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onsemi 1SMA12AT3G
- Part No.:
- 1SMA12AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA12AT3G.pdf
- Description:
- TVS DIODE 12VWM 19.9VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:3,611
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Product details
Overview
1SMA12AT3G from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping overvoltage transients in DC power rails and signal lines. It features a 12 V working peak reverse voltage (VRWM), 14.0 V nominal breakdown voltage (VBR) at 1 mA test current, 19.9 V clamping voltage (VC) at 20.1 A peak pulse current, and <1 ns response time. It is used in automotive power supply protection and industrial control I/O interfaces.
For engineers reviewing the 1SMA12AT3G datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, package dimensions, clamping behavior under surge, thermal derating curves, and direct alternatives with documented differences in VRWM, VC, and capacitance.
Technical Context
The 1SMA12AT3G operates as a unidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transient voltages above its VRWM of 12 V. Its clamping action begins at VBR = 13.3–14.7 V (min–max) and limits peak reverse voltage to 19.9 V at 20.1 A IPP, ensuring downstream ICs remain within safe operating limits during ESD or lightning-induced surges.
It exhibits low zener impedance and fast response (<1 ns), enabling effective suppression of sub-microsecond transients. The device is rated for 400 W peak power (10/1000 µs waveform), 0.5 W steady-state dissipation at 25°C ambient, and supports operation from −65°C to +150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 12 V - Maximum continuous reverse voltage before clamping begins; must be ≥ circuit's normal operating voltage. |
| VBR @ IT=1 mA | 14.0 V (nominal) - Breakdown initiates here; ensures reliable turn-on margin above VRWM. |
| VC @ IPP=20.1 A | 19.9 V - Clamped voltage seen by protected circuit during 400 W transient; defines maximum stress on downstream components. |
| IPP | 20.1 A - Peak pulse current capability at 10/1000 µs waveform; determines survivability against defined surge events. |
| CJ @ 0 V, 1 MHz | 925 pF - Junction capacitance affecting high-frequency signal integrity; critical for data line protection. |
| IR @ VRWM | 2.5 µA - Reverse leakage at 12 V; low value minimizes standby power loss and avoids false triggering. |
| Response Time | <1 ns - Enables suppression of ultrafast ESD pulses (IEC 61000-4-2) before damage occurs. |
Pinout & Package
The 1SMA12AT3G is housed in an SMA (DO-214AC) surface-mount package (Case 403D), featuring a low-profile, flat-handling design suitable for top-slide or bottom-board mounting. Polarity is marked by a cathode band; maximum soldering temperature is 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | High-side connection to protected line | Reverse-biased terminal; connects to the rail needing overvoltage clamping (e.g., +12 V supply). |
| Anode | Reference/ground return path | Connects to system ground or lower-potential reference; completes clamping current path during transient events. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 µs) | Withstands automotive load-dump and industrial surge events without degradation. |
| ESD rating >16 kV (HBM Class 3) | Provides robust immunity to human-body-model electrostatic discharge in handling and field operation. |
| Low profile SMA package (2.1 × 4.3 mm) | Enables compact placement near connectors or IC power pins without sacrificing board area. |
| AEC-Q101 qualified (SZ-prefix variant) | Validated for automotive under-hood and infotainment applications requiring extended reliability. |
| Pb-free, RoHS-compliant construction | Meets global environmental compliance requirements and supports lead-free reflow assembly. |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs from load dump transients (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role: Unidirectional TVS placed between battery rail and regulator input. Use Value: Clamps transients to ≤19.9 V, preventing overvoltage shutdown or latch-up in LDOs and microcontrollers. |
Use Scenario: Safeguarding 24 V digital input modules in programmable logic controllers against induced surges from relay switching. IC Role / Device Role: Front-end transient suppressor on isolated input channels before optocoupler or Schmitt trigger. Use Value: Limits voltage excursion to 19.9 V at 20.1 A, preserving signal integrity and avoiding false edge detection. |
| Medical Equipment Power Supply Input | Telecom Line Card Surge Protection |
Use Scenario: Shielding auxiliary 12 V DC-DC converter inputs in diagnostic imaging systems from mains-coupled transients. IC Role / Device Role: Primary overvoltage clamp on secondary-side power distribution bus. Use Value: Delivers 400 W surge handling with 925 pF capacitance-low enough to avoid interfering with 100 kHz feedback loops. |
Use Scenario: Protecting Ethernet PHY power pins (e.g., +12 V bias) on telecom line cards exposed to lightning-induced surges. IC Role / Device Role: Secondary-level TVS after primary gas discharge tube (GDT), absorbing residual energy. Use Value: Fast <1 ns response captures residual fast-rising edges missed by slower GDTs, reducing let-through energy. |
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 | Same VRWM (12 V), higher IPP (24.7 A), lower VC (20.1 V → 19.9 V), larger SMB package (4.6 × 3.6 mm vs. 2.1 × 4.3 mm). | Higher surge margin but occupies ~2.5× PCB area; better for high-reliability industrial designs with layout margin. | Select SMBJ12A when board space permits and peak surge current exceeds 20.1 A in worst-case testing. |
| 1N6135A | Same VRWM (12 V), lower peak power (300 W), higher VC (21.2 V at 18.8 A), axial DO-41 package. | Not surface-mount; requires through-hole assembly and manual rework; unsuitable for automated SMT lines. | Choose 1N6135A only for legacy through-hole designs or prototyping where reflow compatibility is not required. |
Compared with 1SMA12AT3G, SMBJ12A offers higher surge headroom in a larger footprint, while 1N6135A trades power and mounting flexibility for legacy compatibility-neither is pin-compatible, and both require layout revision.
Availability
1SMA12AT3G is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, and medical power supply designs requiring stable component supply, AEC-Q101 traceability, and RoHS-compliant sourcing.
Supply support for 1SMA12AT3G 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 communications markets.
The 1SMA12AT3G belongs to ON Semiconductor's SMA-series transient voltage suppressors-a family engineered for high-energy surge clamping in cost-sensitive, high-volume applications demanding reliability and Pb-free compliance.
FAQ
What is the maximum clamping voltage of the 1SMA12AT3G under standard surge conditions?
The 1SMA12AT3G clamps to 19.9 V at a peak pulse current (IPP) of 20.1 A, measured using the industry-standard 10/1000 µs double-exponential waveform. This value is guaranteed across temperature and represents the highest voltage downstream components will experience during a 400 W transient event. The 1SMA12AT3G maintains this performance with minimal variation up to +125°C junction temperature.
Is the 1SMA12AT3G suitable for protecting USB or CAN signal lines?
No-the 1SMA12AT3G is not recommended for USB or CAN signal line protection due to its 925 pF junction capacitance, which would severely attenuate high-speed signals and violate USB 2.0 or CAN FD timing specifications. For such interfaces, low-capacitance TVS devices like the ESD9X5.0ST5G (12 pF) or NUP4114MR6T1G (3.5 pF) are appropriate alternatives. The 1SMA12AT3G is intended for power rail and low-speed I/O protection only.
Does the 1SMA12AT3G meet AEC-Q101 qualification?
The base 1SMA12AT3G is not AEC-Q101 qualified; however, its automotive-grade counterpart SZ1SMA12AT3G is fully AEC-Q101 qualified and PPAP capable. Both share identical electrical specs and SMA package, but the SZ-prefix version undergoes additional process controls, lot traceability, and stress testing per automotive standards. For automotive production, specify SZ1SMA12AT3G-not 1SMA12AT3G-to ensure compliance.
How does thermal derating affect the 1SMA12AT3G's surge capability at elevated ambient temperatures?
The 1SMA12AT3G's peak pulse power remains unchanged up to +75°C ambient, but its steady-state power dissipation derates linearly above that point: 20 mW/°C reduction from 1.5 W at 75°C. While short-duration transients (≤1 ms) are largely unaffected by ambient temperature, repeated surges in high-temp environments require verification of junction temperature rise using RJA = 250°C/W. At 100°C ambient, the 1SMA12AT3G retains full 400 W pulse rating but must avoid sustained DC leakage accumulation.
Can the 1SMA12AT3G replace a 12 V Zener diode for voltage regulation?
No-the 1SMA12AT3G is optimized for transient suppression, not precision DC regulation. Its VBR tolerance is ±5% (13.3–14.7 V), and it lacks tight dynamic impedance or low-noise characteristics required for regulation. Under continuous DC bias, its 2.5 µA leakage at 12 V is acceptable, but power dissipation would exceed 0.5 W above ~25°C ambient, risking thermal runaway. Use dedicated Zener regulators like the MMBZ5242B for voltage reference applications instead of the 1SMA12AT3G.
1SMA12AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 20.1A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 925pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA12AT3G FAQ
1.How can I place an order for 1SMA12AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA12AT3G 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 1SMA12AT3G reliable?
The price and inventory of 1SMA12AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA12AT3G is usually 5 days.
3.What payment methods are accepted for 1SMA12AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA12AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA12AT3G?
1SMA12AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA12AT3G 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 1SMA12AT3G?
For technical support, including 1SMA12AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA12AT3G requirements.
6.How does Aetrix verify that 1SMA12AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMA12AT3G 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 1SMA12AT3G meets industry standards.
7.What is the process for return or replacement of 1SMA12AT3G?
All 1SMA12AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA12AT3G, 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 1SMA12AT3G part is unused and in its original packaging.
Return procedure for 1SMA12AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA12AT3G Tags
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