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Taiwan Semiconductor Corporation SMF85AH
- Part No.:
- SMF85AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF85AH.pdf
- Description:
- TVS DIODE 85VWM 137VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:2,394
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Product details
Overview
SMF85AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SOD-123W package, rated for 85 V working stand-off voltage (VWM), 94.4–104 V breakdown voltage (VBR), and 137 V clamping voltage (VC) at 1.3 A peak pulse current. It delivers 200 W peak pulse power (10/1000 µs), supports AEC-Q101 qualification, and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive load-dump and switching transient protection.
For engineers reviewing the SMF85AH datasheet, SMF85AH pinout, SMF85AH application, or SMF85AH equivalent, this device is selected for robust ESD and electrical fast transient (EFT) immunity in automotive body control modules, LED lighting drivers, and industrial sensor interfaces where low leakage (<1 µA @ 85 V), high clamping efficiency, and SMT manufacturability are critical.
Technical Context
The SMF85AH operates as a unidirectional avalanche diode with glass-passivated junction for stable breakdown behavior under repetitive transients. Its thermal design targets TJ ≤ 175 °C max, supported by RθJL = 33 °C/W and RθJA = 100 °C/W on a 5 mm × 5 mm Cu pad PCB.
It is characterized for 10/1000 µs waveform compliance per IEC 61000-4-5 and ISO 7637-2, with clamping performance validated at IPPM = 1.3 A and VC = 137 V - enabling reliable protection of 12 V/24 V automotive electronics against load dump and inductive kickback.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR min / max | 94.4 V / 104 V - guaranteed avalanche onset range at IT = 1 mA, ensuring predictable turn-on |
| VC @ IPPM | 137 V - clamped voltage at 1.3 A peak pulse, limiting downstream stress to safe levels |
| PPPM | 200 W - peak pulse power handling (10/1000 µs), sufficient for ISO 7637-2 Pulse 5a |
| IR @ VWM | <1 µA - ultra-low reverse leakage preserves system standby current in battery-powered applications |
| TJ max | +175 °C - extended junction temperature rating enables under-hood deployment without derating |
| Package | SOD-123W - industry-standard surface-mount outline with enhanced thermal pad and moisture level 1 (J-STD-020) |
Pinout & Package
SMF85AH uses the SOD-123W package: a compact, gull-wing leaded surface-mount outline with cathode band marking polarity. The device has two terminals: anode and cathode. Thermal performance is optimized via direct copper pad contact beneath the molded body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to ground or lower-potential rail in unidirectional TVS configuration |
| Cathode | Current exit point during clamping; marked by band | Connected to protected line (e.g., CAN_H, LIN, 12 V supply) - conducts when line exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD47 |
| Glass-passivated junction | Stable VBR over lifetime and temperature; prevents surface degradation under humidity and bias stress |
| ISO 7637-2 compliance | Withstands Pulse 1 (inductive flyback), Pulse 2a/2b (battery disconnect), and Pulse 3a/3b (EFT) without failure |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow - compatible with standard SMT assembly lines |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for green manufacturing |
Applications
| Automotive Body Control Module (BCM) | LED Headlamp Driver |
|---|---|
Use Scenario: Protection of LIN bus transceivers and power switches against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between LIN line and ground to clamp transients above 85 V while maintaining signal integrity. Use Value: Prevents latch-up or destruction of LIN transceivers during 12 V system surges up to +137 V clamped peak. | Use Scenario: Safeguarding constant-current LED driver ICs from inductive kickback during PWM dimming. IC Role / Device Role / Timing Role: TVS connected across high-side switch output to absorb energy from coil flyback. Use Value: Limits voltage overshoot to 137 V, avoiding MOSFET drain-source breakdown and ensuring >100,000-cycle reliability. |
| Industrial Sensor Interface | 12 V Power Rail Protection |
Use Scenario: Shielding analog front-end ICs (e.g., ADCs, op-amps) in factory automation sensors from EFT bursts. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) TVS on 3.3 V or 5 V supply rail to suppress sub-100 ns EFT pulses. Use Value: Maintains measurement accuracy by preventing transient-induced offset drift or digital latch-up. | Use Scenario: Guarding microcontroller power inputs in telematics units exposed to vehicle battery fluctuations. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main 12 V input, upstream of DC-DC converter. Use Value: Absorbs 200 W pulses without degradation, extending system uptime and reducing field return rates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85A | Same VWM (85 V), but lower PPPM (400 W), larger SMA package (RθJA = 110 °C/W), no AEC-Q101 qualification | General industrial use only; not suitable for automotive under-hood locations | Select SMAJ85A only if higher pulse power is needed and AEC-Q101 is not required |
| TPSMD8.5A | Lower VWM (8.5 V), different breakdown range (9.4–10.4 V), same SOD-123W footprint but non-automotive grade | Designed for 5–12 V logic-level protection, not 12 V/24 V power rail clamping | Not interchangeable - mismatched voltage rating makes TPSMD8.5A unsuitable for SMF85AH's 85 V application space |
Compared with SMAJ85A and TPSMD8.5A, the SMF85AH uniquely combines AEC-Q101 qualification, SOD-123W compactness, and precise 85 V standoff in a single automotive-grade TVS - making it the only drop-in solution for ISO 7637-2-compliant 12 V/24 V systems requiring zero layout change and full qualification traceability.
Availability
SMF85AH is available at Aetrix Electronics and suitable for automotive body control modules, LED lighting drivers, industrial sensor interfaces, and 12 V power rail protection requiring stable component supply across production lifecycles.
Supply support for SMF85AH 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, and rectifiers, with global distribution and AEC-Q101 validation capability.
The SMF series was developed specifically for automotive and industrial transient suppression, emphasizing high-reliability packaging, low leakage, and standardized SOD-123W compatibility across 5–100 V ratings.
FAQ
What is the clamping voltage of SMF85AH and how is it measured?
The SMF85AH has a maximum clamping voltage (VC) of 137 V, measured at a peak pulse current (IPPM) of 1.3 A using a 10/1000 µs waveform per IEC 61000-4-5. This value is guaranteed across temperature and ensures protected circuits experience no more than 137 V during transient events. The SMF85AH datasheet specifies this parameter under standard test conditions (TA = 25°C), and actual VC remains within ±5% over its full operating temperature range.
Is SMF85AH suitable for automotive applications?
Yes, SMF85AH is AEC-Q101 qualified and explicitly designed for automotive use. It meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements, supports junction temperatures up to +175 °C, and features glass-passivated junctions for long-term stability under thermal and humidity stress. These attributes make SMF85AH appropriate for under-hood and cabin modules where reliability is mission-critical.
What is the reverse leakage current of SMF85AH at its working voltage?
The SMF85AH exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its 85 V working stand-off voltage (VWM), tested at TA = 25°C. This ultra-low leakage minimizes quiescent power loss in always-on automotive subsystems such as telematics or alarm controllers, preserving battery life without compromising protection readiness.
Does SMF85AH have a defined polarity, and how is it marked?
Yes, SMF85AH is a unidirectional TVS diode with clearly defined polarity: the cathode is marked by a visible band on the SOD-123W package body. During circuit layout, the banded end must connect to the line being protected (e.g., 12 V rail or LIN bus), while the anode connects to ground. Incorrect orientation will prevent clamping and may cause catastrophic failure under overvoltage.
What is the thermal resistance of SMF85AH, and how does it affect PCB layout?
The SMF85AH has a junction-to-lead thermal resistance (RθJL) of 33 °C/W and junction-to-ambient (RθJA) of 100 °C/W when mounted on a 5 mm × 5 mm copper pad. To maintain TJ ≤ 175 °C under worst-case 200 W pulses, designers must provide adequate copper area and avoid thermal isolation. The SOD-123W footprint requires no special stencil adjustments but benefits from thermal vias under the pad for high-reliability automotive layouts.
SMF85AH 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):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 1.3A
- 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
SMF85AH FAQ
1.How can I place an order for SMF85AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF85AH 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 SMF85AH reliable?
The price and inventory of SMF85AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF85AH is usually 5 days.
3.What payment methods are accepted for SMF85AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF85AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF85AH?
SMF85AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF85AH 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 SMF85AH?
For technical support, including SMF85AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF85AH requirements.
6.How does Aetrix verify that SMF85AH is sourced from the original manufacturer or authorized distributors?
All SMF85AH 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 SMF85AH meets industry standards.
7.What is the process for return or replacement of SMF85AH?
All SMF85AH units undergo pre-shipment inspection (PSI). If there is an issue with SMF85AH, 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 SMF85AH part is unused and in its original packaging.
Return procedure for SMF85AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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