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Taiwan Semiconductor Corporation SMA4F21AH MWG
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- Part No.:
- SMA4F21AH MWG
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA4F21AH MWG.pdf
- Description:
- 400W, 24.7V, 5%, UNIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:4,350
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMA4F21AH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with a 21V working stand-off voltage, 23.5–25.9V breakdown range at 1mA, and 34.1V clamping voltage at 11.7A peak pulse current; used for overvoltage protection in BLDC motor drives and automotive battery management systems.
For engineers reviewing the SMA4F21AH datasheet, SMA4F21AH pinout, SMA4F21AH application, or SMA4F21AH equivalent, key selection criteria include its AEC-Q101 qualification, 175°C max junction temperature, Thin SMA package thermal performance (RθJL = 20°C/W), and unidirectional polarity for DC rail protection.
Technical Context
This TVS diode employs a glass-passivated silicon junction optimized for fast response to transient surges (10/1000µs waveform), with low leakage (<1µA @ 21V) and stable VBR temperature coefficient (0.095%/°C). Its unidirectional configuration enables integration into DC power rails where reverse blocking is required.
Designed for high-reliability automotive and industrial environments, it meets JESD201 Class 2 whisker resistance, UL 94V-0 molding compound rating, and moisture sensitivity level 1 per J-STD-020 - enabling standard reflow assembly without dry-pack handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 21 V - Maximum continuous reverse operating voltage before conduction begins |
| VBR @ IT=1mA | 23.5–25.9 V - Verified breakdown threshold ensuring predictable clamping onset |
| VC @ IPPM=11.7A | 34.1 V - Clamped voltage during 400W 10/1000µs surge, limiting downstream stress |
| PPPM | 400 W - Peak pulse power handling capability under standardized surge conditions |
| TJ max | 175 °C - Enables operation in under-hood automotive and high-ambient industrial locations |
| RθJL | 20 °C/W - Low junction-to-lead thermal resistance supports reliable power dissipation on PCB |
| Polarity | Unidirectional - Provides reverse-biased blocking for DC supply line protection |
Pinout & Package
Package: Thin SMA - Surface-mount package with cathode band marking, matte tin-plated leads, 0.030g mass, and UL 94V-0 rated epoxy body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side of protected DC rail (e.g., ground or return path) |
| Cathode | Reverse-blocking / clamping terminal | Connected to higher-potential side (e.g., +21V rail); marked by band; conducts during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| Glass-passivated junction | Enhances long-term stability and reduces parameter drift under thermal stress |
| VBR tempco ≤ 0.095%/°C | Minimizes variation in clamping threshold across -55°C to +175°C operating range |
| Moisture sensitivity level 1 | Eliminates bake requirements prior to reflow, reducing manufacturing complexity |
| Halogen-free per IEC 61249-2-21 | Complies with environmental regulations for RoHS-compliant end products |
Applications
| BLDC Motor Drive Protection | Automotive Battery Management |
|---|---|
Use Scenario: Suppresses inductive kickback and load dump transients in 24V BLDC gate driver power rails. IC Role / Device Role / Timing Role: Unidirectional TVS placed across DC bus to clamp spikes before they reach MOSFET drivers or MCU power inputs. Use Value: Limits voltage to ≤34.1V during 400W surges, preventing damage to 36V-rated gate drivers and maintaining system uptime. | Use Scenario: Protects BMS analog front-end and cell monitoring ICs from jump-start and alternator load-dump events. IC Role / Device Role / Timing Role: Standoff-rated TVS on 21V auxiliary supply rail, absorbing 10/1000µs transients up to 11.7A. Use Value: Maintains signal integrity for precision voltage/current sensing by holding rail voltage within safe operating area during 12V system surges. |
| LED Driver Power Input | Industrial SMPS Output Rail |
Use Scenario: Shields constant-current LED driver ICs from input voltage overshoot during hot-plug or capacitor discharge events. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 21V input stage, activated within nanoseconds of transient onset. Use Value: Prevents latch-up or permanent damage to driver ICs rated for ≤30V absolute maximum, leveraging 34.1V clamping ceiling. | Use Scenario: Safeguards secondary-side synchronous rectifiers and feedback optocouplers in 21V-output isolated DC/DC converters. IC Role / Device Role / Timing Role: Fast-response TVS on regulated output rail to absorb reflected switching noise and cross-regulation spikes. Use Value: Ensures stable regulation by limiting output excursions to <35V, avoiding false triggering of OVP circuits or output capacitor overstress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ21A | 400W rating, same VWM/VC, but RθJA = 65°C/W vs. 62°C/W; no AEC-Q101 qualification | Not approved for automotive use; suitable for industrial SMPS only | Select when AEC-Q101 is not required and cost sensitivity outweighs automotive compliance |
| SMBJ21A | Same electrical specs, but SMB package (higher RθJA = 70°C/W, larger footprint) | Lower power density; requires more PCB area and reduced surge margin at elevated ambient | Choose only if existing layout uses SMB pads and thermal derating is acceptable |
Compared with SMAJ21A and SMBJ21A, the SMA4F21AH delivers identical clamping performance with superior thermal efficiency (RθJL = 20°C/W) and mandatory AEC-Q101 validation - making it the preferred choice for space-constrained, thermally demanding automotive and BLDC applications.
Availability
SMA4F21AH is available at Aetrix Electronics and suitable for BLDC motor drives, automotive battery management systems, LED driver inputs, and industrial SMPS requiring stable component supply with AEC-Q101 assurance and tight thermal design margins.
Supply support for SMA4F21AH 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 with global distribution and automotive qualification capabilities.
The SMA4FxxAH series was developed specifically for AEC-Q101-compliant transient suppression in compact, high-temperature automotive and industrial power systems using the Thin SMA footprint.
FAQ
What is the clamping voltage of the SMA4F21AH under full-rated surge conditions?
The SMA4F21AH exhibits a maximum clamping voltage (VC) of 34.1 V when subjected to its rated 400W peak pulse power with a 10/1000µs waveform, corresponding to a peak pulse current of 11.7 A. This value is measured at TA = 25°C and ensures downstream circuitry remains within safe operating limits during transient events. The SMA4F21AH maintains this clamping performance across its specified junction temperature range.
Is the SMA4F21AH suitable for automotive applications?
Yes, the SMA4F21AH is AEC-Q101 qualified and designed for automotive use, including battery management systems and BLDC motor control modules. It meets stringent reliability requirements such as temperature cycling, highly accelerated life testing, and mechanical robustness per JESD201 Class 2. Its 175°C maximum junction temperature and moisture sensitivity level 1 rating further support under-hood deployment without special handling.
What does the marking code "4F021" indicate on the SMA4F21AH device?
The marking code "4F021" laser-etched on the SMA4F21AH case identifies the specific variant within the SMA4FxxAH family, confirming its 21V working stand-off voltage rating. This code is standardized across Taiwan Semiconductor's packaging and matches the part number designation in ordering documentation and electrical specifications tables. It is distinct from other variants like "4F024" (SMA4F24AH) or "4F030" (SMA4F30AH).
How does the Thin SMA package of the SMA4F21AH improve thermal performance compared to standard SMA?
The Thin SMA package of the SMA4F21AH achieves a junction-to-lead thermal resistance (RθJL) of 20°C/W - lower than standard SMA variants - due to optimized leadframe geometry and die attach. This enables more efficient heat transfer from the silicon junction to the PCB copper pad, supporting sustained 400W surge handling in compact layouts. Its 0.030g mass and UL 94V-0 molding compound also enhance manufacturability and safety.
Can the SMA4F21AH be used in bidirectional configurations?
No, the SMA4F21AH is a unidirectional TVS diode and must be used with correct polarity: cathode connected to the protected positive rail and anode to ground or return. It does not provide symmetrical clamping for AC or bipolar transients. For bidirectional protection, a dedicated bidirectional TVS (e.g., SMA4F21AY) or back-to-back unidirectional devices would be required - the SMA4F21AH itself is not rated or characterized for reverse conduction.
SMA4F21AH MWG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 21V
- Voltage - Breakdown (Min):
- 23.5V
- Voltage - Clamping (Max) @ Ipp:
- 34.1V
- Current - Peak Pulse (10/1000µs):
- 11.7A
- 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
SMA4F21AH MWG FAQ
1.How can I place an order for SMA4F21AH MWG through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA4F21AH MWG 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 SMA4F21AH MWG reliable?
The price and inventory of SMA4F21AH MWG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA4F21AH MWG is usually 5 days.
3.What payment methods are accepted for SMA4F21AH MWG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA4F21AH MWG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA4F21AH MWG?
SMA4F21AH MWG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA4F21AH MWG 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 SMA4F21AH MWG?
For technical support, including SMA4F21AH MWG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA4F21AH MWG requirements.
6.How does Aetrix verify that SMA4F21AH MWG is sourced from the original manufacturer or authorized distributors?
All SMA4F21AH MWG 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 SMA4F21AH MWG meets industry standards.
7.What is the process for return or replacement of SMA4F21AH MWG?
All SMA4F21AH MWG units undergo pre-shipment inspection (PSI). If there is an issue with SMA4F21AH MWG, 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 SMA4F21AH MWG part is unused and in its original packaging.
Return procedure for SMA4F21AH MWG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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