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STMicroelectronics SMM4F33A-TR
- Part No.:
- SMM4F33A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-222AA
- Datasheet:
-
SMM4F33A-TR.pdf
- Description:
- TVS DIODE 33VWM 69.7VC DO222-AA
- Quantity:
- Payment:
- Shipping:
Inventory:34,108
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Product details
Overview
SMM4F33A-TR 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 standoff voltage of 33 V, clamping voltage of 53.3 V at 7 A (10/1000 µs), low leakage current (0.2 µA at 25 °C), and operates up to 175 °C junction temperature - ideal for automotive body control modules and industrial PLC I/O protection.
For engineers reviewing the SMM4F33A-TR datasheet, SMM4F33A-TR pinout, SMM4F33A-TR application, or SMM4F33A-TR equivalent, key selection criteria include clamping performance at elevated temperature, dynamic resistance (1.76 Ω), peak pulse power derating above 25 °C, and STmite Flat package compatibility with high-density PCB layouts.
Technical Context
This TVS diode uses planar silicon technology to achieve stable breakdown behavior and low leakage across its -55 °C to +175 °C operating junction range. Its unidirectional configuration provides asymmetric clamping - forward conduction only during negative transients - enabling precise polarity-aware protection in regulated 3.3 V–33 V supply domains.
The device's thermal design supports sustained reliability under repeated surges: maximum lead temperature is rated at 260 °C for 10 s, and thermal impedance junction-to-ambient is 100 °C/W on standard FR4 with recommended copper footprint. Dynamic resistance (RD = 1.76 Ω) directly governs clamping voltage rise under high-current transients per VCL(max) = VBR(max) + RD × IPP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRWM) | 33 V - Maximum continuous reverse working voltage before clamping initiates |
| Breakdown Voltage (VBR) | 37.1–41.0 V at 1 mA - Confirmed minimum/maximum threshold for avalanche conduction |
| Clamping Voltage (VCL) | 53.3 V at 7 A (10/1000 µs) - Peak voltage seen by protected circuit during standardized surge |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - Sustained surge energy handling at Tj = 25 °C |
| Dynamic Resistance (RD) | 1.76 Ω - Determines VCL slope vs. IPP; critical for precision clamping design |
| Leakage Current (IR) | 0.2 µA at 25 °C, 1 µA at 85 °C - Low standby loss for battery-backed or low-power systems |
| Junction Temperature Range | -55 °C to +175 °C - Enables deployment in under-hood automotive or industrial motor drive environments |
Pinout & Package
STmite Flat surface-mount package (JEDEC MO-275 compatible), dimensions: 3.80 mm × 1.90 mm × 0.85 mm (L × W × H), matte tin-plated leads, MSL Level 1, UL94 V0 rated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry during forward surge | Connected to protected line (e.g., CAN_H, 24 V rail); conducts only during negative transients |
| Cathode | Current exit during reverse surge | Connected to ground reference; defines clamping path for positive ESD/surge events |
Key Features
| Feature | Design Value |
|---|---|
| Flat and thin profile (0.85 mm height) | Enables placement beneath connectors or in ultra-thin enclosures without mechanical interference |
| High surge immunity (30 kV contact/air discharge) | Meets IEC 61000-4-2 Level 4 without external filtering - reduces BOM count in ESD-critical ports |
| Low dynamic resistance (1.76 Ω) | Minimizes clamping voltage overshoot under fast-rising 8/20 µs surges (e.g., lightning-induced) |
| Extended junction temperature rating (175 °C) | Supports operation near heat sources (e.g., power converters) without derating or thermal shutdown |
| Lead-free and RoHS-compliant | Complies with J-STD-020 MSL Level 1 and IPC7531 footprint standards for automated assembly |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting 24 V sensor supply lines against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary clamping element placed between power rail and local LDO input. Use Value: Limits transient voltage to ≤53.3 V, preventing LDO overvoltage failure and ensuring system uptime during vehicle cranking events. | Use Scenario: Safeguarding 24 V digital input channels from field-wiring induced surges and ESD. IC Role / Device Role / Timing Role: Front-end transient suppressor before optocoupler or Schmitt trigger input stage. Use Value: Clamps 4 kV IEC 61000-4-4 bursts to safe levels, eliminating false triggering and extending input stage lifetime. |
| Smart Meter Power Supply | Telecom Remote Terminal Unit (RTU) |
Use Scenario: Securing AC/DC converter secondary-side 33 V bias rail against coupling from mains transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed across bulk capacitor output. Use Value: Absorbs 400 W surges without degradation, maintaining meter accuracy and certification compliance over 10+ year field life. | Use Scenario: Shielding RS-485 communication lines in outdoor substations exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Line-side TVS on differential pair, referenced to local ground plane. Use Value: Withstands 30 kV air discharge per IEC 61000-4-2, preserving data integrity during thunderstorms without requiring gas discharge tubes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33A | Higher clamping voltage (59.3 V @ 6.4 A), larger SMA package (2.5 mm height), lower PPP (400 W same, but derates faster above 25 °C) | Less suitable for space-constrained designs; higher thermal resistance limits sustained surge duty cycle | Select when legacy SMA footprint is fixed and 0.85 mm height is not required |
| 1.5SMC33A | Same VRWM and VCL, but DO-214AB package (4.5 mm height), higher leakage (1 µA @ 25 °C), lower Tjmax (150 °C) | Not qualified for under-hood automotive use; unsuitable for high-temperature industrial enclosures | Choose only for cost-sensitive, non-automotive applications where board height >4 mm is acceptable |
Compared with SMAJ33A and 1.5SMC33A, SMM4F33A-TR delivers superior thermal performance (175 °C Tjmax), lower profile (0.85 mm), and tighter clamping (53.3 V vs. 59.3 V/58.1 V), making it optimal for next-generation compact, high-reliability power rail protection.
Availability
SMM4F33A-TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, smart meter power supplies, and telecom RTUs requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SMM4F33A-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 vertical manufacturing and broad IP portfolio.
The SMM4F series belongs to ST's STmite Flat TVS portfolio, engineered specifically for high-density, high-temperature PCB layouts where low-profile surge protection with minimal leakage and robust IEC/ISO compliance is mandatory.
FAQ
What is the maximum clamping voltage of SMM4F33A-TR under an 8/20 µs surge?
The maximum clamping voltage is 69.7 V at 45 A for an 8/20 µs waveform, as specified in Table 2 of DS5630 Rev 6. This value reflects worst-case VCL under high-current, fast-rising transients typical of lightning-induced surges, and must be verified against downstream IC absolute maximum ratings.
Does SMM4F33A-TR support reflow soldering per JEDEC J-STD-020?
Yes - it is rated MSL Level 1 with no floor life limitation and qualified for standard Pb-free reflow profiles up to 245 °C peak, as shown in Figure 20 of DS5630. The STmite Flat package withstands ramp rates up to 3 °C/s and dwell time ≤90 seconds at peak temperature.
How does junction temperature affect clamping voltage?
VCL increases linearly with junction temperature per coefficient αT = 10 × 10−4/°C. At 175 °C, VCL rises ~15% above its 25 °C value (53.3 V → ~61.3 V), which must be accounted for in worst-case surge margin analysis for high-temperature deployments.
Is SMM4F33A-TR suitable for bidirectional signal line protection?
No - it is unidirectional only. For bidirectional protection (e.g., USB, RS-232), a symmetric TVS like SMBJ33CA or dual-diode array is required. Using SMM4F33A-TR on AC-coupled or differential lines risks forward conduction during negative half-cycles and potential latch-up.
SMM4F33A-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):
- 33V
- Voltage - Breakdown (Min):
- 37.1V
- Voltage - Clamping (Max) @ Ipp:
- 69.7V
- Current - Peak Pulse (10/1000µs):
- 33A (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:
- DO222-AA
SMM4F33A-TR FAQ
1.How can I place an order for SMM4F33A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMM4F33A-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 SMM4F33A-TR reliable?
The price and inventory of SMM4F33A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMM4F33A-TR is usually 5 days.
3.What payment methods are accepted for SMM4F33A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMM4F33A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMM4F33A-TR?
SMM4F33A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMM4F33A-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 SMM4F33A-TR?
For technical support, including SMM4F33A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMM4F33A-TR requirements.
6.How does Aetrix verify that SMM4F33A-TR is sourced from the original manufacturer or authorized distributors?
All SMM4F33A-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 SMM4F33A-TR meets industry standards.
7.What is the process for return or replacement of SMM4F33A-TR?
All SMM4F33A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMM4F33A-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 SMM4F33A-TR part is unused and in its original packaging.
Return procedure for SMM4F33A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMM4F33A-TR Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
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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DESD5V0U1BB-7
Diodes Incorporated
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D12V0L1B2LP-7B
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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