My Inquiry
My Account
STMicroelectronics SMM4F12A-TR
- Part No.:
- SMM4F12A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-222AA
- Datasheet:
-
SMM4F12A-TR.pdf
- Description:
- TVS DIODE 12VWM 25.3VC DO222-AA
- Quantity:
- Payment:
- Shipping:
Inventory:18,123
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMM4F12A-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 12 V, clamping voltage of 19.9 V at 20.1 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 electronics and industrial sensor interfaces.
For engineers reviewing the SMM4F12A-TR datasheet, SMM4F12A-TR pinout, SMM4F12A-TR application, or SMM4F12A-TR equivalent, key selection criteria include clamping performance under 10/1000 µs surges, thermal derating above 125 °C, flat-package footprint compatibility with high-density PCB layouts, and compliance with IEC 61000-4-2 Level 4 (±30 kV contact/air discharge).
Technical Context
This TVS diode uses planar silicon technology to achieve low leakage (<1 µA at 85 °C) and stable clamping across its full operating junction temperature range (–55 °C to +175 °C). Its dynamic resistance of 0.259 Ω (at 25 °C, 10/1000 µs) ensures predictable voltage limiting during fast transients.
The STmite Flat package enables high thermal dissipation despite its ultra-thin profile (0.85 mm max height), and its unidirectional configuration supports DC-biased signal or power line protection where reverse conduction must be blocked - unlike bidirectional variants used in AC-coupled or symmetric interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 12 V - maximum continuous reverse working voltage before breakdown; defines minimum system rail margin for reliable operation. |
| Breakdown Voltage (VBR) | 13.3–14.7 V at 1 mA - tight tolerance ensures consistent turn-on across production lots and temperature. |
| Clamping Voltage (VCL) | 19.9 V at 20.1 A (10/1000 µs) - peak voltage seen by protected circuit during standard lightning surge test. |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs), 2.5 kW (8/20 µs) - defines short-duration surge handling capability per IEC standards. |
| Leakage Current (IRM) | 0.2 µA at 25 °C, 1 µA at 85 °C - critical for battery-powered or high-impedance sensing nodes where standby current must be minimized. |
| Junction Temperature Range | –55 °C to +175 °C - supports under-hood automotive, motor drive, and industrial control environments without derating. |
| ESD Rating | ±30 kV (IEC 61000-4-2, contact & air) - exceeds Level 4 immunity requirements for user-accessible ports and connectors. |
Pinout & Package
STmite Flat surface-mount package: 2-terminal unidirectional TVS diode in a compact, low-profile outline (1.90 mm × 3.80 mm × 0.85 mm). Cathode marked with bar on top surface; anode and cathode are non-reversible terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side terminal | Connected to protected line (e.g., 12 V supply rail); conducts surge current toward cathode when reverse-biased beyond VBR. |
| Cathode | Ground/reference side terminal | Connected to system ground or low-impedance return path; defines polarity-sensitive clamping direction for DC applications. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low profile | 0.85 mm max height - enables placement beneath connectors or in space-constrained modules without mechanical interference. |
| High-temperature reliability | Rated for 175 °C junction operation - eliminates thermal derating in engine control units and industrial PLCs. |
| Low dynamic resistance | 0.259 Ω (25 °C, 10/1000 µs) - minimizes clamping voltage rise under high-current surges, improving protection margin. |
| Matte tin lead finish | RoHS-compliant, whisker-resistant plating - ensures solderability and long-term interconnect integrity per JESD201 Class 2. |
| IEC 61000-4-4 immunity | 4 kV (EFT) rating - protects against repetitive electrical fast transients in motor drives and power supply inputs. |
Applications
| Automotive Body Control Module (BCM) | Industrial Sensor Interface |
|---|---|
|
Use Scenario: Protecting LIN bus lines and 12 V power inputs in door modules and lighting controllers exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between power rail and ground to limit transient overvoltage during alternator load dump events. Use Value: Clamps to ≤19.9 V at 20.1 A, preventing damage to LIN transceivers and microcontroller I/O pins rated for 16 V absolute maximum. |
Use Scenario: Safeguarding analog sensor outputs (e.g., pressure, temperature) connected to 24 V industrial PLC inputs subject to field wiring surges. IC Role / Device Role / Timing Role: Standoff-rated TVS on sensor output line to suppress induced transients from nearby relay switching or motor commutation. Use Value: 0.2 µA leakage at 25 °C avoids signal offset errors in µA-level current-loop sensors; 175 °C rating supports enclosure mounting near heat sources. |
| USB-C Power Delivery Port | Smart Meter Communication Interface |
|
Use Scenario: Secondary-level surge protection on VBUS line downstream of primary protection, meeting USB-IF ESD requirements for hot-plug resilience. IC Role / Device Role / Timing Role: Fast-response unidirectional clamp absorbing contact ESD (±30 kV) while maintaining low capacitance (<100 pF at 1 V) to avoid signal integrity degradation. Use Value: 19.9 V clamping ensures PD controller ICs (e.g., TUSB9261) remain within safe operating area during repeated plug/unplug cycles. |
Use Scenario: Protecting RS-485 transceivers in utility smart meters installed in outdoor cabinets vulnerable to lightning-induced surges on communication lines. IC Role / Device Role / Timing Role: Line-to-ground TVS on differential pair to shunt common-mode surges without disrupting data integrity. Use Value: 2.5 kW (8/20 µs) peak power rating handles high-energy induced surges typical in overhead power line deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A | Higher clamping voltage (23.2 V at 17.3 A), larger SMA package (2.4 mm height), lower PPP (400 W only at 10/1000 µs) | Less suitable for space-constrained designs; higher VCL reduces protection margin for 16 V-rated ICs | Choose if legacy SMA footprint is fixed and thermal budget allows taller profile. |
| SMCJ12A | Same 12 V VRM but higher PPP (1500 W at 10/1000 µs), larger SMC package (2.6 mm height), higher leakage (1 µA at 25 °C) | Better for high-energy surges but incompatible with ultra-thin PCB assemblies and battery-sensitive systems | Prefer when surge energy exceeds 400 W and board height >2.5 mm is acceptable. |
Compared with SMAJ12A and SMCJ12A, the SMM4F12A-TR delivers superior height efficiency (0.85 mm), tighter clamping (19.9 V), and lower leakage - making it optimal for next-gen automotive ECUs and portable industrial devices where volume and quiescent current are critical.
Availability
SMM4F12A-TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, USB-C power delivery ports, and smart meter communication interfaces requiring stable component supply across extended temperature ranges and high-reliability production programs.
Supply support for SMM4F12A-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, delivering intelligent power, sensing, and connectivity solutions for automotive, industrial, and consumer markets.
The SMM4F series belongs to ST's STmite Flat TVS portfolio, engineered specifically for high-density, thermally demanding applications where low-profile packaging, high-temperature operation, and precise clamping performance are essential.
FAQ
What is the maximum clamping voltage for SMM4F12A-TR under a 10/1000 µs surge?
The maximum clamping voltage is 19.9 V at 20.1 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature due to the positive temperature coefficient (αT = 8.3 × 10⁻⁴ /°C), reaching ~21.5 V at 125 °C junction temperature per the VCL vs. Tj formula in DS5630.
Can SMM4F12A-TR be used in bidirectional signal lines like RS-485?
No - SMM4F12A-TR is unidirectional and blocks conduction in forward bias. For bidirectional lines such as RS-485, a bidirectional variant (e.g., SMM4F12AY-TR) or dual-diode configuration is required to protect both polarities of transient events without rectifying the signal.
Does the STmite Flat package require special PCB layout considerations?
Yes - the recommended footprint (DS5630 Figure 13) specifies 0.75 mm pad width and 2.04 mm pad length with 0.8 mm spacing. Thermal performance depends critically on copper area under each lead; ≥2 cm² per pad reduces Rth(j-a) to <2.5 °C/W, enabling full 400 W surge capability at elevated temperatures.
Is SMM4F12A-TR compliant with AEC-Q200 for automotive use?
While SMM4F12A-TR meets key automotive stress requirements (175 °C Tj max, ±30 kV ESD, IEC 61000-4-4), it is not officially AEC-Q200 qualified. ST offers the automotive-grade AEC-Q200 version under part number SMAJ12A-Q - verify qualification status via ST's official automotive product database before deployment in safety-critical vehicle systems.
SMM4F12A-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):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 25.3V
- Current - Peak Pulse (10/1000µs):
- 91A (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
SMM4F12A-TR FAQ
1.How can I place an order for SMM4F12A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMM4F12A-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 SMM4F12A-TR reliable?
The price and inventory of SMM4F12A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMM4F12A-TR is usually 5 days.
3.What payment methods are accepted for SMM4F12A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMM4F12A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMM4F12A-TR?
SMM4F12A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMM4F12A-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 SMM4F12A-TR?
For technical support, including SMM4F12A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMM4F12A-TR requirements.
6.How does Aetrix verify that SMM4F12A-TR is sourced from the original manufacturer or authorized distributors?
All SMM4F12A-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 SMM4F12A-TR meets industry standards.
7.What is the process for return or replacement of SMM4F12A-TR?
All SMM4F12A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMM4F12A-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 SMM4F12A-TR part is unused and in its original packaging.
Return procedure for SMM4F12A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMM4F12A-TR Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
