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onsemi 1SMA12AT3H
- Part No.:
- 1SMA12AT3H
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMA12AT3H.pdf
- Description:
- TRANS VOLTAGE SUPPRESSOR DIODE
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
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Product details
Overview
1SMA12AT3H from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed to protect sensitive electronics against ESD and surge events. It features a 12 V working peak reverse voltage (VRWM), 14.0 V nominal breakdown voltage (VBR), 19.9 V clamping voltage (VC) at 20.1 A peak pulse current (IPP), and <1 ns response time - deployed in power supplies, automotive ECUs, and industrial control interfaces.
For engineers reviewing the 1SMA12AT3H datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system DC bus voltage, VC margin relative to IC absolute maximum ratings, thermal derating above 75°C, and SMA package compatibility with automated SMT placement and reflow profiles.
Technical Context
This device operates as a unidirectional clamping TVS diode, conducting only during reverse overvoltage transients while remaining high-impedance under normal bias. Its low zener impedance and fast sub-nanosecond response enable effective suppression of ESD (Class 3, >16 kV HBM) and 10/1000 µs surge waveforms up to 400 W.
The 1SMA12AT3H uses a planar junction structure in an SMA (DO-214AC) surface-mount package with cathode band marking. Thermal performance is defined for zero-lead-length mounting on FR-4 PCBs, with 50°C/W junction-to-lead and 250°C/W junction-to-ambient resistance - requiring careful layout for sustained surge handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Power Dissipation | 400 W @ 1 ms, 10/1000 µs waveform - defines maximum single-event surge energy absorption capability |
| Working Peak Reverse Voltage (VRWM) | 12 V - must be ≥ continuous operating voltage of protected circuit to avoid leakage or conduction during normal operation |
| Breakdown Voltage (VBR) | 13.3–14.7 V @ 1 mA test current - ensures reliable turn-on within specified tolerance before clamping begins |
| Clamping Voltage (VC) | 19.9 V @ 20.1 A IPP - maximum voltage seen by downstream components during worst-case surge event |
| Junction Capacitance | 925 pF @ 0 V, 1 MHz - impacts high-frequency signal integrity; relevant for data line protection near USB or CAN interfaces |
| ESD Rating | Class 3 (>16 kV HBM) - meets IEC 61000-4-2 Level 4 for robust board-level ESD immunity |
| Response Time | <1 ns - enables suppression before transient propagates into IC input structures |
Pinout & Package
The 1SMA12AT3H is housed in an SMA (DO-214AC) surface-mount package per CASE 403D, featuring a flat handling surface, low profile (max height 2.20 mm), and polarity indicated by a molded cathode band. Mounting position is unrestricted; soldering temperature limit is 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked side) | Transient current sink node | Connected to protected line; conducts surge current to ground when reverse voltage exceeds VRWM |
| Anode | Reference / return path | Typically tied to system ground or low-impedance return plane; completes clamping current path |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power rating | Enables protection against IEC 61000-4-5 Level 3 (1 kV/2 Ω) surges without derating in compact layouts |
| Low clamping ratio (VC/VBR ≈ 1.42) | Minimizes overvoltage stress on downstream ICs compared to higher-ratio TVS devices |
| Pb-free SURMETIC® package | Meets RoHS and JEDEC J-STD-020 reflow requirements; compatible with standard SnPb and lead-free assembly |
| Flat handling surface | Ensures consistent pick-and-place accuracy and coplanarity during automated SMT assembly |
| AEC-Q101 qualified (SZ-prefix variant) | Validated for automotive underhood applications; 1SMA12AT3H shares identical electrical specs and package |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) I/O Lines |
|---|---|
Use Scenario: 24 V DC input rail exposed to load dump and ISO 7637-2 pulses in programmable logic controllers. IC Role / Device Role / Timing Role: Unidirectional TVS clamping element placed between input terminal and ground plane. Use Value: Limits transient voltage to ≤19.9 V during 20.1 A surges, preventing damage to upstream DC-DC controller ICs rated for 20 V absolute max. |
Use Scenario: LIN bus transceiver pins subjected to ESD events and battery disconnect transients in door module ECUs. IC Role / Device Role / Timing Role: Line-side transient suppressor mounted directly at connector entry point. Use Value: Clamps 15 kV HBM ESD strikes within <1 ns, maintaining LIN signal integrity and avoiding transceiver latch-up or permanent failure. |
| Medical Equipment AC-DC Adapter Interface | Industrial PLC Digital Input Card Protection |
Use Scenario: Secondary-side 12 V DC output of medical-grade AC-DC adapter connected to patient-monitoring sensor interface. IC Role / Device Role / Timing Role: Final-stage overvoltage guard before analog front-end ASIC inputs. Use Value: Provides Class 3 ESD immunity and 400 W surge margin without adding series resistance that would degrade low-noise signal conditioning. |
Use Scenario: 24 V digital input channel on modular PLC receiving signals from external proximity sensors and switches. IC Role / Device Role / Timing Role: Primary transient barrier at field-wire entry point on input terminal block. Use Value: Absorbs repetitive 10/1000 µs surges up to 400 W without degradation, ensuring long-term reliability in factory-floor electromagnetic environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ12A | Higher 600 W peak power; larger SMB (DO-214AA) package; 20.1 V VC @ 29.8 A IPP | Better suited for higher-energy surges; requires larger PCB footprint and different stencil design | Select when system-level surge testing exceeds IEC 61000-4-5 Level 3 or when longer pulse durations apply |
| 1.5SMC12A | Same 400 W rating but in larger SMC (DO-214AB) package; 19.9 V VC @ 20.1 A IPP; higher thermal mass | Improved thermal dissipation for repetitive surge duty cycles; less suitable for space-constrained layouts | Prefer for industrial motor drives where multiple surges occur in quick succession and board area permits |
Compared with SMBJ12A and 1.5SMC12A, the 1SMA12AT3H offers optimal balance of surge robustness, compact SMA footprint, and cost-effective manufacturability - making it ideal for high-volume consumer, industrial, and automotive applications where board space and assembly efficiency are critical.
Availability
1SMA12AT3H is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and medical device interfaces requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for 1SMA12AT3H 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 is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud power applications.
The 1SMA12AT3H belongs to ON Semiconductor's SMA-series unidirectional TVS family, engineered for cost-sensitive, high-reliability transient suppression in space-constrained SMT designs across automotive, industrial, and medical end equipment.
FAQ
What is the maximum clamping voltage of the 1SMA12AT3H under surge conditions?
The 1SMA12AT3H has a maximum clamping voltage (VC) of 19.9 V when subjected to its rated peak pulse current of 20.1 A, measured using the standard 10/1000 µs waveform. This value is guaranteed across temperature and represents the highest voltage downstream components will experience during a worst-case transient event. The 1SMA12AT3H maintains this clamping performance with minimal variation due to its low zener impedance and stable junction characteristics.
Is the 1SMA12AT3H RoHS compliant and lead-free?
Yes, the 1SMA12AT3H is a Pb-free device manufactured in ON Semiconductor's SURMETIC® package and complies with RoHS Directive 2011/65/EU. It is qualified to JEDEC J-STD-020 moisture sensitivity level (MSL) 1 and supports both SnPb and lead-free reflow profiles. The "T3H" suffix confirms tape-and-reel packaging with Pb-free construction, and full compliance documentation is available in ON Semiconductor's official product change notices.
How does the 1SMA12AT3H differ from the SZ1SMA12AT3G variant?
The 1SMA12AT3H and SZ1SMA12AT3G share identical electrical specifications, package dimensions, and thermal performance. The "SZ" prefix denotes AEC-Q101 qualification and PPAP capability for automotive applications, including additional process controls and lot traceability. The 1SMA12AT3H is intended for industrial and commercial use, while SZ1SMA12AT3G is certified for underhood automotive deployment - both are interchangeable electrically and mechanically.
Can the 1SMA12AT3H be used for bidirectional transient protection?
No, the 1SMA12AT3H is strictly a unidirectional TVS diode and must not be used for bidirectional protection. It conducts only during reverse-biased overvoltage events and blocks forward current like a standard rectifier. For bidirectional applications such as AC lines or differential data buses, ON Semiconductor offers dedicated devices like the 1SMA12CAT3G - which features symmetrical clamping in both polarities and is explicitly designed for those use cases.
What is the recommended PCB footprint for the 1SMA12AT3H?
The 1SMA12AT3H uses the standard SMA (DO-214AC) footprint per CASE 403D outline, with cathode and anode pads sized for optimal thermal conduction and mechanical stability. ON Semiconductor recommends a minimum 1″ square copper pad on FR-4 for lead-mounted thermal relief, and the datasheet provides exact dimensions: pad width 1.45 mm, length 2.60 mm, spacing 4.32 mm center-to-center. Use of thermal reliefs and adequate ground plane area improves surge current handling and reduces localized heating.
1SMA12AT3H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- -
- Series:
- *
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Unidirectional Channels:
- -
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- -
- Voltage - Breakdown (Min):
- -
- Voltage - Clamping (Max) @ Ipp:
- -
- Current - Peak Pulse (10/1000µs):
- -
- Power - Peak Pulse:
- -
- Power Line Protection:
- -
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
1SMA12AT3H FAQ
1.How can I place an order for 1SMA12AT3H through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA12AT3H 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 1SMA12AT3H reliable?
The price and inventory of 1SMA12AT3H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA12AT3H is usually 5 days.
3.What payment methods are accepted for 1SMA12AT3H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA12AT3H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA12AT3H?
1SMA12AT3H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA12AT3H 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 1SMA12AT3H?
For technical support, including 1SMA12AT3H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA12AT3H requirements.
6.How does Aetrix verify that 1SMA12AT3H is sourced from the original manufacturer or authorized distributors?
All 1SMA12AT3H 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 1SMA12AT3H meets industry standards.
7.What is the process for return or replacement of 1SMA12AT3H?
All 1SMA12AT3H units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA12AT3H, 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 1SMA12AT3H part is unused and in its original packaging.
Return procedure for 1SMA12AT3H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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