in harsh automotive climates |
| Clamping ratio VC/VBR | 1.31–1.46 - Tight ratio ensures minimal overvoltage overshoot during fast transients |
| Moisture sensitivity level | MSL Level 1 (per J-STD-020) - No floor life limitation; safe for standard SMT reflow without baking |
| ISO 7637-2 compliance | Tested for Pulses 1, 2a, 2b, 3a, 3b - Enables single-device protection of 12 V automotive power networks |
Applications
| Automotive Lighting Control | Body Control Module (BCM) Power Input |
|---|---|
Use Scenario: Protecting LED driver ICs from load-dump transients during headlamp switching in 12 V systems. IC Role / Device Role: Unidirectional TVS placed between battery rail and LDO input to clamp ISO 7637-2 Pulse 1 (−100 V, 40 ms). Use Value: Limits voltage seen by downstream regulators to ≤32.4 V, preventing latch-up or permanent damage to 36 V-rated ICs. | Use Scenario: Safeguarding microcontroller power inputs in BCMs exposed to alternator ripple and ignition noise. IC Role / Device Role: Reverse-biased TVS across VCC and GND to suppress EFT bursts (IEC 61000-4-4) and coupled transients. Use Value: Sub-1 µA leakage preserves sleep-mode current budget; 200 W rating handles repetitive 10/1000 µs surges without degradation. |
| Infotainment Display Backlight | Door Module Window Motor Driver |
Use Scenario: Shielding DC-DC converter feedback resistors and PWM controllers in LCD backlight circuits. IC Role / Device Role: Low-capacitance TVS on 5 V or 12 V bias lines to prevent false triggering from ESD events near display bezels. Use Value: 32.4 V clamping ensures feedback nodes remain within ADC input range; SOD-123W footprint minimizes board area. | Use Scenario: Protecting H-bridge gate drivers from inductive kickback when reversing window motor direction. IC Role / Device Role: Unidirectional TVS on motor supply rail to absorb flyback energy during MOSFET turn-off. Use Value: 22.2–24.5 V VBR provides sufficient margin above 13.5 V nominal battery, while 200 W PPPM sustains repeated actuation cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ20A | Same VWM (20 V), slightly higher VC (34.0 V), same SOD-123 package but non-AEC-Q101 rated | Not qualified for automotive use; suitable for industrial or consumer power supplies only | Select SMAJ20A only if AEC-Q101 is not required and clamping voltage margin allows |
| Vishay SMBJ20A | Same VWM and VC (32.4 V), AEC-Q101 qualified, but SMB package (larger footprint, higher RθJA = 125 °C/W) | Requires PCB layout change; better thermal mass but lower power density than SOD-123W | Choose SMBJ20A when higher steady-state power dissipation (>1 W) or enhanced surge robustness is needed |
Compared with SMAJ20A and SMBJ20A, the SMF20AH delivers identical electrical protection in a smaller, automotive-qualified SOD-123W package-enabling tighter layout control and compliance with OEM component requirements without sacrificing clamping performance or reliability.
Availability
SMF20AH is available at Aetrix Electronics and suitable for automotive lighting control, body control module (BCM) power input, infotainment display backlight, and door module window motor driver applications requiring stable component supply and full AEC-Q101 traceability.
Supply support for SMF20AH 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 devices for automotive and industrial markets.
The SMF series was developed specifically to meet stringent AEC-Q101 and ISO 7637-2 requirements for 12 V automotive power networks, emphasizing low leakage, tight VBR tolerance, and repeatable clamping performance under thermal stress.
FAQ
What is the maximum clamping voltage of the SMF20AH under standard test conditions?
The SMF20AH has a maximum clamping voltage (VC) of 32.4 V when subjected to a 10/1000 µs waveform with a peak pulse current (IPPM) of 6.2 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. The SMF20AH maintains this clamping performance across its qualified operating temperature range, making it suitable for automotive environments where voltage overshoot must be tightly controlled.
Is the SMF20AH suitable for bidirectional transient protection?
No, the SMF20AH is a unidirectional TVS diode and is not designed for bidirectional protection. Its electrical specifications-including breakdown voltage, clamping behavior, and test conditions-are defined only for reverse-bias operation. For applications requiring protection against both positive and negative transients (e.g., data lines), a bidirectional variant such as SMF20A or a dedicated bidirectional TVS must be selected instead of the SMF20AH.
Does the SMF20AH require derating at elevated ambient temperatures?
Yes, the SMF20AH's peak pulse power (PPPM) must be derated above TA = 25°C per Figure 2 in the official datasheet. At 85°C ambient, PPPM is reduced to approximately 140 W; at 125°C, it drops to ~90 W. This derating ensures junction temperature remains within the 175°C absolute maximum. Designers must apply thermal modeling or consult the derating curve to confirm safe operation in high-temperature automotive locations like engine compartments.
What is the marking code printed on the SMF20AH device body?
The SMF20AH is marked with the code "2W020" on its package surface. This 5-character alphanumeric code identifies the specific voltage variant within the SMF family and is visible under magnification on the SOD-123W casing. The marking follows Taiwan Semiconductor's standardized format where "2W" denotes the SMF series and "020" indicates the 20 V working stand-off rating. No additional date or factory codes are part of the base marking for identification purposes.
How does the SMF20AH compare to the SMAJ20A in terms of automotive qualification?
The SMF20AH is AEC-Q101 qualified, whereas the SMAJ20A is not certified to this automotive reliability standard. This means the SMF20AH has undergone extended stress testing-including temperature cycling, humidity bias, and mechanical shock-to validate performance in automotive under-hood and cabin environments. The SMAJ20A lacks this validation and is intended for commercial or industrial use only; using it in automotive designs may risk field failure and non-compliance with OEM component requirements.
SMF20AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- SOD-123W
- Series:
- SMF
- 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):
- 6.2A
- Power - Peak Pulse:
- 200W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123W
SMF20AH FAQ
1.How can I place an order for SMF20AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF20AH 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 SMF20AH reliable?
The price and inventory of SMF20AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF20AH is usually 5 days.
3.What payment methods are accepted for SMF20AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF20AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF20AH?
SMF20AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF20AH 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 SMF20AH?
For technical support, including SMF20AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF20AH requirements.
6.How does Aetrix verify that SMF20AH is sourced from the original manufacturer or authorized distributors?
All SMF20AH 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 SMF20AH meets industry standards.
7.What is the process for return or replacement of SMF20AH?
All SMF20AH units undergo pre-shipment inspection (PSI). If there is an issue with SMF20AH, 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 SMF20AH part is unused and in its original packaging.
Return procedure for SMF20AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF20AH Tags
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