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Taiwan Semiconductor Corporation SMF40AH
- Part No.:
- SMF40AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF40AH.pdf
- Description:
- TVS DIODE 40VWM 64.5VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:9,770
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Product details
Overview
SMF40AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SOD-123W package, with 40 V working stand-off voltage (VWM), 44.4–49.1 V breakdown voltage (VBR), 64.5 V clamping voltage (VC) at 3.1 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It protects automotive and industrial power rails against ISO 7637-2 pulses and ESD transients.
For engineers reviewing the SMF40AH datasheet, SMF40AH pinout, SMF40AH application, or SMF40AH equivalent, key selection criteria include clamping performance under 10/1000 µs surge, low leakage (<1 µA above 10 V), AEC-Q101 qualification, moisture sensitivity level 1 compliance, and SOD-123W footprint compatibility with automated PCB assembly.
Technical Context
The SMF40AH operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified breakdown range (44.4–49.1 V at 1 mA test current). Its clamping action limits transient-induced overvoltage to ≤64.5 V at 3.1 A, enabling robust protection of downstream 3.3 V/5 V/12 V logic and power ICs.
Designed for automotive-grade reliability, it meets AEC-Q101 stress testing requirements and ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b immunity standards. Thermal performance includes RθJL = 33 °C/W and RθJA = 100 °C/W on a 5 mm × 5 mm copper pad, supporting sustained operation up to TJ = 175 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 44.4 V / 49.1 V - Breakdown occurs within this range at 1 mA, defining turn-on threshold tolerance |
| VC @ IPPM | 64.5 V - Clamped voltage during 3.1 A 10/1000 µs surge, limiting stress on protected circuitry |
| PPPM | 200 W - Peak surge power handling capability per standard 10/1000 µs waveform |
| IR @ VWM | <1 µA - Reverse leakage at 40 V ensures minimal standby power loss in battery-powered systems |
| TJ max | +175 °C - Enables use in under-hood automotive environments and high-temperature industrial enclosures |
| Package | SOD-123W - Surface-mount outline with matte tin-plated leads, J-STD-002 solderable, MSL Level 1 |
Pinout & Package
SOD-123W is a two-terminal surface-mount package with cathode band marking polarity. The device has no internal connections beyond anode and cathode; terminals are optimized for high-current surge conduction and thermal dissipation via PCB copper pads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to system ground or low-side return path; enables unidirectional clamping from cathode to anode |
| Cathode | Transient voltage sensing and clamping node | Connected to protected line (e.g., 12 V rail); conducts surge current to ground when VREV > VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTGB, HTRB, and temperature cycling |
| Photo glass passivated junction | Enhances long-term reliability and stability of breakdown voltage under humidity and thermal cycling |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Provides certified immunity against load dump, alternator ripple, and inductive switching transients in 12 V vehicle systems |
| Moisture Sensitivity Level 1 | Enables direct placement without baking; supports high-volume SMT manufacturing with zero floor life restrictions |
| RoHS & halogen-free | Complies with IEC 61249-2-21 and EU RoHS Directive, suitable for green electronics manufacturing |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12 V supply lines in body control modules against load dump and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between power rail and chassis ground to clamp surges above 40 V. Use Value: Limits voltage to ≤64.5 V during 3.1 A transients, preventing damage to MCU power inputs and CAN transceivers. | Use Scenario: Safeguarding analog sensor outputs (e.g., pressure, temperature) connected to PLC input cards. IC Role / Device Role / Timing Role: Transient suppression at signal line entry point to prevent latch-up or ESD-induced failure. Use Value: Sub-1 µA leakage preserves signal integrity; 64.5 V clamping prevents overvoltage on 24 V sensor supply paths. |
| LED Driver Input Protection | USB-C Power Delivery Line Protection |
Use Scenario: Shielding constant-current LED drivers from inductive kickback in automotive lighting systems. IC Role / Device Role / Timing Role: Parallel-connected TVS on DC input to absorb energy from relay or MOSFET switching events. Use Value: 200 W peak pulse rating handles repetitive 10/1000 µs surges without degradation; SOD-123W fits tight board space. | Use Scenario: Protecting 20 V USB-C PD bus lines from ESD and fast transients during hot-plug events. IC Role / Device Role / Timing Role: Primary clamping device on VBUS line upstream of buck converter and port controller. Use Value: 40 V VWM allows safe operation across full USB-C PD profile; 64.5 V VC ensures downstream ICs remain within absolute maximum ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A | Same VWM (40 V), but higher VC = 64.8 V; lower PPPM = 400 W (vs. SMF40AH's 200 W); SMA package (larger footprint) | Higher thermal mass suits higher-energy surges; less suitable for dense automotive PCB layouts | Select SMAJ40A only if board space permits larger SMA package and higher clamping margin is acceptable |
| 1.5SMC40A | Same VWM and VC (64.5 V), but 1500 W PPPM; DO-214AB package; higher IR (5 µA vs. <1 µA) | Used in industrial AC/DC front-ends where higher surge energy must be absorbed | Choose 1.5SMC40A for mains-connected equipment; avoid in battery-sensitive or space-constrained designs |
Compared with SMAJ40A and 1.5SMC40A, the SMF40AH offers optimal balance of compact SOD-123W size, ultra-low leakage, AEC-Q101 qualification, and precise 64.5 V clamping-making it preferred for automotive infotainment, ADAS sensors, and embedded controllers where footprint, reliability, and low standby current are critical.
Availability
SMF40AH is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and LED driver input surge suppression requiring stable component supply and AEC-Q101-compliant sourcing.
Supply support for SMF40AH 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, rectifiers, and MOSFETs, with global distribution and AEC-Q101-certified product lines.
The SMF series was developed specifically for automotive and industrial transient protection, emphasizing low-profile packaging, high surge robustness, and compliance with ISO 7637-2 and AEC-Q101 standards.
FAQ
What is the clamping voltage of the SMF40AH under standard surge conditions?
The SMF40AH exhibits a maximum clamping voltage (VC) of 64.5 V when subjected to a 10/1000 µs surge waveform at its rated peak pulse current of 3.1 A. This value is measured per JEDEC standards and ensures protected circuits remain within safe operating limits during transient events such as load dump or ESD.
Is the SMF40AH suitable for automotive applications?
Yes, the SMF40AH is AEC-Q101 qualified and explicitly designed for automotive use. It meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements and operates reliably from −55 °C to +175 °C junction temperature-making it appropriate for engine control units, body electronics, and ADAS sensor modules.
What package type does the SMF40AH use, and is it compatible with standard SMT processes?
The SMF40AH uses the SOD-123W package, featuring matte tin-plated leads compliant with J-STD-002 solderability standards and moisture sensitivity level 1 (MSL-1). It is fully compatible with automated pick-and-place and reflow soldering processes without pre-baking.
How does the SMF40AH compare to the SMF36AH or SMF43AH in terms of voltage rating?
The SMF40AH has a 40 V working stand-off voltage (VWM), placing it between SMF36AH (36 V) and SMF43AH (43 V). Its breakdown voltage range is 44.4–49.1 V, offering tighter margin over 40 V rails than SMF36AH while providing lower clamping than SMF43AH-ideal for 36–42 V nominal systems like 48 V mild-hybrid architectures.
Does the SMF40AH have unidirectional or bidirectional configuration?
The SMF40AH is a unidirectional TVS diode, intended for DC line protection where polarity is fixed. Its datasheet specifies uni-directional breakdown characteristics, cathode-band polarity marking, and forward voltage (VF = 3.5 V @ 12 A), confirming single-quadrant operation-unlike bidirectional variants used in AC or differential signal lines.
SMF40AH 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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 3.1A
- 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
SMF40AH FAQ
1.How can I place an order for SMF40AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF40AH 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 SMF40AH reliable?
The price and inventory of SMF40AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF40AH is usually 5 days.
3.What payment methods are accepted for SMF40AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF40AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF40AH?
SMF40AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF40AH 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 SMF40AH?
For technical support, including SMF40AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF40AH requirements.
6.How does Aetrix verify that SMF40AH is sourced from the original manufacturer or authorized distributors?
All SMF40AH 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 SMF40AH meets industry standards.
7.What is the process for return or replacement of SMF40AH?
All SMF40AH units undergo pre-shipment inspection (PSI). If there is an issue with SMF40AH, 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 SMF40AH part is unused and in its original packaging.
Return procedure for SMF40AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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