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STMicroelectronics SMA4F14A
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- Part No.:
- SMA4F14A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA4F14A.pdf
- Description:
- TVS DIODE 14VWM 29VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:670
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Product details
Overview
SMA4F14A from STMicroelectronics is a unidirectional 400 W transient voltage suppression (TVS) diode designed for primary-level surge protection in DC power rails and signal lines. It features a 14 V stand-off voltage (VRM), 15.7–17.3 V breakdown voltage (VBR) at 1 mA, 23.1 V clamping voltage (VCL) at 17.2 A (10/1000 µs), and operates up to +175 °C junction temperature - enabling robust protection in automotive body electronics, industrial PLC I/O modules, and telecom power interfaces.
For engineers reviewing the SMA4F14A datasheet, SMA4F14A pinout, SMA4F14A application, or SMA4F14A equivalent, key selection criteria include clamping performance under 10/1000 µs surges, low leakage (<0.2 µA @ 25 °C), high-temperature reliability, and compatibility with IPC7531-compliant SMA flat footprint layouts.
Technical Context
The SMA4F14A employs planar silicon avalanche technology to deliver precise, repeatable clamping response during IEC 61000-4-2 ESD events (±25 kV contact / ±30 kV air) and IEC 61000-4-5 surge transients. Its unidirectional configuration supports DC-biased lines where reverse polarity is not expected.
Thermal design is enabled by a 175 °C maximum junction temperature rating and validated thermal impedance curves showing <100 °C/W junction-to-ambient under single-pulse conditions on FR4 with recommended copper area. Dynamic resistance is specified at 0.337 Ω, directly supporting VCL calculation via VCL = VBR + RD × IPP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 14 V - Maximum continuous reverse operating voltage before leakage exceeds 0.2 µA; defines safe DC bias margin. |
| Breakdown Voltage (VBR) | 15.7–17.3 V at 1 mA - Avalanche onset range; ensures predictable turn-on during overvoltage events. |
| Clamping Voltage (VCL) | 23.1 V at 17.2 A (10/1000 µs) - Peak voltage seen by protected circuit during standardized surge; limits stress on downstream ICs. |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - Sustained energy-handling capability at 25 °C ambient; derates to 200 W at 175 °C Tj. |
| Leakage Current (IRM) | 0.2 µA at 25 °C, 1 µA at 85 °C - Ultra-low reverse leakage preserves battery life and signal integrity in always-on systems. |
| Junction Temperature Range | −55 to +175 °C - Enables deployment in under-hood automotive, industrial motor drives, and outdoor telecom equipment. |
| ESD Withstand | ±25 kV contact / ±30 kV air (IEC 61000-4-2 Level 4) - Exceeds automotive and industrial immunity requirements without external shielding. |
Pinout & Package
The SMA4F14A is housed in an industry-standard SMA (DO-214AC) flat package with matte tin-plated leads, compliant with IPC7531 footprint and JEDEC MO-136AA outline. Dimensions: 4.60 mm × 2.90 mm × 2.25 mm (L × W × H), weight 39 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink node | Connected to protected line; conducts avalanche current to ground during overvoltage. |
| Anode | Reference / return path | Typically tied to system ground or low-impedance return; completes clamping loop during transient. |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature operation | Rated for continuous use up to +175 °C junction temperature - eliminates derating concerns in sealed enclosures or high-power density designs. |
| Low dynamic resistance | 0.337 Ω - Minimizes VCL rise under high-current surges, improving protection margin for 3.3 V/5 V logic and microcontrollers. |
| ESD-robust construction | Passes IEC 61000-4-2 Level 4 (±30 kV air) - reduces need for secondary ESD components in USB, RS-485, and CAN bus front-ends. |
| Planar junction technology | Enables tight VBR tolerance and stable leakage across temperature - critical for precision sensor supply rail protection. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Module |
|---|---|
Use Scenario: Protecting 12 V supply rail and LIN bus lines against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary TVS clamp on power input and communication lines; responds within nanoseconds to suppress >100 V transients. Use Value: Prevents latch-up or permanent damage to MCU I/O pins and transceiver ICs during vehicle battery disconnection/reconnection events. |
Use Scenario: Safeguarding 24 V DC digital input channels against field-wiring induced surges and inductive kickback. IC Role / Device Role / Timing Role: Front-end transient suppressor placed before optocoupler or Schmitt trigger input stage. Use Value: Maintains functional safety integrity by limiting input voltage to ≤23.1 V during 1 kV/500 A surge tests per IEC 61000-4-5. |
| Telecom Power Supply Input | Smart Meter AC/DC Auxiliary Rail |
Use Scenario: Clamping induced surges on 48 V telecom rectifier outputs exposed to lightning-induced coupling. IC Role / Device Role / Timing Role: Unidirectional TVS on secondary-side DC bus; coordinates with upstream MOVs and fuses. Use Value: Delivers 400 W peak pulse handling at 25 °C and retains 200 W capability at full 175 °C junction temperature - ensuring reliability in hot chassis environments. |
Use Scenario: Protecting isolated 5 V auxiliary supply derived from mains-connected SMPS in utility meters. IC Role / Device Role / Timing Role: Secondary-side TVS on post-regulator rail feeding metrology IC and RTC. Use Value: Ultra-low 0.2 µA leakage at 25 °C minimizes standby current drain, supporting 10-year battery-backed operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ14A (Bourns) | Same SMA package, 400 W rating, but higher VBR (15.6–17.2 V) and VCL (23.2 V @ 17.3 A); 1 µA leakage @ 85 °C vs. 1 µA for SMA4F14A. | Identical IEC 61000-4-2/4-5 compliance; slightly tighter VBR distribution aids margin analysis in high-volume production. | Select when tighter VBR binning or Bourns' long-term supply assurance is prioritized over ST's extended Tj rating. |
| SMBJ14A (Littelfuse) | SMB package (larger footprint), same 400 W rating, VBR 15.6–17.2 V, VCL 23.2 V @ 17.3 A, but max Tj = 150 °C (vs. 175 °C). | Requires PCB redesign due to SMB outline; lower thermal limit restricts use in high-ambient industrial enclosures. | Choose only if existing SMB layout prohibits SMA adoption and thermal derating to 150 °C is acceptable. |
Compared with SMAJ14A and SMBJ14A, the SMA4F14A offers superior high-temperature resilience (175 °C Tj), identical clamping performance, and optimized leakage for battery-sensitive applications - making it preferred for automotive and thermally constrained industrial deployments.
Availability
SMA4F14A is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O protection, and telecom power supply input stages requiring stable component supply across multi-year production cycles.
Supply support for SMA4F14A 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power discrete solutions with vertical manufacturing capabilities.
The SMA4F series belongs to ST's Transil™ TVS portfolio, engineered specifically for high-reliability transient suppression in harsh-environment applications where low leakage, high-temperature stability, and repeatable clamping are non-negotiable.
FAQ
What is the maximum clamping voltage of SMA4F14A under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 23.1 V at 17.2 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature per the αT coefficient (8.6 × 10⁻⁴/°C), reaching ~25.2 V at 175 °C Tj using the formula VCL(Tj) = VCL(25°C) × [1 + αT × (Tj − 25)].
Can SMA4F14A be used in bidirectional signal line protection?
No - SMA4F14A is strictly unidirectional and must be installed with cathode toward the protected line. For bidirectional protection (e.g., RS-485, USB D+/D−), ST recommends the SMA4F14CA variant or discrete back-to-back diode configurations; using SMA4F14A on AC-coupled lines risks forward conduction and failure.
How does the 175 °C junction rating impact board-level thermal design?
The 175 °C rating allows sustained operation in ambient temperatures up to 125 °C when mounted on FR4 with ≥1 cm² copper per lead, per ST's thermal resistance curves. It eliminates mandatory heatsinking in most automotive and industrial applications, reducing BOM cost and PCB area versus 150 °C-rated alternatives.
Is the SMA4F14A RoHS and REACH compliant?
Yes - SMA4F14A carries ST's ECOPACK®2 qualification, meeting RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. It uses matte tin plating and halogen-free molding compound, with full material declarations available in ST's ECOPACK® database.
SMA4F14A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA4F, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 14V
- Voltage - Breakdown (Min):
- 15.7V
- Voltage - Clamping (Max) @ Ipp:
- 29V
- Current - Peak Pulse (10/1000µs):
- 17.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMAflat
SMA4F14A FAQ
1.How can I place an order for SMA4F14A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA4F14A 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 SMA4F14A reliable?
The price and inventory of SMA4F14A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA4F14A is usually 5 days.
3.What payment methods are accepted for SMA4F14A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA4F14A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA4F14A?
SMA4F14A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA4F14A 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 SMA4F14A?
For technical support, including SMA4F14A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA4F14A requirements.
6.How does Aetrix verify that SMA4F14A is sourced from the original manufacturer or authorized distributors?
All SMA4F14A 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 SMA4F14A meets industry standards.
7.What is the process for return or replacement of SMA4F14A?
All SMA4F14A units undergo pre-shipment inspection (PSI). If there is an issue with SMA4F14A, 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 SMA4F14A part is unused and in its original packaging.
Return procedure for SMA4F14A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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