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STMicroelectronics SMA4F188A
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- Part No.:
- SMA4F188A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA4F188A.pdf
- Description:
- TVS DIODE 188VWM 328VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:9,242
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Product details
Overview
SMA4F188A from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-reliability surge protection in power rails and signal lines. It features a 188 V stand-off voltage (VRM), 328 V clamping voltage at 1 A (VCL), 400 W peak pulse power (10/1000 µs), and operates up to 175 °C junction temperature - deployed in industrial power supplies and telecom DC input stages.
For engineers reviewing the SMA4F188A datasheet, SMA4F188A pinout, SMA4F188A application, or SMA4F188A equivalent, key selection criteria include clamping performance at 1 A, leakage current stability across temperature (0.2 µA @ 25 °C, 1 µA @ 85 °C), dynamic resistance (26.2 Ω), and IEC 61000-4-2 level 4 ESD robustness (±25 kV contact / ±30 kV air).
Technical Context
The SMA4F188A uses planar silicon avalanche technology to deliver precise breakdown behavior with low leakage and stable thermal response. Its unidirectional configuration supports DC-biased protection paths, and its αT voltage temperature coefficient of 10.8 × 10⁻⁴ /°C enables predictable VBR and VCL drift over temperature.
Designed for high-junction-temperature operation (Tj max = 175 °C), it maintains 200 W pulse capability at Tj = 175 °C per Figure 3. The device complies with IEC 61000-4-2 (150 pF / 330 Ω), UL94 V0, and J-STD-020 MSL Level 1 - confirming suitability for reflow-soldered industrial PCBs without moisture sensitivity concerns.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 188 V - maximum continuous reverse operating voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 209–231 V @ 1 mA - defines onset of avalanche conduction under controlled test conditions |
| Clamping Voltage (VCL) | 328 V @ 1 A (10/1000 µs) - limits transient voltage seen by downstream circuitry during surge events |
| Peak Pulse Power | 400 W (10/1000 µs), 2.5 kW (8/20 µs) - determines survivability against standardized lightning/surge waveforms |
| Leakage Current | 0.2 µA @ 25 °C, 1 µA @ 85 °C - ensures minimal standby power loss and signal integrity in high-impedance nodes |
| Dynamic Resistance (RD) | 26.2 Ω - governs VCL rise vs. IPP; lower RD improves clamping linearity under high-current transients |
| Junction Temperature Range | −55 to +175 °C - supports operation in enclosed industrial enclosures and automotive under-hood environments |
Pinout & Package
The SMA4F188A is housed in an industry-standard SMA (DO-214AC) flat package with two terminals: cathode and anode. The package conforms to JEDEC registered outline and IPC7531 footprint guidelines, enabling drop-in compatibility with existing TVS layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction; connected to protected line's lower-potential side | Enables unidirectional clamping - only conducts when protected line goes negative relative to reference ground |
| Cathode | Current exit point during reverse avalanche; tied to system ground or common reference | Defines polarity-sensitive protection path - must be routed to lowest-impedance ground plane for effective surge shunting |
Key Features
| Feature | Design Value |
|---|---|
| High-Temperature Reliability | Rated for continuous operation up to 175 °C junction temperature - eliminates derating concerns in thermally constrained designs |
| Low-Leakage Planar Construction | 0.2 µA IR max @ VRM and 25 °C - preserves signal integrity in high-impedance sensor interfaces and precision analog front-ends |
| IEC 61000-4-2 Level 4 Compliance | Withstands ±25 kV contact and ±30 kV air discharge - meets stringent EMC requirements for industrial and telecom equipment |
| Matte Tin Lead Finish | RoHS-compliant, whisker-resistant plating per JESD-201 Class 2 - ensures long-term solder joint reliability in automated assembly |
Applications
| Industrial Power Supply Input Protection | Telecom DC Feeder Line Protection |
|---|---|
Use Scenario: 48 V DC telecom power feeders exposed to induced surges from nearby lightning strikes or switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between DC+ and chassis ground to clamp positive-going transients above 188 V. Use Value: Limits transient voltage to ≤328 V at 1 A, protecting upstream rectifiers and downstream DC-DC converters from overvoltage failure. | Use Scenario: AC/DC power supply inputs in factory automation controllers subjected to load dump and inductive kickback. IC Role / Device Role / Timing Role: Standoff-rated TVS on primary-side DC bus to absorb repetitive 400 W surges without degradation. Use Value: Maintains 200 W pulse capability even at 175 °C junction temperature - ensures long-term reliability in sealed enclosures. |
| Automotive Body Control Module (BCM) Power Rail | Smart Meter AC/DC Auxiliary Supply |
Use Scenario: 12 V battery-supplied BCM modules encountering ISO 7637-2 pulse 1 and pulse 2a transients. IC Role / Device Role / Timing Role: Secondary-level TVS on regulated 5 V/3.3 V rails to suppress coupled transients after primary filtering. Use Value: Low 1 µA leakage at 85 °C prevents excessive quiescent current drain in always-on monitoring circuits. | Use Scenario: Auxiliary power derived from mains via bridge rectifier in smart electricity meters, subject to fast-rising surges. IC Role / Device Role / Timing Role: Unidirectional clamping device on rectified DC output to protect metering ICs and RTC backup circuits. Use Value: Dynamic resistance of 26.2 Ω ensures predictable clamping rise time and minimal overshoot during 8/20 µs surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ188A (Littelfuse) | Same VRM (188 V), but higher VCL (350 V @ 1 A) and lower PPP (400 W same, but derates faster above 25 °C) | Limited to ambient-temperature-limited deployments; not rated for 175 °C continuous operation | Select when cost sensitivity outweighs high-temperature reliability needs |
| 1.5SMC188A (ON Semiconductor) | Higher package thermal mass (SMC), 350 V VCL @ 1 A, 1.5 kW 8/20 µs rating, but 150 °C Tj max | Better surge energy handling, but unsuitable for >150 °C board hotspots or sealed enclosures | Select when peak surge energy exceeds 400 W and board layout allows larger SMC footprint |
Compared with SMAJ188A and 1.5SMC188A, the SMA4F188A uniquely combines 175 °C junction rating, ultra-low leakage, and tight VCL (328 V) - making it optimal for thermally aggressive, low-power-consumption industrial and telecom applications where long-term parametric stability is critical.
Availability
SMA4F188A is available at Aetrix Electronics and suitable for industrial power supply input protection, telecom DC feeder line protection, automotive body control module (BCM) power rail hardening, and smart meter auxiliary supply surge suppression requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SMA4F188A 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, power, and sensing technologies with over 40 years of analog and protection device innovation.
The SMA4F Transil series targets high-reliability transient suppression in thermally demanding environments, emphasizing low leakage, stable high-temperature performance, and compliance with IEC/UL/IPC standards for industrial-grade PCB assembly.
FAQ
What is the maximum clamping voltage of SMA4F188A under a 10/1000 µs surge?
The maximum clamping voltage (VCL) of SMA4F188A is 328 V at 1 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature due to its 10.8 × 10⁻⁴ /°C voltage temperature coefficient - at 175 °C, VCL rises approximately 16.5% above the 25 °C value.
Does SMA4F188A support lead-free reflow soldering?
Yes - SMA4F188A features matte tin lead finish compliant with RoHS and JESD-201 Class 2 whisker testing. Its recommended reflow profile follows IPC/JEDEC J-STD-020, with peak temperature of 240–245 °C for ≤60 seconds, and it is rated MSL Level 1 (unlimited floor life).
How does the dynamic resistance affect real-world clamping performance?
With a measured dynamic resistance (RD) of 26.2 Ω, SMA4F188A exhibits linear VCL increase proportional to applied peak pulse current (IPP). For example, at 5 A surge, VCL ≈ 328 V + (26.2 Ω × 4 A) = ~433 V - enabling accurate system-level overvoltage margining during surge design.
Can SMA4F188A be used in bidirectional protection configurations?
No - SMA4F188A is strictly unidirectional (Type A), with cathode marked and designed for DC-biased applications. Bidirectional protection requires pairing two devices or selecting a dedicated bidirectional variant like SMA4F188CA; using this part in reverse-biased mode risks permanent breakdown below −188 V.
SMA4F188A 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):
- 188V (Max)
- Voltage - Breakdown (Min):
- 209V
- Voltage - Clamping (Max) @ Ipp:
- 328V
- Current - Peak Pulse (10/1000µs):
- 1.4A
- 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
SMA4F188A FAQ
1.How can I place an order for SMA4F188A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA4F188A 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 SMA4F188A reliable?
The price and inventory of SMA4F188A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA4F188A is usually 5 days.
3.What payment methods are accepted for SMA4F188A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA4F188A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA4F188A?
SMA4F188A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA4F188A 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 SMA4F188A?
For technical support, including SMA4F188A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA4F188A requirements.
6.How does Aetrix verify that SMA4F188A is sourced from the original manufacturer or authorized distributors?
All SMA4F188A 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 SMA4F188A meets industry standards.
7.What is the process for return or replacement of SMA4F188A?
All SMA4F188A units undergo pre-shipment inspection (PSI). If there is an issue with SMA4F188A, 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 SMA4F188A part is unused and in its original packaging.
Return procedure for SMA4F188A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMA4F188A Tags
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