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STMicroelectronics SMM4F28A-TR
- Part No.:
- SMM4F28A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-216AA
- Datasheet:
-
SMM4F28A-TR.pdf
- Description:
- TVS DIODE 28VWM 59VC DO216AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,876
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Product details
Overview
SMM4F28A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for robust ESD and surge protection in high-reliability DC power rails and signal lines. It delivers 400 W peak pulse power (10/1000 µs), clamps transients to 45.4 V at 8 A, and operates up to 175 °C junction temperature - enabling use in automotive body control modules, industrial PLC I/O terminals, and 24 V telecom power interfaces.
For engineers reviewing the SMM4F28A-TR datasheet, SMM4F28A-TR pinout, SMM4F28A-TR application, or SMM4F28A-TR equivalent, key selection criteria include its 28 V standoff voltage, low 0.2 µA leakage at 25 °C, flat STmite Flat package (0.85 mm height), IEC 61000-4-2 level 4 compliance (±30 kV), and verified 53 Ω dynamic resistance at 8/20 µs surge.
Technical Context
The SMM4F28A-TR employs planar silicon junction technology optimized for low leakage and high thermal stability, supporting continuous operation at Tj = 175 °C without derating. Its unidirectional configuration provides asymmetric clamping with cathode-anode polarity, requiring correct orientation in series with protected lines.
It meets IEC 61000-4-2 (±30 kV contact/air) and IEC 61000-4-4 (4 kV) immunity standards, with clamping voltage defined by VCL = VBR(max) + RD × IPP. The 0.85 mm profile and STmite Flat outline (JEDEC-compliant) enable placement on dense PCBs where height clearance is constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRWM) | 28 V - Maximum continuous reverse working voltage before breakdown; sets operating margin for 24 V nominal systems. |
| Breakdown Voltage (VBR) | 31.4–34.7 V at 1 mA - Confirmed minimum/maximum threshold for avalanche conduction under transient stress. |
| Clamping Voltage (VCL) | 45.4 V at 8 A (10/1000 µs) - Peak voltage seen by downstream circuit during worst-case surge; defines protection window. |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - Sustained energy-handling capability at ambient; derates to 160 W at Tj = 175 °C. |
| Leakage Current (IR) | 0.2 µA at 25 °C, 1 µA at 85 °C - Ensures minimal loading on low-power sensor or battery-backed circuits. |
| Dynamic Resistance (RD) | 1.34 Ω (10/1000 µs), 0.458 Ω (8/20 µs) - Governs VCL rise slope; lower value improves clamping linearity under fast transients. |
| Junction Temperature Range | −55 °C to +175 °C - Enables deployment in under-hood automotive, industrial motor drives, and outdoor power supplies. |
Pinout & Package
STmite Flat surface-mount package: 2-terminal device in ultra-thin profile (0.85 mm max height), JEDEC-compliant outline (D = 1.90 mm, E = 3.80 mm), matte tin lead finish, MSL Level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to system ground or return path; must be routed with low-inductance trace for effective surge shunting. |
| Cathode | Protected-line interface terminal | Connected to input/power/signal line being protected; marked with cathode bar on top surface. |
Key Features
| Feature | Design Value |
|---|---|
| Flat STmite package (0.85 mm) | Enables placement in height-constrained spaces (e.g., stacked PCBs, sealed enclosures) without mechanical interference. |
| IEC 61000-4-2 level 4 compliance | Guarantees survivability against ±30 kV contact and air discharge - exceeds automotive EMC requirements (ISO 10605). |
| 175 °C maximum junction temperature | Supports long-term reliability in thermally aggressive environments (e.g., engine control units, solar inverters). |
| Low 0.2 µA leakage at 25 °C | Minimizes standby current draw in battery-powered IoT sensors and always-on monitoring circuits. |
| Planar junction construction | Delivers stable VBR and low parametric drift over temperature and lifetime versus diffused-junction alternatives. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Terminal |
|---|---|
Use Scenario: Protects 24 V supply rail and CAN/LIN bus lines from load dump and ISO 7637-2 pulses in vehicle door modules and lighting controllers. IC Role / Device Role / Timing Role: Unidirectional TVS placed between fused 24 V input and local LDO regulator input; clamps transients within 1 ns response time. Use Value: Prevents latch-up or permanent damage to microcontroller power domains during 12 V/24 V system switching events. |
Use Scenario: Shields 24 V digital input channels from field-wiring induced surges (e.g., relay coil flyback, lightning-induced coupling). IC Role / Device Role / Timing Role: Primary front-end protection element mounted directly at terminal block entry point; operates in parallel with optocoupler input stage. Use Value: Maintains functional safety integrity by limiting transient voltage to <45.4 V, ensuring optocoupler CMTI remains above 25 kV/µs. |
| Telecom Power Supply Input | Smart Meter Power Interface |
Use Scenario: Guards AC/DC adapter output and PoE-powered equipment inputs against conducted surges per IEC 61000-4-5 (Combination Wave 1.2/50 µs). IC Role / Device Role / Timing Role: Secondary-stage TVS after bulk MOV/clamp, handling residual fast-rising edges that bypass upstream protection. Use Value: Reduces risk of MOSFET gate oxide failure in synchronous rectifiers by limiting overshoot to ≤45.4 V during 8/20 µs transients. |
Use Scenario: Secures 24 V auxiliary power input of utility smart meters exposed to grid-switching transients and neutral-ground faults. IC Role / Device Role / Timing Role: Standalone protection on meter's external power connector; selected for low leakage to avoid false wake-up in sleep mode. Use Value: Extends battery backup runtime by contributing only 0.2 µA leakage at room temperature, meeting IEC 62053-21 Class 0.5S leakage limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A-TP (Microchip) | Same 28 V VRWM, but higher VCL = 48.4 V at 7.2 A; SMA package (2.2 mm height) vs. STmite Flat (0.85 mm). | Less suitable for ultra-low-profile designs; requires larger PCB footprint and higher mounting clearance. | Select when legacy SMA footprint compatibility is required and height constraint is relaxed. |
| SMLJ28A (Littelfuse) | Higher PPP = 1500 W (10/1000 µs); same VRWM/VCL but larger DO-214AB package (3.6 mm height, 4.2 mm width). | Better suited for high-energy surge zones (e.g., AC mains entry), not compact DC rail protection. | Choose only if system-level testing confirms need for >400 W rating and board space allows larger package. |
Compared with SMAJ28A-TP and SMLJ28A, the SMM4F28A-TR offers the lowest profile and tightest VCL specification among 28 V unidirectional TVS diodes, making it optimal for space-limited 24 V embedded systems where thermal management and PCB stack height are critical constraints.
Availability
SMM4F28A-TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O protection, and telecom power interface designs requiring stable component supply, consistent parametric performance across production lots, and full traceability to STMicroelectronics wafer fabrication.
Supply support for SMM4F28A-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, designing and manufacturing analog, MCU, power, and sensing solutions for automotive, industrial, and consumer markets.
The SMM4F series belongs to ST's high-reliability TVS portfolio targeting harsh-environment applications; it was engineered specifically for ultra-thin, high-temperature-stable surge protection in next-generation automotive and industrial control systems.
FAQ
What is the maximum clamping voltage of SMM4F28A-TR under a 10/1000 µs surge?
The maximum clamping voltage is 45.4 V at 8 A for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature per the coefficient αT = 9.8 × 10−4/°C, reaching approximately 49.2 V at Tj = 175 °C using the formula VCL(Tj) = VCL(25 °C) × [1 + αT × (Tj − 25)].
Is SMM4F28A-TR suitable for bidirectional signal line protection?
No - SMM4F28A-TR is a unidirectional TVS diode, configured for DC power rail or single-polarity signal protection. For bidirectional applications such as USB or RS-485 data lines, ST recommends the SMBJ28CA or SMCJ28CA series, which provide symmetrical clamping in both polarities.
What is the recommended PCB footprint for SMM4F28A-TR?
The official footprint uses a 2.04 mm × 0.85 mm pad layout with 0.75 mm solder mask opening, matching the STmite Flat mechanical outline (JEDEC MO-275). Thermal relief is advised on both pads, and copper area ≥2.5 cm² per lead is recommended to maintain Rth(j-a) ≤ 2.5 °C/W per Figure 11 in DS5630.
Does SMM4F28A-TR meet automotive AEC-Q200 qualification?
No - SMM4F28A-TR is not AEC-Q200 qualified. It is rated for industrial and commercial temperature ranges (−55 °C to +175 °C) and complies with IEC 61000-4-2/4-4, but lacks the extended reliability testing (e.g., temperature cycling, humidity bias) required for AEC-Q200 Grade 2 or Grade 1. For automotive-qualified equivalents, consider ST's Automotive-grade SMAJ28A-Q or SM8S28A-Q series.
SMM4F28A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-216AA
- Series:
- SMM4F, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.4V
- Voltage - Clamping (Max) @ Ipp:
- 59V
- Current - Peak Pulse (10/1000µs):
- 39A (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:
- DO-216AA
SMM4F28A-TR FAQ
1.How can I place an order for SMM4F28A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMM4F28A-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 SMM4F28A-TR reliable?
The price and inventory of SMM4F28A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMM4F28A-TR is usually 5 days.
3.What payment methods are accepted for SMM4F28A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMM4F28A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMM4F28A-TR?
SMM4F28A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMM4F28A-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 SMM4F28A-TR?
For technical support, including SMM4F28A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMM4F28A-TR requirements.
6.How does Aetrix verify that SMM4F28A-TR is sourced from the original manufacturer or authorized distributors?
All SMM4F28A-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 SMM4F28A-TR meets industry standards.
7.What is the process for return or replacement of SMM4F28A-TR?
All SMM4F28A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMM4F28A-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 SMM4F28A-TR part is unused and in its original packaging.
Return procedure for SMM4F28A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMM4F28A-TR Tags
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