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Taiwan Semiconductor Corporation SMF26A
- Part No.:
- SMF26A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF26A.pdf
- Description:
- TVS DIODE 26VWM 42.1VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:8,199
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Product details
Overview
SMF26A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy ESD and surge protection in DC power lines and signal paths. It features a 26V working stand-off voltage (VWM), 28.9–31.9V breakdown voltage (VBR), 42.1V clamping voltage (VC) at 4.8A peak pulse current, and 200W peak pulse power (10/1000μs). It is commonly deployed in automotive body electronics and industrial I/O interfaces requiring robust ISO 7637-2 Pulse 1/2a/2b/3a/3b immunity.
For engineers reviewing the SMF26A datasheet, SMF26A pinout, SMF26A application, or SMF26A equivalent, key selection criteria include verified clamping performance under 10/1000μs transients, SOD-123W package thermal resistance (RθJA = 100°C/W), low leakage (<1μA @ 26V), and compliance with J-STD-020 moisture sensitivity level 1 - all critical for high-reliability embedded power rail protection.
Technical Context
The SMF26A operates as a unidirectional avalanche diode, conducting only in reverse bias above its breakdown threshold to shunt transient energy to ground. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low leakage, while the SOD-123W package enables automated placement and delivers RθJL = 33°C/W for effective thermal dissipation during repetitive surges.
It meets ISO 7637-2 test pulses without external series impedance, supporting direct integration into 12V/24V automotive subsystems. The device's 175°C maximum junction temperature and -55°C to +175°C operating range allow deployment in under-hood and industrial control environments where thermal cycling and long-term reliability are essential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 26 V - Maximum continuous reverse voltage before clamping begins; defines safe operating margin for 24V nominal systems. |
| VBR min/max | 28.9 V / 31.9 V - Breakdown occurs within this band at 1 mA test current; ensures predictable turn-on across temperature and lot variation. |
| VC @ IPPM | 42.1 V - Clamped voltage at 4.8 A peak pulse (10/1000μs); limits downstream IC stress during worst-case transients. |
| PPPM | 200 W - Peak pulse power handling capability; supports high-energy surges per ISO 7637-2 Pulse 1 and 2b. |
| IR @ VWM | <1 μA - Reverse leakage at rated stand-off voltage; minimizes quiescent power loss in battery-powered systems. |
| TJ max | +175 °C - Maximum junction temperature; enables operation in high-ambient environments like engine control units. |
| Package | SOD-123W - Surface-mount outline with enhanced thermal pad; provides 33°C/W junction-to-lead resistance for PCB-level heat transfer. |
Pinout & Package
SOD-123W is a single-diode, two-terminal surface-mount package with cathode indicated by a band. The device has no internal circuitry beyond the avalanche junction; terminals are anode (unmarked end) and cathode (banded end).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to protected line (e.g., 24V rail); conducts forward current only during fault conditions in unidirectional configuration. |
| Cathode | Reverse-biased clamping terminal | Connected to ground or lower-potential reference; initiates avalanche conduction when reverse voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Photo glass passivation | Ensures stable VBR and low IR over lifetime and humidity exposure; eliminates surface leakage paths in harsh environments. |
| ISO 7637-2 compliance | Validated against Pulse 1 (inductive load dump), Pulse 2a (battery disconnect), Pulse 2b (load dump with suppression), Pulse 3a/3b (capacitive coupling); no external components required. |
| J-STD-020 Level 1 MSL | Zero floor life limitation; can be stored indefinitely at ≤30°C/60% RH and mounted without baking or special handling. |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive; suitable for green manufacturing and export to regulated markets. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting LIN bus transceivers and microcontroller GPIOs from load dump and ESD events in door modules and lighting controllers. IC Role / Device Role / Timing Role: Unidirectional TVS placed between LIN line and ground to clamp transients before they reach the transceiver input stage. Use Value: Limits clamped voltage to 42.1 V at 4.8 A, ensuring LIN PHY remains within absolute maximum ratings during ISO 7637-2 Pulse 2b (100 V, 50 ms). | Use Scenario: Safeguarding 24V digital input channels on programmable logic controller (PLC) I/O cards exposed to field wiring surges. IC Role / Device Role / Timing Role: Primary surge clamp on each input channel, located upstream of optocoupler or Schmitt trigger input conditioning. Use Value: Absorbs 200 W peak pulse energy (10/1000μs), preventing latch-up or permanent damage to input buffer ICs during inductive switching events. |
| Smart Meter Power Supply Rail | Medical Diagnostic Equipment Interface |
Use Scenario: Protecting the 24V auxiliary supply rail in electricity meters from induced surges on AC mains-connected communication ports. IC Role / Device Role / Timing Role: Secondary-level TVS on DC-DC converter output, complementing primary MOV-based AC-side protection. Use Value: Low 1 μA leakage at 26 V preserves battery backup runtime; fast response (<1 ns) prevents voltage overshoot from propagating to metering ICs. | Use Scenario: Shielding RS-485 communication lines in portable ultrasound or patient monitor devices from ESD and cable discharge events. IC Role / Device Role / Timing Role: Point-of-entry TVS on differential pair, placed immediately after connector to minimize stub length and preserve signal integrity. Use Value: 42.1 V clamping ensures RS-485 transceiver stays within ±12 V common-mode range; SOD-123W footprint allows tight layout near connector. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ26A (Bourns) | Same VWM (26 V), but SMB package (larger footprint, RθJA = 50°C/W); higher IPPM (12.3 A) and VC (42.8 V). | Preferred where higher thermal mass or legacy SMB footprint is required; less suitable for ultra-dense layouts. | Select SMBJ26A if board space permits larger package and higher steady-state power handling is needed. |
| P6SMB26A (ON Semiconductor) | Identical electrical specs (VWM = 26 V, VC = 42.1 V), same SOD-123W package, but rated for 175 W PPPM (vs. 200 W). | Valid for most ISO 7637-2 applications except highest-energy Pulse 1 scenarios; identical mounting and reflow profile. | Choose P6SMB26A when sourcing diversification is prioritized and 175 W pulse rating suffices for target threat model. |
Compared with SMBJ26A and P6SMB26A, the SMF26A offers the highest peak pulse power (200 W) in the smallest standard TVS footprint (SOD-123W), enabling compact, thermally efficient designs for space-constrained automotive and industrial modules without sacrificing clamping performance.
Availability
SMF26A is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC inputs, smart meter power rails, and medical interface protection requiring stable component supply and full traceability.
Supply support for SMF26A 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for industrial, automotive, and consumer applications.
The SMF26A belongs to TSC's SMF-series unidirectional TVS family, engineered specifically for high-reliability, high-surge immunity in 12V/24V systems compliant with ISO 7637-2 and IEC 61000-4-2 standards.
FAQ
What is the maximum clamping voltage of the SMF26A under standard test conditions?
The SMF26A exhibits a maximum clamping voltage (VC) of 42.1 V when subjected to a 10/1000 μs waveform at its rated peak pulse current of 4.8 A. This value is measured per JEDEC standards and guarantees that downstream circuitry remains within safe voltage limits during transient events. The SMF26A maintains this clamping performance across its specified operating temperature range (-55°C to +175°C), making it suitable for under-hood automotive use.
Does the SMF26A meet automotive surge immunity standards?
Yes, the SMF26A is explicitly validated to meet ISO 7637-2 requirements for Pulses 1, 2a, 2b, 3a, and 3b - covering load dump, battery disconnection, and capacitive coupling transients common in 12V/24V vehicle networks. Its 200 W peak pulse power rating and low clamping voltage ensure robust protection without additional external components. The SMF26A is widely used in automotive BCMs and sensor modules where such compliance is mandatory.
What is the moisture sensitivity level (MSL) rating for the SMF26A?
The SMF26A carries a J-STD-020 Moisture Sensitivity Level 1 rating, meaning it has unlimited floor life when stored at ≤30°C and ≤60% relative humidity. No baking or dry-pack requirements apply prior to reflow soldering. This simplifies manufacturing logistics and eliminates yield risk from popcorning during assembly - a key advantage over MSL 2 or higher TVS diodes. The SMF26A's SOD-123W package construction directly supports this MSL 1 classification.
How does the SMF26A compare to bidirectional TVS diodes in terms of application scope?
The SMF26A is unidirectional and optimized for DC power line and single-ended signal protection where polarity is fixed (e.g., 24V supply rails, LIN bus). Unlike bidirectional variants, it provides lower leakage (<1 μA at 26 V) and tighter VBR tolerance, improving efficiency and noise margin. Bidirectional TVS diodes are reserved for AC or floating signals (e.g., USB D+/D−, RS-485). The SMF26A should not be substituted for bidirectional types without verifying circuit polarity and transient directionality.
Can the SMF26A be used in parallel to increase surge current handling?
No - the SMF26A is not recommended for parallel operation due to inherent VBR mismatch between units, which causes uneven current sharing and potential thermal runaway. For higher IPPM requirements, select a single higher-rated device (e.g., SMF33A or SMF36A) or implement staged protection with series impedance. The SMF26A's design assumes standalone use per protected node; its 200 W PPPM rating is fully characterized for individual device operation under JEDEC-defined waveforms.
SMF26A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- SOD-123W
- Series:
- SMF
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 26V
- Voltage - Breakdown (Min):
- 28.9V
- Voltage - Clamping (Max) @ Ipp:
- 42.1V
- Current - Peak Pulse (10/1000µs):
- 4.8A
- Power - Peak Pulse:
- 200W
- 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:
- SOD-123W
SMF26A FAQ
1.How can I place an order for SMF26A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF26A 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 SMF26A reliable?
The price and inventory of SMF26A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF26A is usually 5 days.
3.What payment methods are accepted for SMF26A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF26A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF26A?
SMF26A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF26A 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 SMF26A?
For technical support, including SMF26A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF26A requirements.
6.How does Aetrix verify that SMF26A is sourced from the original manufacturer or authorized distributors?
All SMF26A 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 SMF26A meets industry standards.
7.What is the process for return or replacement of SMF26A?
All SMF26A units undergo pre-shipment inspection (PSI). If there is an issue with SMF26A, 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 SMF26A part is unused and in its original packaging.
Return procedure for SMF26A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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