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Taiwan Semiconductor Corporation SMA4F20AH
- Part No.:
- SMA4F20AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA4F20AH.pdf
- Description:
- 400W, 23.6V, 5%, UNIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:9,383
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Product details
Overview
SMA4F20AH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with a 20V working stand-off voltage, 22.4–24.7V breakdown voltage at 1mA, and 32.5V clamping voltage at 12.3A peak pulse current; used for overvoltage protection in automotive BLDC motor drives and battery management systems.
For engineers reviewing the SMA4F20AH datasheet, SMA4F20AH pinout, SMA4F20AH application, or SMA4F20AH equivalent, key selection criteria include its AEC-Q101 qualification, 175°C maximum junction temperature, 20°C/W junction-to-lead thermal resistance, unidirectional polarity, and Thin SMA package compatibility with J-STD-002 solderability requirements.
Technical Context
This TVS diode employs a glass-passivated silicon junction optimized for fast response to transients up to 10/1000μs waveform, delivering 400W non-repetitive peak pulse power dissipation while maintaining low leakage (<1μA at 20V) and stable VBR temperature coefficient (0.095%/°C). Its unidirectional configuration enables integration into DC power rails where reverse conduction must be blocked.
Thermal performance is characterized with a 5mm × 5mm copper pad test board: RθJL = 20°C/W and RθJA = 62°C/W ensure reliable operation under sustained surge conditions in compact automotive and industrial PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 22.4 V / 24.7 V - Breakdown occurs within this range at 1 mA test current, defining turn-on threshold tolerance |
| VC @ IPPM | 32.5 V - Clamped voltage during 12.3 A 10/1000μs surge, limiting downstream component stress |
| PPPM | 400 W - Peak pulse power handling capability per single transient event |
| TJ max | +175 °C - Enables use in under-hood automotive environments without derating |
| RθJL | 20 °C/W - Low thermal resistance from junction to lead supports high-power transient absorption |
| Polarity | Unidirectional - Blocks reverse current; suitable for DC supply rail protection only |
Pinout & Package
Package: Thin SMA - Surface-mount package with cathode band marking, UL 94V-0 rated molding compound, matte tin-plated leads, and 0.030g mass. Compliant with JESD201 Class 2 whisker testing and J-STD-020 moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side of protected DC rail; conducts during forward surge events |
| Cathode | Reverse-biased terminal | Marked by band; connected to higher-potential rail; avalanche conduction initiates when VWM exceeded |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock |
| Glass passivated junction | Enhances long-term stability and reduces parameter drift under thermal stress and humidity exposure |
| VBR tempco | 0.095%/°C - Predictable breakdown shift across -55°C to +175°C operating range |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive for environmentally constrained applications |
| Thin SMA footprint | Enables high-density placement on space-constrained PCBs while maintaining 400W surge capability |
Applications
| BLDC Motor Drive Protection | Battery Management System (BMS) |
|---|---|
Use Scenario: Suppresses inductive kickback spikes generated during MOSFET switching in 24V/48V BLDC motor controllers. IC Role / Device Role / Timing Role: Unidirectional TVS placed across motor phase terminals or DC bus to clamp transients before they reach gate drivers or MCU inputs. Use Value: Limits clamping voltage to 32.5V at 12.3A, preventing damage to 36V-rated gate drivers and enabling robust operation per ISO 7637-2 Pulse 1/2a. | Use Scenario: Protects cell monitoring ICs and communication interfaces in 12–48V lithium-ion battery packs against load dump and jump-start surges. IC Role / Device Role / Timing Role: Mounted at pack input terminals to absorb 400W pulses without degradation, preserving accuracy of voltage/current sensing circuits. Use Value: Maintains <1μA leakage at 20V VWM, avoiding parasitic discharge that would reduce BMS standby efficiency or cause false fault triggers. |
| Automotive Lighting Module | Switching Mode Power Supply (SMPS) |
Use Scenario: Shields LED driver ICs and CAN transceivers in headlamp control units from alternator-induced transients during ignition and load dump. IC Role / Device Role / Timing Role: Unidirectional TVS on 12V supply rail upstream of DC-DC converters and microcontrollers. Use Value: AEC-Q101 qualification ensures compliance with automotive environmental stress profiles, including 1000-hour HTOL at 175°C junction temperature. | Use Scenario: Safeguards primary-side controller ICs and secondary-side rectifiers in AC-DC adapters and industrial SMPS against line surges and cross-talk. IC Role / Device Role / Timing Role: Placed across bulk capacitor or output rail to limit transient overshoot during startup or short-circuit recovery. Use Value: 20°C/W junction-to-lead thermal resistance allows rapid heat transfer to PCB copper, sustaining repeated 400W pulses without thermal runaway. |
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 20V VWM, but 400W PPPM rating achieved at lower IPPM (12.3A vs. 12.5A); slightly higher VC (34.0V) | Identical unidirectional function; not AEC-Q101 qualified | Select SMAJ20A only for non-automotive industrial use where qualification is not required |
| SMBJ20A | Higher package thermal mass (SMB vs. Thin SMA); same VWM/VBR/VC specs; RθJL = 15°C/W | Requires larger PCB footprint; better steady-state power handling (10W vs. 7.5W PD) | Choose SMBJ20A when board layout permits larger package and higher continuous power margin is needed |
Compared with SMAJ20A and SMBJ20A, the SMA4F20AH uniquely combines AEC-Q101 qualification, Thin SMA footprint, and 20°C/W thermal resistance-making it optimal for space-constrained, thermally demanding automotive modules where qualification and reliability are mandatory.
Availability
SMA4F20AH is available at Aetrix Electronics and suitable for automotive BLDC motor drives, battery management systems, and lighting modules requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMA4F20AH 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 power devices, TVS diodes, and rectifiers for automotive and industrial markets.
The SMA4FxxAH series was developed specifically for AEC-Q101-compliant transient suppression in next-generation automotive electrification systems, emphasizing thermal robustness, low leakage, and consistent clamping performance across wide temperature ranges.
FAQ
What is the maximum clamping voltage of the SMA4F20AH under a 10/1000μs surge?
The SMA4F20AH has a maximum clamping voltage (VC) of 32.5 V when subjected to its rated peak pulse current of 12.3 A with a 10/1000μs waveform. This value is measured per JEDEC standards and guarantees predictable overvoltage limiting for downstream components such as gate drivers or microcontrollers in automotive applications.
Is the SMA4F20AH qualified for automotive use?
Yes, the SMA4F20AH is AEC-Q101 qualified, having passed stress tests including temperature cycling, high-temperature operating life, and mechanical shock. This qualification confirms its suitability for under-hood and cabin-mounted automotive electronics where reliability under harsh environmental conditions is mandatory.
What is the thermal resistance from junction to lead (RθJL) for the SMA4F20AH?
The SMA4F20AH has a typical junction-to-lead thermal resistance (RθJL) of 20°C/W when mounted on a 5mm × 5mm copper pad test board. This low value enables efficient heat transfer to the PCB, supporting repeated 400W transient absorption without exceeding the 175°C maximum junction temperature.
Does the SMA4F20AH have unidirectional or bidirectional polarity?
The SMA4F20AH is a unidirectional TVS diode, indicated by its single cathode band marking and specified forward voltage (VF = 3.5 V @ 25 A). It conducts only in reverse avalanche mode during overvoltage events and blocks current in the forward direction, making it appropriate for DC rail protection only.
What packaging option is available for the SMA4F20AH?
The SMA4F20AH is supplied in Thin SMA package format on tape-and-reel, with 14,000 units per reel. The package features matte tin-plated leads compliant with J-STD-002 solderability requirements and meets J-STD-020 moisture sensitivity level 1, eliminating bake requirements prior to reflow.
SMA4F20AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA4F
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.4V
- Voltage - Clamping (Max) @ Ipp:
- 32.5V
- Current - Peak Pulse (10/1000µs):
- 12.3A
- Power - Peak Pulse:
- 400W
- 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:
- Thin SMA
SMA4F20AH FAQ
1.How can I place an order for SMA4F20AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA4F20AH 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 SMA4F20AH reliable?
The price and inventory of SMA4F20AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA4F20AH is usually 5 days.
3.What payment methods are accepted for SMA4F20AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA4F20AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA4F20AH?
SMA4F20AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA4F20AH 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 SMA4F20AH?
For technical support, including SMA4F20AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA4F20AH requirements.
6.How does Aetrix verify that SMA4F20AH is sourced from the original manufacturer or authorized distributors?
All SMA4F20AH 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 SMA4F20AH meets industry standards.
7.What is the process for return or replacement of SMA4F20AH?
All SMA4F20AH units undergo pre-shipment inspection (PSI). If there is an issue with SMA4F20AH, 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 SMA4F20AH part is unused and in its original packaging.
Return procedure for SMA4F20AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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