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onsemi 1SMA22AT3
- Part No.:
- 1SMA22AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA22AT3.pdf
- Description:
- TVS DIODE 22VWM 35.5VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,634
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Product details
Overview
1SMA22AT3 from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping high-energy transients in DC power rails and signal lines. It features a 22 V working peak reverse voltage (VRWM), 25.65 V nominal breakdown voltage (VBR) at 1 mA test current, 35.5 A maximum peak pulse current (IPP), and clamps to 35.5 V at that current. It is used in automotive power supply protection and industrial control I/O interfaces.
For engineers reviewing the 1SMA22AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin over operating voltage, clamping voltage vs. protected device's absolute maximum rating, surge current capability under 10/1000 µs waveform, and SMA package thermal performance on FR-4 PCBs.
Technical Context
The 1SMA22AT3 operates as a unidirectional avalanche diode, conducting only during negative transients relative to its anode–cathode orientation. Its clamping action begins at VRWM = 22 V and fully engages at VBR = 24.4–26.9 V (min–max), with VC = 35.5 V at IPP = 35.5 A under standardized 10/1000 µs surge conditions.
It exhibits <1 ns response time, 2.5 µA max reverse leakage at VRWM, and ESD robustness >16 kV per Human Body Model. Thermal design relies on junction-to-lead resistance of 20 °C/W and 1.5 W DC power dissipation at TL = 75 °C, requiring minimum copper pad area per Case 403D-02 footprint.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 22 V - Maximum continuous reverse voltage before significant leakage; sets minimum standoff for 24 V nominal systems. |
| VBR @ IT=1 mA | 24.4–26.9 V - Breakdown range defining turn-on threshold; ensures reliable conduction before downstream IC damage. |
| VC @ IPP=35.5 A | 35.5 V - Clamping voltage under full 400 W surge; must be below protected circuit's absolute max rating. |
| PPK | 400 W @ 1 ms - Peak surge power handling per single non-repetitive 10/1000 µs pulse. |
| IR @ VRWM | 2.5 µA max - Low leakage preserves efficiency in always-on bias networks and high-impedance sensing paths. |
| Response Time | <1 ns - Enables suppression of fast EFT/burst transients before logic or analog circuitry responds. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets IEC 61000-4-2 Level 4 system-level ESD immunity requirements. |
Pinout & Package
SMA package (Case 403D-02), surface-mount, low-profile plastic housing with molded cathode band polarity indicator. Dimensions: 4.06 × 2.29 × 1.91 mm (L × W × H). Mountable in top-slide or bottom-board orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry during forward conduction; tied to lower-potential node (e.g., GND or return rail) | Enables bidirectional protection when paired with another TVS; defines reference for unidirectional clamping direction. |
| Cathode | Current exit during reverse-biased clamping; connected to protected line (e.g., 24 V supply or signal) | Clamps positive transients to cathode potential; polarity band must align with PCB silkscreen to prevent misapplication. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Supports IEC 61000-4-5 Level 3 (1 kV/2 Ω) surge testing on 24 V industrial buses without derating. |
| Low zener impedance | Minimizes voltage overshoot during multi-pulse events; maintains stable clamping across temperature (-65°C to +150°C). |
| Pb-free (1SMA22AT3G) option | Complies with RoHS Directive 2011/65/EU; compatible with standard SnPb and lead-free reflow profiles (260°C/10 s). |
| Flat handling surface | Ensures consistent pick-and-place accuracy in automated SMT assembly; reduces tombstoning risk on 0805-equivalent footprint. |
| Void-free transfer-molded case | Prevents moisture ingress and thermal delamination under repeated surge stress; qualified per JESD22-A108. |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital Input Protection |
|---|---|
Use Scenario: Suppresses load dump spikes (up to 40 V, 100 ms) and ISO 7637-2 pulse 5a on 24 V battery-fed ECUs. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed between battery rail and DC-DC input stage. Use Value: Limits voltage excursion to ≤35.5 V, protecting 40 V-rated buck controllers and reducing need for oversized input capacitors. |
Use Scenario: Shields 24 V sinking digital inputs against field-wiring induced surges and relay coil flyback. IC Role / Device Role / Timing Role: Front-end transient suppressor ahead of optocoupler or Schmitt trigger input buffer. Use Value: Prevents false triggering and latch-up by clamping transients faster than microcontroller GPIO response time (<1 ns vs. ~100 ns). |
| Medical Equipment AC/DC Adapter Interface | Telecom Line Card Surge Protection |
Use Scenario: Guards secondary-side 24 V outputs of isolated medical-grade AC/DC adapters against conducted surges per IEC 60601-1 Ed.3. IC Role / Device Role / Timing Role: Secondary-side TVS on output rail, coordinated with primary-side MOV and Y-cap filtering. Use Value: Adds <1 ns response layer complementary to slower bulk components; meets 2× MOPP creepage/clearance safety spacing via compact SMA footprint. |
Use Scenario: Protects Ethernet PHY power pins and RS-485 transceiver VCC against lightning-induced surges on outdoor telecom cabinets. IC Role / Device Role / Timing Role: Localized clamping device mounted adjacent to connector or IC power pin. Use Value: Delivers 35.5 A surge current capacity within 3.5 mm² board area-enabling dense port count without sacrificing per-port protection margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ22A | Same VRWM (22 V), higher PPK = 600 W, larger SMB package (5.3 × 4.6 mm vs. SMA 4.1 × 2.3 mm) | Better surge margin but requires 2.3× more board area; suited for high-reliability telecom where space is secondary to energy rating. | Select SMBJ22A when 600 W surge headroom is required and PCB layout allows larger footprint. |
| 1.5SMC22A | Same VRWM (22 V), identical PPK = 400 W, but DO-214AB (SMC) package (7.1 × 6.2 mm) with higher thermal mass | Superior steady-state power handling (5 W vs. 0.5 W at TA=25°C); preferred for repetitive surge environments like motor drives. | Choose 1.5SMC22A for applications with frequent surge events (>1/min) where junction temperature rise must be minimized. |
Compared with SMBJ22A and 1.5SMC22A, the 1SMA22AT3 offers optimal balance of 400 W surge capability, ultra-fast response, and minimal 4.1 × 2.3 mm footprint-making it ideal for space-constrained 24 V industrial and automotive modules where single-event robustness is prioritized over repetitive duty or extreme energy absorption.
Availability
1SMA22AT3 is available at Aetrix Electronics and suitable for automotive body control modules, industrial programmable logic controller (PLC) inputs, and medical power supply secondary-side protection requiring stable component supply and long-term lifecycle support.
Supply support for 1SMA22AT3 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
ON Semiconductor (now onsemi) is a global semiconductor supplier specializing in power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud power applications.
The 1SMA22AT3 belongs to the SMA-series unidirectional TVS family engineered specifically for cost-sensitive, high-volume board-level transient suppression in 12–78 V DC systems-emphasizing fast response, repeatable clamping, and compatibility with automated SMT assembly.
FAQ
What is the maximum clamping voltage of the 1SMA22AT3 under surge conditions?
The 1SMA22AT3 clamps to 35.5 V when subjected to its rated peak pulse current of 35.5 A, measured using the standardized 10/1000 µs waveform. This value is guaranteed across temperature and represents the upper limit of voltage seen by downstream circuitry during a full 400 W transient event. The 1SMA22AT3 datasheet specifies this as VC, and it is validated per JEDEC standards.
Is the 1SMA22AT3 suitable for bidirectional transient suppression?
No, the 1SMA22AT3 is strictly unidirectional and conducts only during reverse-bias transients. For bidirectional protection, ON Semiconductor offers the 1SMA22CAT3 variant (with 'C' suffix), which provides symmetrical clamping for both polarities. Using the 1SMA22AT3 in bidirectional applications risks failure during positive-going transients on the anode side.
What is the thermal resistance and power derating behavior of the 1SMA22AT3?
The 1SMA22AT3 has a junction-to-lead thermal resistance (RJL) of 20 °C/W and delivers 1.5 W DC power dissipation at TL = 75 °C. Above 75 °C, it derates linearly at 20 mW/°C. On a standard FR-4 board with ON Semiconductor's recommended footprint, its junction-to-ambient resistance is 250 °C/W, limiting ambient-rated DC power to 0.5 W at 25 °C.
Does the 1SMA22AT3 meet RoHS and lead-free assembly requirements?
Yes-the 1SMA22AT3G variant is the Pb-free version, qualified to RoHS Directive 2011/65/EU and compatible with standard lead-free reflow profiles (peak 260 °C for 10 seconds). The base 1SMA22AT3 is SnPb-terminated; both share identical electrical specs and SMA package dimensions.
How does the 1SMA22AT3 compare to the 1N6267A in terms of surge capability and package?
The 1SMA22AT3 delivers identical 400 W peak power and 22 V VRWM as the through-hole 1N6267A but uses a surface-mount SMA package (4.1 × 2.3 mm) instead of DO-41 (5.2 × 2.7 mm). This enables higher assembly density and eliminates wave soldering steps. Both share the same VBR range and clamping voltage, but the 1SMA22AT3 offers superior automated placement yield due to its flat handling surface.
1SMA22AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 11.3A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 540pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA22AT3 FAQ
1.How can I place an order for 1SMA22AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA22AT3 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 1SMA22AT3 reliable?
The price and inventory of 1SMA22AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA22AT3 is usually 5 days.
3.What payment methods are accepted for 1SMA22AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA22AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA22AT3?
1SMA22AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA22AT3 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 1SMA22AT3?
For technical support, including 1SMA22AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA22AT3 requirements.
6.How does Aetrix verify that 1SMA22AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA22AT3 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 1SMA22AT3 meets industry standards.
7.What is the process for return or replacement of 1SMA22AT3?
All 1SMA22AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA22AT3, 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 1SMA22AT3 part is unused and in its original packaging.
Return procedure for 1SMA22AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA22AT3 Tags
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