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Taiwan Semiconductor Corporation SMF48A
- Part No.:
- SMF48A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF48A.pdf
- Description:
- TVS DIODE 48VWM 77.4VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:2,768
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Product details
Overview
SMF48A 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 48 V working stand-off voltage (VWM), 53.3–58.9 V breakdown voltage (VBR), 77.4 V clamping voltage (VC) at 2.6 A peak pulse current, and 200 W peak pulse power (10/1000 µs waveform). It is commonly deployed in automotive body electronics and industrial sensor interfaces requiring ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance.
For engineers reviewing the SMF48A datasheet, SMF48A pinout, SMF48A application, or SMF48A equivalent, key selection criteria include clamping performance under 10/1000 µs transients, junction temperature derating above 25°C, SOD-123W package thermal resistance (RθJL = 33°C/W), and reverse leakage (<1 µA at 48 V) in low-power standby circuits.
Technical Context
The SMF48A operates as a unidirectional avalanche diode, conducting only in reverse bias when transient voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low leakage (<1 µA at VWM), critical for battery-powered systems where quiescent current must be minimized.
Thermally, it is rated for TJ = –55°C to +175°C and mounted on a 5 mm × 5 mm copper pad per JEDEC test board conditions. Its RθJA = 100°C/W and RθJL = 33°C/W define thermal limits for sustained power dissipation (Ptot = 1 W) and short-duration surge handling (PPPM = 200 W).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 48 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 48 V systems. |
| VBR @ IT = 1 mA | 53.3–58.9 V - Breakdown voltage range at 1 mA test current; ensures reliable turn-on during fast transients. |
| VC @ IPPM = 2.6 A | 77.4 V - Clamped voltage at peak pulse current; determines maximum stress on downstream ICs during ISO 7637-2 Pulse 2b. |
| PPPM (10/1000 µs) | 200 W - Peak pulse power rating; supports robust protection against load dump and inductive switching surges. |
| IR @ VWM | <1 µA - Reverse leakage at 48 V; enables ultra-low standby power in always-on automotive modules. |
| Package | SOD-123W - Surface-mount package with matte tin-plated leads, J-STD-002 solderable, moisture sensitivity level 1. |
Pinout & Package
SOD-123W is a two-terminal surface-mount package with cathode indicated by a band. The device has no internal circuitry beyond the single silicon die; terminals are anode (unmarked end) and cathode (banded end).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side of protected line (e.g., ground or return path); conducts during forward surge events. |
| Cathode | Reverse breakdown terminal | Connected to higher-potential side (e.g., 48 V supply rail); initiates clamping when reverse voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over temperature and lifetime, with ±5% tolerance and minimal drift in harsh environments. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load disconnect), Pulse 2a/2b (battery feed interruption), and Pulse 3a/3b (switching transients) - required for automotive ECUs. |
| Low IR at VWM | <1 µA leakage at 48 V enables use in always-on circuits without compromising battery life in 12/24/48 V vehicle networks. |
| High thermal robustness | Junction-to-lead thermal resistance of 33°C/W allows efficient heat transfer to PCB copper, supporting repeated surge events without thermal runaway. |
Applications
| Automotive Body Control Module (BCM) | Industrial CAN Transceiver Protection |
|---|---|
Use Scenario: Protecting LIN bus power rails and microcontroller I/O pins from load dump and jump-start transients in door modules and seat controllers. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between 12 V supply and ground, triggered within nanoseconds to limit voltage to ≤77.4 V. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic ICs during ISO 7637-2 Pulse 2b (100 V, 100 ms) events. | Use Scenario: Safeguarding RS-485/CAN FD transceivers in factory automation gateways exposed to motor drive noise and relay switching spikes. IC Role / Device Role / Timing Role: Bidirectional protection not required; SMF48A used on VCC rail to suppress positive-going surges up to 200 W (10/1000 µs). Use Value: Maintains transceiver functionality during 40 V/100 ms transients while adding <0.5 mm² footprint and zero standby current penalty. |
| 48 V Mild Hybrid Power Distribution Unit | Smart Lighting Driver Input Stage |
Use Scenario: Guarding DC-DC controller inputs in 48 V starter-generator systems against alternator load dump (up to 60 V, 400 ms). IC Role / Device Role / Timing Role: Primary overvoltage clamp on main 48 V input rail, coordinated with upstream fusing and downstream ceramic filtering. Use Value: Limits peak rail voltage to 77.4 V, enabling use of 100 V-rated MOSFETs instead of costlier 150 V devices. | Use Scenario: Shielding LED driver ICs from ESD and lightning-induced surges on outdoor streetlight AC/DC front-ends. IC Role / Device Role / Timing Role: First-line transient suppressor on rectified DC bus, placed before bulk capacitor to absorb energy before it reaches control IC. Use Value: Withstands 200 W pulses without degradation, eliminating need for redundant MOVs and reducing BOM count by one component. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ48A | Same VWM (48 V), identical SOD-123 package, but higher VC = 79.4 V at 2.5 A; RθJA = 110°C/W. | Slightly higher clamping voltage reduces margin for 75 V-rated downstream components; lower thermal efficiency requires larger copper area. | Prefer SMF48A when tighter clamping or better thermal performance is needed on constrained PCBs. |
| Vishay SMA6J48A | Same VWM and SOD-123W package; VC = 77.4 V at 2.6 A (identical), but IR = 5 µA at VWM - 5× higher leakage. | Higher leakage may impact battery drain in always-on lighting nodes; otherwise functionally interchangeable for surge-only scenarios. | Choose SMF48A for ultra-low-power designs; SMA6J48A acceptable where leakage is not critical. |
Compared with SMAJ48A and SMA6J48A, the SMF48A delivers identical clamping performance with superior thermal resistance (33°C/W vs. ≥100°C/W) and lowest reverse leakage (<1 µA), making it optimal for thermally dense or battery-sensitive 48 V automotive and industrial applications.
Availability
SMF48A is available at Aetrix Electronics and suitable for automotive body electronics, industrial CAN node protection, and 48 V mild hybrid power distribution requiring stable component supply across multi-year production cycles.
Supply support for SMF48A 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and MOSFETs for automotive and industrial markets.
The SMF48A belongs to TSC's SMFxxA family of unidirectional TVS diodes engineered specifically for ISO 7637-2-compliant surge protection in 12 V, 24 V, and 48 V vehicle electrical architectures.
FAQ
What is the clamping voltage of the SMF48A under standard 10/1000 µs surge conditions?
The SMF48A clamps to 77.4 V at a peak pulse current (IPPM) of 2.6 A with a 10/1000 µs waveform. This value is measured per IEC 61000-4-5 and ISO 7637-2 test standards and defines the maximum voltage seen by protected circuitry during a defined transient event. The SMF48A maintains this clamping performance across its full operating temperature range (–55°C to +175°C), ensuring consistent protection in under-hood automotive environments.
Does the SMF48A meet automotive surge immunity standards?
Yes, the SMF48A meets ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a/2b (battery feed interruption), and Pulse 3a/3b (switching transients). Its 200 W peak pulse power rating, low clamping voltage, and glass-passivated junction were validated per these standards. The SMF48A is widely used in automotive body control modules and junction boxes where compliance with OEM-level EMC specifications is mandatory.
What is the maximum steady-state power dissipation for the SMF48A?
The SMF48A has a steady-state power dissipation (Ptot) of 1 W at lead temperature (TL) = 25°C, measured on a 5 mm × 5 mm copper pad test board. This rating applies to continuous DC or low-frequency operation and must be derated linearly above 25°C ambient using the RθJA = 100°C/W thermal resistance. For pulsed operation, the 200 W peak rating applies only to short-duration transients (≤1000 µs).
Is the SMF48A RoHS and halogen-free compliant?
Yes, the SMF48A is RoHS compliant and halogen-free per IEC 61249-2-21. Its molding compound meets UL 94V-0 flammability rating, and its matte tin-plated leads are solderable per J-STD-002. These compliance attributes make the SMF48A suitable for global automotive and industrial manufacturing, including EU and China RoHS-regulated supply chains.
What marking code identifies the SMF48A on the device body?
The SMF48A is marked with the code "2W048" on its SOD-123W package. This marking appears adjacent to the cathode band and is laser-etched for automated optical inspection. The "2W" prefix denotes the SMF series, "048" specifies the 48 V working voltage, and the cathode band confirms polarity orientation during placement.
SMF48A 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):
- 48V
- Voltage - Breakdown (Min):
- 53.3V
- Voltage - Clamping (Max) @ Ipp:
- 77.4V
- Current - Peak Pulse (10/1000µs):
- 2.6A
- 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
SMF48A FAQ
1.How can I place an order for SMF48A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF48A 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 SMF48A reliable?
The price and inventory of SMF48A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF48A is usually 5 days.
3.What payment methods are accepted for SMF48A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF48A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF48A?
SMF48A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF48A 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 SMF48A?
For technical support, including SMF48A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF48A requirements.
6.How does Aetrix verify that SMF48A is sourced from the original manufacturer or authorized distributors?
All SMF48A 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 SMF48A meets industry standards.
7.What is the process for return or replacement of SMF48A?
All SMF48A units undergo pre-shipment inspection (PSI). If there is an issue with SMF48A, 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 SMF48A part is unused and in its original packaging.
Return procedure for SMF48A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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