My Inquiry
My Account
Taiwan Semiconductor Corporation SMF22A
- Part No.:
- SMF22A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF22A.pdf
- Description:
- TVS DIODE 22VWM 35.5VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:19,850
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF22A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy ESD and surge protection in DC power rails and signal lines. It features a 22 V working stand-off voltage (VWM), 24.4–26.9 V breakdown voltage (VBR), 35.5 V clamping voltage (VC) at 5.6 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It is commonly deployed in automotive body electronics and industrial I/O protection.
For engineers reviewing the SMF22A datasheet, SMF22A pinout, SMF22A application, or SMF22A equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, low leakage (<1 µA @ 22 V), SOD-123W package compatibility with automated placement, and thermal resistance (RθJL = 33 °C/W) for PCB-level power dissipation management.
Technical Context
The SMF22A 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 its SOD-123W package enables high thermal transfer via lead-to-board conduction.
It is rated for 175 °C maximum junction temperature and meets JESD201 Class 2 whisker resistance and J-STD-020 Moisture Sensitivity Level 1. The device sustains 200 W peak pulse power per 10/1000 µs waveform (derated above 25 °C ambient), with clamping voltage tightly controlled at 35.5 V under 5.6 A IPPM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 22 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 24.4 V / 26.9 V - Breakdown occurs within this range at 1 mA test current, defining turn-on threshold |
| VC @ IPPM | 35.5 V - Clamped voltage seen by protected circuit during 5.6 A 10/1000 µs surge |
| PPPM | 200 W - Peak transient power it can absorb without failure (10/1000 µs waveform) |
| IR @ VWM | <1 µA - Reverse leakage at 22 V ensures minimal standby power loss in always-on systems |
| RθJL | 33 °C/W - Junction-to-lead thermal resistance enables effective heat transfer to PCB copper pads |
| TJ max | 175 °C - Maximum junction temperature supports operation in under-hood automotive environments |
Pinout & Package
Package: SOD-123W - Surface-mount plastic package with matte tin-plated leads, UL 94V-0 molding compound, cathode band polarity indicator, and 0.016 g mass. Designed for reflow soldering per J-STD-002.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., ground or return path) in unidirectional configuration |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 24 V rail or CAN_H); conducts when transient exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance (±5%), low IR drift over temperature, and long-term reliability in harsh environments |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) immunity testing |
| Low clamping ratio (VC/VBR ≈ 1.37) | Minimizes overvoltage stress on downstream ICs-e.g., protects 3.3 V or 5 V logic interfaces even when placed on 24 V supply lines |
| SOD-123W mechanical robustness | Withstands JESD201 Class 2 whisker growth and supports automated pick-and-place with <0.016 g mass and defined tape/reel packaging (10,000 pcs/reel) |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally regulated industrial and automotive production |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting microcontroller GPIOs and LIN bus transceivers from load-dump surges and ESD events in door module ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between 12 V supply rail and ground, triggered only during negative transients exceeding 24.4 V. Use Value: Limits clamped voltage to 35.5 V, well below typical 40 V absolute maximum ratings of automotive-grade MCUs and LIN transceivers. | Use Scenario: Safeguarding 24 V digital input channels against field-wiring induced surges and contact bounce in factory automation cabinets. IC Role / Device Role / Timing Role: Standoff protector on the input side of optocoupler-based isolation stages, absorbing fast transients before signal conditioning. Use Value: Sub-1 µA leakage at 22 V prevents false triggering in high-impedance sensing circuits; 200 W pulse rating handles repetitive switching noise. |
| LED Driver Power Supply | RS-485 Transceiver Interface |
Use Scenario: Suppressing inductive kickback from relay coils and solenoid drivers powering outdoor LED signage. IC Role / Device Role / Timing Role: Parallel-connected TVS across relay coil terminals to clamp flyback voltage spikes during de-energization. Use Value: 35.5 V clamping prevents damage to MOSFET gate drivers and ensures reliable coil suppression without excessive voltage overshoot. | Use Scenario: Protecting RS-485 transceiver pins (A/B) from EFT bursts and lightning-induced surges in building control networks. IC Role / Device Role / Timing Role: Bidirectionally configured pair (two SMF22A back-to-back) or used with external series impedance to limit current into transceiver ESD structures. Use Value: Low capacitance (~100 pF at 1 MHz) avoids signal integrity degradation on 10 Mbps RS-485 buses while maintaining sub-36 V clamping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ22A (onsemi) | Same VWM (22 V), slightly higher VC (37.5 V @ 5.3 A), SMA package (larger footprint, RθJA = 110 °C/W) | Less suitable for space-constrained PCBs; higher thermal resistance limits sustained surge duty cycle | Prefer SMF22A where board area and thermal performance are critical; SMAJ22A acceptable if legacy SMA footprint exists |
| P6SMB22A (Littelfuse) | Identical VWM and VC specs, but SMB package (higher RθJA = 125 °C/W, 1.5× larger than SOD-123W) | Lower power density; requires larger copper pour for equivalent thermal management | SMF22A offers superior board-area efficiency and thermal response-choose when miniaturization or high-reliability automotive layout is required |
Compared with SMAJ22A and P6SMB22A, the SMF22A delivers identical electrical protection performance in a significantly smaller SOD-123W package with better thermal conduction (RθJL = 33 °C/W), enabling tighter layouts and improved surge endurance in thermally constrained designs.
Availability
SMF22A is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, LED driver protection, and RS-485 interface hardening requiring stable component supply and consistent parametric performance across production lots.
Supply support for SMF22A 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 power management devices.
The SMF22A belongs to TSC's SMF-series unidirectional TVS family, engineered specifically for high-reliability, high-surge immunity in automotive and industrial environments where compact size, low leakage, and ISO 7637-2 compliance are mandatory.
FAQ
What is the maximum clamping voltage of the SMF22A under standard test conditions?
The SMF22A has a maximum clamping voltage (VC) of 35.5 V when subjected to a 10/1000 µs surge waveform with a peak current (IPPM) of 5.6 A. This value is measured at TA = 25 °C and defines the upper voltage limit imposed on protected circuitry during transient events. The SMF22A maintains this clamping performance consistently across its specified operating temperature range, making it suitable for use in environments where voltage-sensitive components must be shielded from overvoltage stress.
Does the SMF22A meet automotive surge immunity standards?
Yes, the SMF22A meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling). Its 200 W peak pulse power rating, low clamping voltage, and stable VBR tolerance ensure robust protection in automotive body electronics such as BCMs and lighting control units. The SMF22A is not qualified to AEC-Q200, but its design and test validation align with common automotive system-level surge immunity needs.
What is the reverse leakage current specification for the SMF22A at its working voltage?
The SMF22A exhibits a maximum reverse leakage current (IR) of less than 1 µA when biased at its 22 V working stand-off voltage (VWM) and tested at TA = 25 °C. This ultra-low leakage ensures minimal power loss in always-on systems and prevents false triggering in high-impedance sensing circuits. The SMF22A maintains this performance across its full operating temperature range, supporting reliable operation in battery-powered and energy-sensitive applications.
Can the SMF22A be used for bidirectional transient protection?
No-the SMF22A is a unidirectional TVS diode and conducts only in reverse bias above its breakdown voltage. For bidirectional protection (e.g., AC lines or differential buses like RS-485), two SMF22A devices must be connected in series opposition (anode-to-anode), or a dedicated bidirectional part such as SMBJ22CA should be selected. Using a single SMF22A in forward bias provides no clamping action and may conduct destructively if forward voltage exceeds 3.5 V at 12 A.
What is the thermal resistance from junction to lead (RθJL) for the SMF22A?
The SMF22A has a typical junction-to-lead thermal resistance (RθJL) of 33 °C/W when mounted on a standard 5 mm × 5 mm copper pad PCB per JEDEC test conditions. This low value enables efficient heat transfer from the die to the PCB, supporting higher surge repetition rates and extended reliability in thermally demanding applications. The SMF22A's SOD-123W package contributes directly to this performance, distinguishing it from larger-package alternatives like SMA or SMB.
SMF22A 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):
- 22V
- Voltage - Breakdown (Min):
- 24.4V
- Voltage - Clamping (Max) @ Ipp:
- 35.5V
- Current - Peak Pulse (10/1000µs):
- 5.6A
- 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
SMF22A FAQ
1.How can I place an order for SMF22A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF22A 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 SMF22A reliable?
The price and inventory of SMF22A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF22A is usually 5 days.
3.What payment methods are accepted for SMF22A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF22A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF22A?
SMF22A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF22A 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 SMF22A?
For technical support, including SMF22A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF22A requirements.
6.How does Aetrix verify that SMF22A is sourced from the original manufacturer or authorized distributors?
All SMF22A 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 SMF22A meets industry standards.
7.What is the process for return or replacement of SMF22A?
All SMF22A units undergo pre-shipment inspection (PSI). If there is an issue with SMF22A, 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 SMF22A part is unused and in its original packaging.
Return procedure for SMF22A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF22A 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…
