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onsemi 1SMA24AT3G
- Part No.:
- 1SMA24AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMA24AT3G.pdf
- Description:
- 400 W TRANSIENT VOLTAGE SUPPRESS
- Quantity:
- Payment:
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Inventory:270,857
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Product details
Overview
1SMA24AT3G 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 24 V working peak reverse voltage (VRWM), 38.9 V clamping voltage at 10.3 A peak pulse current, and sub-1 ns response time. It is used in automotive power supply protection, industrial PLC I/O modules, and medical equipment surge interfaces.
For engineers reviewing the 1SMA24AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin vs. system operating voltage, clamping voltage headroom relative to protected IC absolute maximum ratings, surge current capability under 10/1000 µs waveform, and SMA package thermal performance on FR-4 PCBs.
Technical Context
The 1SMA24AT3G operates as a unidirectional Zener-based TVS diode with avalanche breakdown behavior. Its clamping action begins at 26.7 V (min VBR @ 1 mA), stabilizes at 28.1 V (nominal), and reaches full clamping at 38.9 V when subjected to 10.3 A (IPP) under standardized 10/1000 µs surge conditions.
It exhibits low dynamic impedance and fast junction response (<1 ns), enabling effective suppression of ESD (Class 3 HBM >16 kV) and lightning-induced surges. The device is rated for continuous operation from –65 °C to +150 °C and requires no bias circuitry-functioning solely as a passive crowbar element across protected nodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 24 V - Maximum continuous reverse voltage before significant leakage; must exceed system DC bus or signal swing. |
| VBR (min/typ/max) | 26.7 / 28.1 / 29.5 V @ 1 mA - Breakdown onset range defining turn-on threshold consistency. |
| VC @ IPP | 38.9 V @ 10.3 A - Clamped voltage during 400 W transient; determines maximum stress on downstream ICs. |
| Peak Pulse Power | 400 W @ 1 ms - Energy-handling capacity for non-repetitive 10/1000 µs surges per REA standard. |
| Junction Capacitance | 500 pF @ 0 V - Minimal impact on high-speed signal integrity below ~10 MHz; suitable for DC/low-frequency rails. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets IEC 61000-4-2 Level 4 for system-level ESD robustness without external RC filtering. |
| Package | SMA (Case 403D-02) - Surface-mount plastic package with cathode band marking; 2.27 mm max height, 4.57 mm width. |
Pinout & Package
SMA package (Case 403D-02) is a surface-mount, two-terminal, unidirectional TVS diode with molded cathode polarity band. Dimensions: 4.57 mm × 2.27 mm × 1.52 mm (L × W × H); thermal resistance RJA = 250 °C/W on FR-4 board with minimum footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Anode of internal Zener junction | Connected to higher-potential node (e.g., VBUS); reverse-biased during normal operation. |
| Anode | Cathode of internal Zener junction | Connected to reference/ground; completes clamping path during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Handles 10/1000 µs transients up to 10.3 A without degradation-sufficient for ISO 7637-2 Pulse 1/2/5a in 12 V automotive systems. |
| 24 V VRWM with 38.9 V VC | Provides ≥10 V margin between clamping voltage and typical 28 V industrial rail, preventing latch-up in protected regulators or controllers. |
| <1 ns response time | Activates before most microcontroller I/O pins can be damaged by ESD or fast-rising transients-critical for USB, CAN, and sensor interface protection. |
| Pb-free Surmetic™ package | RoHS-compliant SMA construction with corrosion-resistant finish and 260 °C solderability-supports lead-free reflow and long-term field reliability. |
| –65 °C to +150 °C operation | Validated for under-hood automotive, industrial control cabinets, and medical enclosures where ambient extremes exceed commercial grade limits. |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital Input Protection |
|---|---|
|
Use Scenario: Suppresses load dump spikes (up to 60 V, 100 ms) and alternator ripple on 24 V battery-fed ECUs. IC Role / Device Role / Timing Role: Passive crowbar clamping element placed directly across input filter capacitor, upstream of DC/DC converter. Use Value: Limits transient voltage to ≤38.9 V, protecting 40 V-rated input MOSFETs and LDOs without derating or oversized input capacitors. |
Use Scenario: Guards 24 V digital input channels against field-wiring induced surges (IEC 61000-4-4, 4 kV) in factory automation systems. IC Role / Device Role / Timing Role: Standoff protector mounted at connector entry point, shunting energy before optocoupler or Schmitt trigger input stage. Use Value: Prevents false triggering and latch-up in isolated inputs while maintaining <1 µA leakage at 24 V nominal-no signal attenuation or timing skew. |
| Medical Equipment ESD Interface Protection | Telecom DC Power Feed Protection |
|
Use Scenario: Shields RS-485 transceivers and analog front-end ADCs from operator ESD events in portable diagnostic devices. IC Role / Device Role / Timing Role: Unidirectional TVS placed on each signal line (A/B) and VCC rail, referenced to chassis ground. Use Value: Withstands >16 kV HBM discharges while adding only 500 pF capacitance-preserves signal rise time and common-mode rejection above 1 MHz. |
Use Scenario: Protects PoE-powered endpoint equipment (e.g., IP cameras) from surges entering via 48 V DC feed lines. IC Role / Device Role / Timing Role: Primary overvoltage clamp on PSE-side DC input, coordinated with secondary TVS and fuse for staged protection. Use Value: Delivers 400 W clamping at 38.9 V-compatible with IEEE 802.3af/at voltage windows and avoids premature shutdown during benign inrush. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A | Same VRWM (24 V), but SMB package (higher RJA = 300 °C/W); 600 W peak power; 43.5 V VC @ 13.8 A. | Higher clamping voltage and lower thermal efficiency-requires larger copper area for same power dissipation. | Select SMBJ24A only if board layout allows SMB footprint and system tolerates 4.6 V higher clamping than 1SMA24AT3G. |
| 1N6267A | Same SMA package, but older DO-214AC variant; 24 V VRWM, 38.9 V VC @ 10.3 A; identical electrical specs but non-Pb-free. | No RoHS compliance; obsolete for new designs requiring lead-free manufacturing. | Choose 1SMA24AT3G over 1N6267A when Pb-free compliance, traceable sourcing, and extended product lifecycle support are required. |
Compared with SMBJ24A and 1N6267A, the 1SMA24AT3G offers optimal balance of low-profile SMA packaging, verified Pb-free construction, and precise 38.9 V clamping-making it preferred for space-constrained, high-reliability 24 V industrial and automotive applications where thermal management and regulatory compliance are critical.
Availability
1SMA24AT3G is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, and medical instrumentation requiring stable component supply, consistent parametric performance, and long-term manufacturability assurance.
Supply support for 1SMA24AT3G 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, sensors, and discrete devices for automotive, industrial, and communications markets.
The 1SMA24AT3G belongs to ON Semiconductor's SMA-series unidirectional TVS family, engineered for high-energy transient suppression in cost-sensitive, high-volume applications where reliability under harsh electrical environments is mandatory.
FAQ
What is the clamping voltage of the 1SMA24AT3G and how is it measured?
The 1SMA24AT3G has a clamping voltage (VC) of 38.9 V measured at 10.3 A peak pulse current (IPP) under standardized 10/1000 µs waveform conditions. This value is specified in the Electrical Characteristics table on page 3 of the official ON Semiconductor datasheet (Rev. 10, November 2007). It represents the maximum voltage seen across the device during surge conduction and is critical for ensuring downstream components remain within safe operating limits. The 1SMA24AT3G maintains this clamping performance consistently across its qualified temperature range.
Is the 1SMA24AT3G unidirectional or bidirectional, and how does that affect circuit placement?
The 1SMA24AT3G is a unidirectional TVS diode, meaning it conducts only during reverse-bias overvoltage events-its cathode must be connected to the higher-potential node (e.g., VBUS or signal line), and its anode to ground or reference. This configuration blocks forward conduction during normal operation, ensuring negligible leakage (<2.5 µA at 24 V). Unlike bidirectional variants, it cannot protect AC signals or dual-polarity rails without additional components. Correct polarity alignment is confirmed by the molded cathode band on the SMA package.
What is the maximum operating temperature range for the 1SMA24AT3G?
The 1SMA24AT3G is rated for an operating and storage temperature range of –65 °C to +150 °C, as stated in the Maximum Ratings table (page 2 of the datasheet). This wide range supports deployment in under-hood automotive environments, industrial control cabinets exposed to ambient extremes, and medical devices requiring sterilization compatibility. Junction temperature must remain within this window during surge events; derating curves in Figure 3 confirm usable pulse power decreases linearly above 75 °C ambient.
Does the 1SMA24AT3G meet RoHS requirements, and what does the "G" suffix indicate?
Yes, the "G" suffix in 1SMA24AT3G explicitly denotes a Pb-free (RoHS-compliant) version packaged in ON Semiconductor's Surmetic™ molding compound. Per the datasheet footnote on page 3, "The 'G' suffix indicates Pb-Free package available." The device meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements and supports lead-free reflow profiles up to 260 °C for 10 seconds. This makes the 1SMA24AT3G suitable for modern electronics manufacturing without exemption requests or process deviations.
How does the 1SMA24AT3G compare to the 1SMA24A (non-G) variant?
The 1SMA24AT3G and 1SMA24A share identical electrical specifications-including VRWM (24 V), VBR (26.7–29.5 V), VC (38.9 V), and peak power (400 W)-but differ in environmental compliance. The "G" suffix confirms Pb-free construction, whereas the base 1SMA24A uses leaded terminations. Mechanically, both use the same SMA (Case 403D-02) package with identical dimensions and thermal characteristics. For new designs targeting RoHS, REACH, or export compliance, the 1SMA24AT3G is the mandatory choice; legacy 1SMA24A may only be used in exempted or non-regulated applications.
1SMA24AT3G 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:
- -
1SMA24AT3G FAQ
1.How can I place an order for 1SMA24AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA24AT3G 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 1SMA24AT3G reliable?
The price and inventory of 1SMA24AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA24AT3G is usually 5 days.
3.What payment methods are accepted for 1SMA24AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA24AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA24AT3G?
1SMA24AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA24AT3G 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 1SMA24AT3G?
For technical support, including 1SMA24AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA24AT3G requirements.
6.How does Aetrix verify that 1SMA24AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMA24AT3G 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 1SMA24AT3G meets industry standards.
7.What is the process for return or replacement of 1SMA24AT3G?
All 1SMA24AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA24AT3G, 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 1SMA24AT3G part is unused and in its original packaging.
Return procedure for 1SMA24AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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