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STMicroelectronics SMM4F20A-TR
- Part No.:
- SMM4F20A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-222AA
- Datasheet:
-
SMM4F20A-TR.pdf
- Description:
- TVS DIODE 20VWM 42.8VC DO222-AA
- Quantity:
- Payment:
- Shipping:
Inventory:9,836
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Product details
Overview
SMM4F20A-TR from STMicroelectronics is a unidirectional 400 W transient voltage suppression (TVS) diode designed for robust ESD and surge protection in power rails and I/O lines. It features a standoff voltage of 20 V, clamping voltage of 32.4 V at 12 A (10/1000 µs), leakage current ≤0.2 µA at 25 °C, and operates up to 175 °C junction temperature - ideal for automotive body electronics and industrial sensor interfaces.
For engineers reviewing the SMM4F20A-TR datasheet, SMM4F20A-TR pinout, SMM4F20A-TR application, or SMM4F20A-TR equivalent, key selection criteria include its 32.4 V clamping performance at 12 A, flat STmite Flat package (0.85 mm height), unidirectional polarity, low leakage, and IEC 61000-4-2 level 4 compliance (±30 kV contact/air discharge).
Technical Context
This TVS diode uses planar silicon technology to achieve stable high-temperature operation (Tj up to 175 °C) and low leakage (<0.2 µA at 25 °C). Its unidirectional configuration provides asymmetric clamping optimized for DC-biased lines such as 24 V supply rails and CAN transceiver I/Os.
The device delivers 400 W peak pulse power (10/1000 µs) and 2.5 kW (8/20 µs), with dynamic resistance of 0.600 Ω at 12 A (10/1000 µs) and 0.250 Ω at 70 A (8/20 µs), enabling precise overvoltage limiting under fast transients per IEC 61000-4-4 (4 kV) and IEC 61000-4-2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRWM) | 20 V - Maximum continuous reverse operating voltage before clamping begins |
| Breakdown Voltage (VBR) | 22.8–25.2 V at 1 mA - Ensures reliable triggering margin above nominal rail |
| Clamping Voltage (VCL) | 32.4 V at 12 A (10/1000 µs) - Limits downstream voltage during surge events |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - Sustains standard lightning-surge energy without failure |
| Leakage Current (IR) | ≤0.2 µA at 25 °C - Minimizes standby power loss in battery-powered systems |
| Junction Temperature Range | −55 to +175 °C - Supports under-hood automotive and industrial ambient conditions |
| ESD Rating | ±30 kV (IEC 61000-4-2, contact/air) - Exceeds Level 4 immunity requirement |
Pinout & Package
The SMM4F20A-TR uses the STmite Flat surface-mount package (JEDEC MO-275 compatible), measuring 1.90 mm × 3.80 mm × 0.85 mm (L × W × H), with matte tin-plated leads and MSL level 1 moisture sensitivity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node in unidirectional clamp configuration |
| Cathode | High-side surge input terminal | Placed on protected line (e.g., 24 V rail or signal trace); marked with cathode bar |
Key Features
| Feature | Design Value |
|---|---|
| Flat STmite Flat package | 0.85 mm profile enables use in space-constrained PCB layouts and automated assembly |
| High-temperature reliability | Rated for 175 °C Tj with 160 W surge capability at max temperature - ensures long-term stability in hot environments |
| Low dynamic resistance | 0.600 Ω (10/1000 µs) - reduces clamping overshoot and improves protection precision |
| IEC 61000-4-2 Level 4 compliance | ±30 kV contact/air discharge - eliminates need for external ESD staging in end-equipment certification |
| UL94 V0 flammability rating | Self-extinguishing epoxy molding compound - meets safety requirements for industrial and automotive enclosures |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Module |
|---|---|
Use Scenario: Protecting 24 V supply inputs against load dump and ISO 7637-2 pulses in BCM ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between fused 24 V rail and local regulator input. Use Value: Clamps transients to ≤32.4 V, preventing LDO overvoltage failure while maintaining <0.2 µA leakage at ambient temperature. | Use Scenario: Safeguarding 24 V digital input channels from field-wiring induced surges in factory automation PLCs. IC Role / Device Role / Timing Role: Primary surge suppressor on each optocoupler input path, upstream of series resistor. Use Value: Withstands repeated 4 kV IEC 61000-4-4 bursts and ±30 kV ESD without degradation, ensuring >10-year field reliability. |
| Smart Sensor Node (RS-485 Interface) | Medical Infusion Pump Power Rail |
Use Scenario: Protecting RS-485 transceiver VCC and bus lines in harsh industrial networks. IC Role / Device Role / Timing Role: Local TVS on 3.3 V/5 V bias rail and differential bus lines (A/B), configured unidirectionally. Use Value: Low 0.2 µA leakage avoids signal integrity issues; 175 °C rating supports sealed enclosure thermal profiles. | Use Scenario: Securing 24 V main power input of battery-backed infusion pumps against hospital-grade ESD events. IC Role / Device Role / Timing Role: First-line transient suppressor before DC-DC converter input stage. Use Value: UL94 V0 and J-STD-020 MSL level 1 ensure compliance with IEC 60601-1 safety and reflow process requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20A | Higher clamping voltage (34.0 V @ 11.1 A), SMA package (2.5 mm height), lower surge rating (400 W same, but derates faster above 25 °C) | Less suitable for ultra-low-profile designs; requires more board area and higher thermal impedance | Choose when legacy SMA footprint compatibility is required and height constraint is relaxed |
| 1.5SMC20A | Same 20 V standoff, but larger SMC package (7.1 mm × 6.2 mm), 1.5 kW peak power (8/20 µs), higher leakage (1.0 µA) | Better for high-energy surges where board space allows; not suitable for dense automotive modules | Prefer for industrial AC-input front-end protection where size is secondary to energy handling |
Compared with SMAJ20A and 1.5SMC20A, the SMM4F20A-TR offers superior height efficiency (0.85 mm vs ≥2.5 mm), tighter clamping (32.4 V vs 34.0 V/36.0 V), and lower leakage - making it optimal for next-gen compact, high-reliability 24 V systems.
Availability
SMM4F20A-TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC input protection, smart sensor interface design, and medical device power rail hardening requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMM4F20A-TR 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 management solutions with broad IP and manufacturing scale.
The SMM4F series belongs to ST's high-reliability TVS portfolio, engineered specifically for space-constrained, high-temperature applications demanding low leakage, precise clamping, and full IEC/UL compliance - especially in automotive and industrial control systems.
FAQ
What is the maximum clamping voltage of SMM4F20A-TR under a 10/1000 µs surge?
The maximum clamping voltage is 32.4 V at 12 A for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature per the αT coefficient (9.4 × 10−4/°C), reaching ~35.1 V at Tj = 125 °C using the formula VCL(Tj) = VCL(25 °C) × [1 + αT × (Tj − 25)].
Is SMM4F20A-TR suitable for bidirectional signal line protection?
No - SMM4F20A-TR is unidirectional and intended for DC-biased lines like 24 V power rails or single-ended I/Os. For bidirectional protection (e.g., USB, RS-485, or AC-coupled signals), ST recommends the bidirectional SMM4F20CA variant, which has symmetric clamping and identical package/mechanical specs.
Does SMM4F20A-TR require derating at elevated ambient temperatures?
Yes - peak pulse power must be derated above 25 °C ambient. At Tamb = 85 °C, the 10/1000 µs rating drops to ~280 W (per Figure 3 in DS5630), and at 125 °C, it falls to ~180 W. Derating curves are provided in the datasheet to ensure safe operation within thermal limits.
Can SMM4F20A-TR be used in lead-free reflow processes?
Yes - it is qualified for lead-free soldering per J-STD-020 MSL level 1, with a maximum peak reflow temperature of 245 °C (240–245 °C typical) and ramp rates specified in Figure 20 of DS5630. The matte tin plating ensures compatibility with standard SnAgCu profiles and eliminates whisker risk (JESD201 Class 2).
SMM4F20A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-222AA
- Series:
- SMM4F, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.8V
- Voltage - Clamping (Max) @ Ipp:
- 42.8V
- Current - Peak Pulse (10/1000µs):
- 54A (8/20µs)
- 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:
- STmite Flat (DO222-AA)
SMM4F20A-TR FAQ
1.How can I place an order for SMM4F20A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMM4F20A-TR 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 SMM4F20A-TR reliable?
The price and inventory of SMM4F20A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMM4F20A-TR is usually 5 days.
3.What payment methods are accepted for SMM4F20A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMM4F20A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMM4F20A-TR?
SMM4F20A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMM4F20A-TR 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 SMM4F20A-TR?
For technical support, including SMM4F20A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMM4F20A-TR requirements.
6.How does Aetrix verify that SMM4F20A-TR is sourced from the original manufacturer or authorized distributors?
All SMM4F20A-TR 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 SMM4F20A-TR meets industry standards.
7.What is the process for return or replacement of SMM4F20A-TR?
All SMM4F20A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMM4F20A-TR, 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 SMM4F20A-TR part is unused and in its original packaging.
Return procedure for SMM4F20A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMM4F20A-TR Tags
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ESD9B5.0ST5G
onsemi
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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