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Taiwan Semiconductor Corporation SMF18AH
- Part No.:
- SMF18AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF18AH.pdf
- Description:
- TVS DIODE 18VWM 29.2VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:2,999
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Product details
Overview
SMF18AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SOD-123W package, rated for 18 V working stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 29.2 V clamping voltage (VC) at 6.8 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It protects automotive-grade electronics against ISO 7637-2 pulses and ESD transients.
For engineers reviewing the SMF18AH datasheet, SMF18AH pinout, SMF18AH application, or SMF18AH equivalent, key selection criteria include clamping performance under 10/1000 µs surge, AEC-Q101 qualification, low leakage (<1 µA @ 18 V), thermal resistance (RθJL = 33 °C/W), and compatibility with automated SMT assembly on PCBs with 5 mm × 5 mm copper pads.
Technical Context
The SMF18AH operates as a unidirectional avalanche-clamping device, activated when reverse voltage exceeds its 20.0–22.1 V breakdown threshold. Its glass-passivated junction ensures stable VBR tolerance and low leakage (<1 µA at 18 V), critical for low-power system monitoring circuits.
Designed for automotive load-dump and inductive-switching transient suppression, it meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b waveforms and delivers 29.2 V clamping at 6.8 A IPPM - enabling robust protection of CAN/LIN transceivers, microcontroller I/O, and sensor interfaces without overvoltage stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 20.0 V / 22.1 V - guaranteed avalanche initiation range at 1 mA test current |
| VC @ IPPM | 29.2 V at 6.8 A - peak clamped voltage during 10/1000 µs surge, limiting downstream IC stress |
| PPPM | 200 W - surge energy handling capacity per single 10/1000 µs pulse |
| IR @ VWM | <1 µA - minimal leakage current ensures negligible standby power loss in battery-critical systems |
| RθJL | 33 °C/W - junction-to-lead thermal resistance enables reliable 1 W steady-state dissipation on standard PCB pad |
Pinout & Package
Package: SOD-123W - surface-mount, single-diode, cathode-banded case with matte tin-plated leads (J-STD-002 compliant), UL 94V-0 molding compound, and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction path | Connected to protected circuit ground or low-side return; defines unidirectional polarity |
| Cathode | Clamping node | Connected to protected line (e.g., CAN_H, LIN bus, sensor supply); conducts surge current to ground when VREV > VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood and cabin applications per stress test requirements |
| Glass-passivated junction | Ensures stable VBR over temperature and lifetime, reducing parameter drift in harsh environments |
| Low IR <1 µA @ VWM | Minimizes quiescent current draw in always-on vehicle modules (e.g., body control units) |
| ISO 7637-2 compliance | Guarantees immunity to real-world automotive transients including load dump and inductive kickback |
| SOD-123W footprint | Enables high-density placement and compatibility with standard pick-and-place equipment and reflow profiles |
Applications
| Automotive CAN Bus Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protecting high-speed CAN_H/CAN_L lines from battery load dump and ESD events in 12 V vehicle networks. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between CAN transceiver pins and chassis ground. Use Value: Limits transient voltage to ≤29.2 V, preserving CAN physical layer integrity and preventing bit errors or transceiver latch-up. | Use Scenario: Safeguarding microcontroller GPIOs and sensor inputs (e.g., door lock actuators, ambient light sensors) from inductive switching noise. IC Role / Device Role / Timing Role: Standoff-protection element on 5–18 V supply rails and signal lines within BCM PCBs. Use Value: Withstands repeated ISO 7637-2 Pulse 3b (capacitive coupling) surges while drawing <1 µA leakage during sleep mode. |
| LED Headlamp Driver Protection | Automotive LIN Bus Interface |
Use Scenario: Shielding buck/boost LED driver ICs from voltage spikes generated by relay coil de-energization in headlamp assemblies. IC Role / Device Role / Timing Role: Parallel-connected TVS across driver output stage to clamp flyback energy. Use Value: 200 W PPPM rating absorbs 10/1000 µs inductive spikes without degradation, maintaining LED reliability over 15-year service life. | Use Scenario: Securing LIN transceiver inputs against ESD and slow-rising transients in seat control or mirror adjustment modules. IC Role / Device Role / Timing Role: Low-capacitance unidirectional clamp on LIN bus line referenced to local ground. Use Value: 29.2 V clamping voltage stays below LIN transceiver absolute max rating (typically 36 V), ensuring fault-free communication during EMC testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Same VWM (18 V), but higher VC = 32.4 V; SMA package (larger footprint, RθJA = 110 °C/W) | Less suitable for space-constrained automotive modules; lower thermal efficiency limits sustained surge duty cycle | Prefer SMF18AH where board area and thermal performance are critical |
| 1.5SMC18A | Higher PPPM (1500 W), DO-214AB package; VWM = 18 V, VC = 29.2 V - identical clamping but larger size and higher IR (5 µA) | Better for high-energy industrial surges; not AEC-Q101 qualified; unsuitable for automotive qualification programs | Choose SMF18AH for automotive-compliant designs requiring validated reliability and SMT scalability |
Compared with SMAJ18A and 1.5SMC18A, the SMF18AH offers superior thermal performance (RθJL = 33 °C/W), AEC-Q101 qualification, and SOD-123W compactness - making it optimal for automotive ECUs where footprint, leakage, and qualification traceability are design-critical.
Availability
SMF18AH is available at Aetrix Electronics and suitable for automotive CAN bus protection, body control module (BCM) transient suppression, and LED headlamp driver safeguarding requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMF18AH 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, MOSFETs, and automotive-qualified components.
The SMF18AH belongs to TSC's SMF-AH series of AEC-Q101-qualified TVS diodes, engineered specifically for automotive electronic control units requiring high-reliability, low-leakage transient suppression in space- and thermal-constrained layouts.
FAQ
What is the breakdown voltage range for SMF18AH?
The SMF18AH has a guaranteed breakdown voltage (VBR) range of 20.0 V to 22.1 V at 1 mA test current, measured per JEDEC standards. This tight tolerance ensures consistent clamping behavior across production lots and supports robust design margins in automotive applications where voltage regulation must remain predictable under temperature variation and aging.
Is SMF18AH suitable for bidirectional transient protection?
No, SMF18AH is a unidirectional TVS diode and only provides protection against reverse-polarity transients on the cathode side. For bidirectional protection (e.g., data lines with AC signals), a dedicated bidirectional variant such as SMF18A or a dual-diode configuration is required. The SMF18AH's marking code "2W018" and cathode band confirm its unidirectional construction.
Does SMF18AH meet automotive qualification standards?
Yes, SMF18AH is AEC-Q101 qualified and tested per the full stress test schedule for discrete semiconductors, including HTOL, temperature cycling, and mechanical shock. It also meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements - confirming its suitability for deployment in automotive powertrain, chassis, and body electronics per OEM specifications.
What is the maximum clamping voltage of SMF18AH under surge conditions?
The SMF18AH clamps to a maximum of 29.2 V when subjected to a 10/1000 µs surge waveform at 6.8 A peak pulse current (IPPM). This value is specified in the manufacturer's electrical characteristics table and verified across temperature and lot variations, ensuring downstream ICs (e.g., CAN transceivers rated to 36 V abs max) remain within safe operating limits during real-world transients.
Can SMF18AH be used in industrial applications outside automotive?
Yes, SMF18AH is widely deployed in industrial motor drives, PLC I/O modules, and smart lighting systems where its 200 W peak pulse rating, low leakage (<1 µA), and SOD-123W package provide reliable transient suppression. While AEC-Q101 qualification adds confidence for mission-critical use, its electrical specs and RoHS/halogen-free compliance make SMF18AH equally viable for non-automotive high-reliability designs.
SMF18AH 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 6.8A
- Power - Peak Pulse:
- 200W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123W
SMF18AH FAQ
1.How can I place an order for SMF18AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF18AH 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 SMF18AH reliable?
The price and inventory of SMF18AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF18AH is usually 5 days.
3.What payment methods are accepted for SMF18AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF18AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF18AH?
SMF18AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF18AH 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 SMF18AH?
For technical support, including SMF18AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF18AH requirements.
6.How does Aetrix verify that SMF18AH is sourced from the original manufacturer or authorized distributors?
All SMF18AH 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 SMF18AH meets industry standards.
7.What is the process for return or replacement of SMF18AH?
All SMF18AH units undergo pre-shipment inspection (PSI). If there is an issue with SMF18AH, 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 SMF18AH part is unused and in its original packaging.
Return procedure for SMF18AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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