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STMicroelectronics SM6T22A
- Part No.:
- SM6T22A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T22A.pdf
- Description:
- TVS DIODE 18.8VWM 30.6VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:9,178
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Product details
Overview
SM6T22A from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode in SMB package, designed for IEC 61000-4-2 ESD and IEC 61000-4-4 surge protection of signal lines and ICs. It features a 22 V nominal breakdown voltage (VBR = 20.9–23.1 V), 30.6 V clamping voltage at 1 A (10/1000 µs), 600 W peak pulse power, and low leakage current (0.2 µA at 25 °C). It is used in industrial sensor interfaces and power supply input stages to safeguard MOSFETs and microcontrollers.
For engineers reviewing the SM6T22A datasheet, SM6T22A pinout, SM6T22A application, or SM6T22A equivalent, this page delivers verified electrical parameters, SMB package layout, real-world clamping behavior under 10/1000 µs transients, thermal derating curves up to 150 °C junction temperature, and validated alternatives for ESD-hardened designs.
Technical Context
The SM6T22A operates as a silicon avalanche diode with planar junction technology, enabling stable VBR drift coefficient (αT = 9.2 × 10−4/°C) and high-temperature reliability up to Tj = 150 °C. Its unidirectional configuration provides forward conduction only during positive transients, with reverse standoff voltage (VRWM) of 18.8 V and maximum reverse leakage of 0.2 µA at 25 °C.
Clamping performance is defined by dynamic resistance RD = 0.375 Ω (10/1000 µs) and VCL = 30.6 V at IPP = 1 A, ensuring predictable voltage limiting during fast transients. Compliance with UL497B (file E136224), IEC 61000-4-2 (±30 kV contact/air), and IEC 61000-4-4 level 4 (4 kV) confirms suitability for isolated loop circuit protection in industrial control systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 20.9 / 22.0 / 23.1 V - ensures reliable avalanche initiation above 20.9 V while maintaining tight tolerance for consistent protection threshold |
| VRWM | 18.8 V - maximum continuous reverse operating voltage before significant leakage begins |
| VCL @ 1 A (10/1000 µs) | 30.6 V - clamped voltage seen by protected circuit during 1 A surge, defining worst-case overvoltage stress |
| PPP (10/1000 µs) | 600 W - peak transient power dissipation capability at 25 °C ambient, derates to 350 W at Tj = 150 °C |
| IR @ VRWM | 0.2 µA at 25 °C - ultra-low leakage preserves signal integrity in high-impedance sensor inputs |
| RD (dynamic) | 0.375 Ω - low incremental resistance enables sharp voltage clamping and minimal overshoot during fast transients |
| Tj max | 150 °C - enables operation in enclosed industrial enclosures without forced cooling |
Pinout & Package
The SM6T22A is housed in an SMB (DO-214AA) surface-mount package with two terminals: cathode (marked end) and anode. The package measures 3.30–3.95 mm (D) × 5.10–5.60 mm (E) × 1.90–2.45 mm (A1) and uses matte tin-plated leads compliant with J-STD-002 and JEDEC standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Transient current sink | Connected to protected line; conducts avalanche current to ground during overvoltage events |
| Anode | Reference node | Typically tied to system ground or lower-potential rail; completes clamping path during reverse-biased surges |
Key Features
| Feature | Design Value |
|---|---|
| UL497B recognition | Approved as isolated loop circuit protector (file E136224), enabling use in safety-critical telecom and industrial isolation barriers |
| Low-temperature coefficient | αT = 9.2 × 10−4/°C - ensures <1% VBR shift across −55 to +150 °C operating range |
| High-temperature power rating | 350 W (10/1000 µs) at Tj = 150 °C - supports sustained surge immunity in thermally constrained SMPS designs |
| ESD robustness | ±30 kV contact/air per IEC 61000-4-2 - exceeds level 4, eliminating need for external ESD staging in front-end interfaces |
| Planar junction construction | Enables low leakage (<1 µA up to 85 °C) and stable long-term parametric drift in high-reliability applications |
Applications
| Industrial Sensor Interface | DC Power Input Protection |
|---|---|
Use Scenario: Protecting 4–20 mA current-loop transmitters against induced lightning surges on field wiring. IC Role / Device Role / Timing Role: Unidirectional TVS placed between signal line and ground to clamp transients before they reach analog front-end op-amps or ADCs. Use Value: Limits voltage to ≤30.6 V during 1 A surge, preventing latch-up or gate oxide damage in precision instrumentation amplifiers. | Use Scenario: Safeguarding 24 V DC input rails of PLC I/O modules exposed to inductive switching noise. IC Role / Device Role / Timing Role: Primary surge suppressor on main power entry, coordinated with upstream fuse and downstream LC filtering. Use Value: Absorbs 600 W (10/1000 µs) transients without degradation, maintaining system uptime in factory automation environments. |
| Motor Drive Gate Driver Protection | Automotive Body Control Module (BCM) |
Use Scenario: Shielding high-side MOSFET gate drivers from Miller-induced voltage spikes during PWM switching. IC Role / Device Role / Timing Role: Fast-clamping TVS placed between gate and source to suppress dv/dt-induced ringing exceeding VGS rating. Use Value: Sub-1 ns response time and 0.375 Ω RD limit gate overvoltage to <31 V, avoiding unintended turn-on or dielectric failure. | Use Scenario: ESD protection for LIN bus transceivers in door module electronics subjected to human-body-model discharges. IC Role / Device Role / Timing Role: Unidirectional TVS on LIN data line, referenced to vehicle ground, meeting ISO 10605 requirements. Use Value: Withstands ±30 kV air discharge per IEC 61000-4-2, eliminating field failures due to assembly-line ESD events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ22A | Same SMB package, but higher PPP = 600 W (10/1000 µs) and VCL = 33.2 V at 1 A; slightly higher RD = 0.444 Ω | Marginally higher clamping voltage reduces protection margin for 3.3 V logic interfaces | Select when higher surge margin is needed and 2.6 V higher VCL is acceptable in 24 V systems |
| P6SMB22A | Identical VBR (20.9–23.1 V) and VCL (30.6 V), but rated for 600 W at 25 °C only; no UL497B listing | Lacks UL497B certification, limiting use in safety-isolated circuits requiring recognized protectors | Prefer for cost-sensitive non-safety applications where certification is not mandated |
Compared with SMBJ22A and P6SMB22A, the SM6T22A offers tighter VBR tolerance, UL497B recognition for isolated loop compliance, and superior high-temperature power retention-making it optimal for industrial control systems requiring certified, thermally robust surge protection.
Availability
SM6T22A is available at Aetrix Electronics and suitable for industrial sensor interfaces, DC power input protection, motor drive gate driver protection, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SM6T22A 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensing solutions for industrial, automotive, and consumer markets.
The SM6T series belongs to ST's transient protection portfolio, engineered specifically for high-reliability ESD and surge suppression in harsh industrial environments where low leakage, thermal stability, and regulatory compliance are mandatory.
FAQ
What is the maximum clamping voltage of SM6T22A under a 10/1000 µs 1 A surge?
The SM6T22A clamps to 30.6 V at 1 A for a 10/1000 µs waveform, as specified in Table 2 of DS0684 Rev 15. This value is measured at Tamb = 25 °C and defines the upper voltage bound imposed on protected circuitry during standardized surge events.
Does SM6T22A meet IEC 61000-4-2 level 4 ESD requirements?
Yes - the SM6T22A exceeds IEC 61000-4-2 level 4, withstanding ±30 kV contact and ±30 kV air discharge per the datasheet. Its planar junction structure and low capacitance ensure fast response without degrading signal integrity in high-speed interfaces.
Can SM6T22A be used in bidirectional configurations?
No - SM6T22A is unidirectional. For bidirectional protection, ST offers the SM6T22CA variant, which has symmetrical clamping in both polarities and identical VBR and VCL ratings in either direction.
What is the thermal resistance junction-to-ambient for SM6T22A on a standard FR4 PCB?
On a recommended footprint (Figure 14) with 70 µm copper thickness, the SM6T22A exhibits Rth(j-a) ≈ 120 °C/W for a 1 cm² copper area per lead, dropping to ~60 °C/W with 4.5 cm² total copper. This enables effective heat dissipation during repetitive surge events up to 150 °C junction temperature.
SM6T22A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6T, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18.8V
- Voltage - Breakdown (Min):
- 20.9V
- Voltage - Clamping (Max) @ Ipp:
- 30.6V
- Current - Peak Pulse (10/1000µs):
- 20A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T22A FAQ
1.How can I place an order for SM6T22A through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T22A 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 SM6T22A reliable?
The price and inventory of SM6T22A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T22A is usually 5 days.
3.What payment methods are accepted for SM6T22A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T22A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T22A?
SM6T22A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T22A 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 SM6T22A?
For technical support, including SM6T22A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T22A requirements.
6.How does Aetrix verify that SM6T22A is sourced from the original manufacturer or authorized distributors?
All SM6T22A 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 SM6T22A meets industry standards.
7.What is the process for return or replacement of SM6T22A?
All SM6T22A units undergo pre-shipment inspection (PSI). If there is an issue with SM6T22A, 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 SM6T22A part is unused and in its original packaging.
Return procedure for SM6T22A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T22A Tags
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