My Inquiry
My Account
Taiwan Semiconductor Corporation SMF33A
- Part No.:
- SMF33A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF33A.pdf
- Description:
- TVS DIODE 33VWM 53.3VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:19,900
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF33A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy ESD and surge protection in power and signal lines. It features a 33 V working stand-off voltage (VWM), 36.7–40.6 V breakdown voltage (VBR), 53.3 V clamping voltage (VC) at 3.8 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It is commonly used in automotive lighting control modules and industrial I/O protection circuits.
For engineers reviewing the SMF33A datasheet, SMF33A pinout, SMF33A application, or SMF33A equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, SOD-123W package thermal resistance (RθJL = 33 °C/W), low leakage (<1 µA @ 33 V), and compliance with JESD201 Class 2 whisker testing.
Technical Context
The SMF33A operates as a unidirectional avalanche diode, activated when reverse voltage exceeds its breakdown threshold (VBR min = 36.7 V). Its clamping action limits transient-induced voltage to ≤53.3 V at 3.8 A, protecting downstream ICs such as microcontrollers and CAN transceivers.
It meets ISO 7637-2 immunity requirements for automotive electronics and is rated for junction temperatures from –55 °C to +175 °C. The SOD-123W package provides robust thermal performance (RθJA = 100 °C/W on 5 mm × 5 mm Cu pad) and supports automated placement with matte tin-plated leads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 33 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR (min/max) | 36.7 V / 40.6 V - Breakdown occurs within this range at 1 mA test current; defines turn-on threshold tolerance |
| VC @ IPPM | 53.3 V @ 3.8 A - Clamped voltage during 10/1000 µs surge; determines maximum stress on protected circuit |
| PPPM | 200 W - Peak pulse power handling capability; validates suitability for ISO 7637-2 Pulse 3b (inductive load dump) |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; ensures minimal standby power loss in battery-powered systems |
| Junction Temp | –55 °C to +175 °C - Enables deployment in under-hood automotive or industrial motor drive environments |
| RθJL | 33 °C/W - Low junction-to-lead thermal resistance supports reliable power dissipation without external heatsinking |
Pinout & Package
Package: SOD-123W - Surface-mount plastic package with cathode band marking, UL 94V-0 molding compound, and matte tin-plated leads compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., ground or return path) in unidirectional TVS configuration |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 33 V supply rail); clamps transients toward anode when voltage exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| Photo glass passivated junction | Enhances long-term reliability and stability of VBR under thermal cycling and humidity exposure |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validated for automotive load-dump and inductive switching surge immunity without external filtering |
| Moisture sensitivity level 1 | Enables standard SMT reflow without baking or special handling per J-STD-020 |
| Halogen-free construction | Meets IEC 61249-2-21 for environmentally restricted applications and RoHS-compliant manufacturing |
| Low clamping ratio (VC/VBR ≈ 1.37) | Minimizes overvoltage margin between clamping and breakdown, improving protection headroom |
Applications
| Automotive Lighting Control | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting LED driver ICs and MOSFET gate drivers from load-dump surges in 24 V vehicle lighting systems. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and ground to clamp transients before they reach sensitive logic. Use Value: Limits peak voltage to 53.3 V during 200 W pulses, preventing latch-up or gate oxide damage in 33 V-rated drivers. | Use Scenario: Shielding 24 V digital input channels in programmable logic controllers from field-wiring induced EFT bursts. IC Role / Device Role / Timing Role: Standoff protection device on input line, absorbing fast transients while maintaining <1 µA leakage during normal operation. Use Value: Ensures signal integrity and prevents false triggering during IEC 61000-4-4 EFT testing up to ±2 kV. |
| Automotive Body Control Module | Smart Sensor Power Rail Protection |
Use Scenario: Safeguarding microcontroller I/O pins and LIN bus transceivers against battery reverse connection and jump-start spikes. IC Role / Device Role / Timing Role: Primary clamping element on 33 V auxiliary supply rail feeding BCM sub-circuits. Use Value: Withstands repetitive 10/1000 µs surges per ISO 7637-2 Pulse 2b, enabling robust field deployment. | Use Scenario: Protecting low-power MEMS sensors and ADC front-ends powered from regulated 3.3 V or 5 V rails derived from 33 V intermediate supplies. IC Role / Device Role / Timing Role: Secondary-stage TVS on DC-DC converter output, suppressing coupling from upstream transients. Use Value: Delivers <1 µA leakage and 53.3 V clamping to preserve sensor accuracy and avoid ADC saturation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33A (Bourns) | Same VWM (33 V), but SMB package (larger footprint, RθJA = 50 °C/W vs. 100 °C/W) | Better thermal dissipation; requires larger PCB area and may not fit space-constrained automotive modules | Select when higher steady-state power handling (>1 W) or improved thermal margin is required |
| P6SMB33A (Littelfuse) | Identical electrical specs (VWM, VBR, VC), same SOD-123W package, but moisture sensitivity level 2 (requires baking before reflow) | Requires additional process step in high-volume SMT lines; identical protection performance otherwise | Select when sourcing flexibility is prioritized and baking infrastructure is available |
Compared with SMBJ33A and P6SMB33A, the SMF33A offers superior board-space efficiency and simplified assembly (MSL-1), making it optimal for compact automotive ECUs and industrial edge nodes where layout density and process yield are critical.
Availability
SMF33A is available at Aetrix Electronics and suitable for automotive lighting control, industrial PLC digital inputs, and body control module designs requiring stable component supply and full ISO 7637-2 compliance.
Supply support for SMF33A 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 power MOSFETs.
The SMF series was developed specifically for high-reliability automotive and industrial transient suppression, emphasizing MSL-1 manufacturability, ISO 7637-2 compliance, and tight VBR tolerances in compact SOD-123W packaging.
FAQ
What is the clamping voltage of the SMF33A under a 10/1000 µs surge?
The SMF33A has a maximum clamping voltage (VC) of 53.3 V when subjected to a 10/1000 µs waveform at its rated peak pulse current of 3.8 A. This value is measured per JEDEC standards and ensures predictable overvoltage limiting for protected circuits. The SMF33A maintains this clamping performance across its specified junction temperature range (–55 °C to +175 °C), making it suitable for under-hood automotive use.
Is the SMF33A unidirectional or bidirectional?
The SMF33A is a unidirectional TVS diode, intended for DC line protection where polarity is fixed. Its datasheet specifies breakdown and clamping only in reverse bias, with forward voltage (VF) of 3.5 V at 12 A. Bidirectional variants (e.g., SMF33CA) are separate part numbers; the SMF33A must be oriented with cathode toward the protected line to function correctly.
Does the SMF33A meet automotive surge immunity standards?
Yes, the SMF33A meets ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a/2b (supply line transients), and Pulse 3a/3b (capacitive coupled noise), as explicitly stated in its official datasheet. Its 200 W peak pulse power rating and verified clamping behavior make it suitable for AEC-Q101-qualified systems when used within derated conditions.
What is the moisture sensitivity level (MSL) of the SMF33A?
The SMF33A has a moisture sensitivity level of MSL-1 per J-STD-020, meaning it can be stored indefinitely at ambient conditions and processed using standard reflow profiles without pre-baking. This eliminates moisture-related popcorning risk and simplifies high-volume SMT manufacturing-unlike alternatives such as P6SMB33A, which require MSL-2 handling.
Can the SMF33A replace the SMBJ33A in existing designs?
The SMF33A is not a direct drop-in replacement for the SMBJ33A due to differing packages: SMF33A uses SOD-123W (smaller footprint), while SMBJ33A uses SMB (larger, higher thermal mass). Although both share identical VWM (33 V) and comparable clamping, PCB layout revision is required. Thermal performance also differs-SMF33A has higher RθJA (100 °C/W vs. 50 °C/W)-so power derating must be re-evaluated.
SMF33A 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):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 3.8A
- 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
SMF33A FAQ
1.How can I place an order for SMF33A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF33A 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 SMF33A reliable?
The price and inventory of SMF33A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF33A is usually 5 days.
3.What payment methods are accepted for SMF33A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF33A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF33A?
SMF33A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF33A 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 SMF33A?
For technical support, including SMF33A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF33A requirements.
6.How does Aetrix verify that SMF33A is sourced from the original manufacturer or authorized distributors?
All SMF33A 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 SMF33A meets industry standards.
7.What is the process for return or replacement of SMF33A?
All SMF33A units undergo pre-shipment inspection (PSI). If there is an issue with SMF33A, 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 SMF33A part is unused and in its original packaging.
Return procedure for SMF33A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF33A 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
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
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…
