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onsemi 1SMC45AT3
- Part No.:
- 1SMC45AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
1SMC45AT3.pdf
- Description:
- TVS DIODE 45VWM 72.2VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:9,571
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Product details
Overview
1SMC45AT3 from ON Semiconductor is a unidirectional 1500 W peak power Zener transient voltage suppressor (TVS) designed for parallel clamping protection of DC power rails and signal lines. It features a 45 V working peak reverse voltage (VRWM), 55.3 V minimum breakdown voltage (VBR) at 1 A, 72.2 V maximum clamping voltage (VC) at 20.6 A peak pulse current, and sub-1 ns response time - deployed in industrial power supplies, automotive ECUs, and medical equipment surge interfaces.
For engineers reviewing the 1SMC45AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin vs. protected IC's absolute maximum rating, VRWM alignment with steady-state bus voltage, thermal derating above 75°C, and UL 497B certification for isolated loop circuit protection.
Technical Context
The 1SMC45AT3 operates as a silicon avalanche diode configured in unidirectional Zener mode, triggered by reverse-biased overvoltage transients. Its junction design delivers low dynamic impedance (<1 Ω typical), enabling rapid transition from high-impedance standby to low-impedance clamping within <1 ns - critical for protecting I/O pins of microcontrollers and communication transceivers against ESD and lightning-induced surges.
Thermal performance is defined by 54.6 °C/W junction-to-lead resistance and 165 °C/W junction-to-ambient resistance on FR-4 board with minimum footprint. It supports 200 A non-repetitive forward surge current (8.3 ms half-sine) and maintains stable VBR temperature coefficient across −65°C to +150°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 45 V - Maximum continuous reverse voltage before clamping begins; must exceed system DC bus voltage (e.g., 36 V nominal automotive rail). |
| VBR @ IT=1 A | 52.65–55.3 V - Breakdown onset range; defines minimum threshold where avalanche conduction initiates reliably. |
| VC @ IPP=20.6 A | 72.2 V - Maximum clamped voltage during 1 ms 1500 W transient; determines worst-case stress on downstream components. |
| PPK | 1500 W @ 1 ms - Peak surge power handling; validates capability against IEC 61000-4-5 Level 4 (4 kV/2 Ω) surges. |
| IR @ VRWM | 5 µA max - Reverse leakage at rated working voltage; ensures negligible standby power loss in battery-powered systems. |
| Response Time | <1 ns - Time from transient rise to clamping onset; enables protection of high-speed interfaces without signal distortion. |
| ESD Rating | Class 3 (>16 kV HBM) - Validated robustness against human-body model electrostatic discharge events. |
Pinout & Package
1SMC45AT3 uses the SMC (DO-214AB) surface-mount package (Case 403), measuring 5.59–6.10 mm × 6.60–7.11 mm × 1.90–2.41 mm (L×W×H), with modified L-bend leads for enhanced pad adhesion and cathode polarity indicated by molded notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse transient return path | Connected to ground or low-impedance return plane; forms current loop with protected line during clamping. |
| Cathode | Clamping voltage reference / Transient sink node | Connected to protected line (e.g., 45 V rail); clamps voltage to ≤72.2 V when transient exceeds VRWM. |
Key Features
| Feature | Design Value |
|---|---|
| UL 497B Recognition (QVGQ2) | Validated for isolated loop circuit protection - meets safety requirements for telecom and industrial fieldbus interfaces. |
| Low Clamping Ratio (VC/VBR ≈ 1.37) | Minimizes overvoltage margin between breakdown and clamp, reducing stress on protected ICs without sacrificing reliability. |
| Pb-Free Surmetic Package | RoHS-compliant thermoset plastic housing with corrosion-resistant, solderable leads - compatible with lead-free reflow profiles (260°C/10 s). |
| High Surge Robustness | Withstands 200 A forward surge (8.3 ms) and 1500 W peak pulse - suitable for harsh environments including automotive load-dump and industrial motor switching. |
| Negligible Capacitance | Typical junction capacitance <100 pF at 0 V - avoids signal integrity degradation on data lines up to 100 Mbps. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) CAN Bus Interface |
|---|---|
|
Use Scenario: 48 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and inductive kickback. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input terminals to clamp transients before they reach upstream rectifier and bulk capacitor. Use Value: Limits voltage to ≤72.2 V during 1500 W surges, preventing damage to 100 V-rated MOSFETs and ensuring uninterrupted operation per IEC 61000-4-5. |
Use Scenario: CAN_H/CAN_L lines in BCM subjected to ESD events and coupled noise from adjacent high-current solenoid drivers. IC Role / Device Role / Timing Role: Dual 1SMC45AT3 devices (one per line) referenced to chassis ground, providing bidirectional-like protection via unidirectional configuration. Use Value: Sub-1 ns response and 16 kV HBM rating suppress ESD pulses before CAN transceiver input stages are overstressed, maintaining ISO 11898-2 compliance. |
| Medical Imaging Equipment Signal Conditioning | Telecom DSL Line Card Surge Protection |
|
Use Scenario: Analog front-end of ultrasound beamformer receiving low-voltage sensor signals vulnerable to EMI-induced transients. IC Role / Device Role / Timing Role: 1SMC45AT3 installed at PCB edge connector, clamping induced surges on bias rails feeding op-amp gain stages. Use Value: 5 µA max leakage preserves signal integrity in µV-level measurements; UL 497B recognition supports regulatory approval for patient-connected devices. |
Use Scenario: Primary protection stage on POTS line interface of DSLAM card, facing lightning-induced longitudinal surges on twisted-pair copper. IC Role / Device Role / Timing Role: Paired 1SMC45AT3 units (tip/ring) referenced to isolation transformer center tap, absorbing common-mode energy before hybrid coupler. Use Value: 1500 W peak power and 72.2 V clamping meet GR-1089-CORE Level 3 requirements while maintaining low insertion loss due to minimal capacitance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ45A (Bourns) | Same VRWM (45 V) and VC (72.2 V), but lower PPK (600 W); SMB package (smaller footprint, higher thermal resistance). | Limited to lower-energy transients (IEC 61000-4-5 Level 2); unsuitable for automotive load-dump or industrial motor drive environments. | Select only if space-constrained and surge threat level is ≤600 W; verify thermal margin on 2-layer board. |
| SMCJ45A (Littelfuse) | Identical VRWM (45 V), VBR (52.65–55.3 V), and PPK (1500 W); same SMC package; minor differences in clamping tolerance (±5% vs ±3%). | Direct functional replacement with identical mounting and electrical behavior; UL 497B certified and AEC-Q200 qualified variants available. | Drop-in alternative where second-source qualification is required; confirm Pb-free status and tape/reel packaging match. |
Compared with 1SMC45AT3, SMBJ45A offers smaller size but sacrifices 60% surge capacity and thermal robustness, while SMCJ45A provides identical protection performance with broader automotive qualification coverage - making it the preferred second source for high-reliability designs.
Availability
1SMC45AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronic control units, and medical diagnostic equipment requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1SMC45AT3 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, cloud, and medical markets.
The 1SMC45AT3 belongs to the SMC-series Zener TVS family engineered for high-energy transient suppression in harsh environments - targeting applications demanding UL 497B compliance, sub-1 ns response, and 1500 W surge immunity.
FAQ
What is the maximum clamping voltage of the 1SMC45AT3 under peak pulse conditions?
The 1SMC45AT3 has a maximum clamping voltage (VC) of 72.2 V when subjected to its rated peak pulse current of 20.6 A (1 ms waveform). This value is guaranteed across temperature and represents the worst-case voltage seen by protected circuitry during a full 1500 W transient event - critical for verifying margin against downstream IC absolute maximum ratings.
Does the 1SMC45AT3 meet UL 497B requirements for isolated loop protection?
Yes, the 1SMC45AT3 is UL Recognized under file E210057 for protector classification per UL 497B. It passed all required tests including Strike Voltage Breakdown, Endurance Conditioning, Dielectric Withstand, and Discharge - confirming suitability for telecom, process control, and other isolated-loop applications where safety-critical surge suppression is mandated.
Can the 1SMC45AT3 be used in bidirectional protection configurations?
No - the 1SMC45AT3 is a unidirectional TVS diode and must be used with cathode tied to the protected line and anode to ground. For true bidirectional protection, two 1SMC45AT3 devices may be back-to-back (anode-to-anode), but this increases capacitance and requires careful layout; dedicated bidirectional parts like 1SMC45CA are recommended instead.
What is the thermal resistance and derating behavior of the 1SMC45AT3 above 75°C?
The 1SMC45AT3 has a junction-to-lead thermal resistance (RJL) of 54.6 °C/W. Its DC power dissipation derates linearly above 75°C at 18.3 mW/°C, dropping from 4.0 W at 75°C to zero at ~297°C (theoretical). For ambient operation >25°C, junction-to-ambient resistance is 165 °C/W, requiring board-level thermal design per ON Semiconductor's Case 403 footprint guidelines.
Is the 1SMC45AT3 RoHS compliant and compatible with lead-free soldering processes?
Yes, the 1SMC45AT3 is offered in a Pb-free Surmetic package (marked with "G" suffix, e.g., 1SMC45AT3G) and qualified for lead-free reflow soldering at 260°C for 10 seconds. The thermoset plastic case and solderable leads meet JEDEC J-STD-020 moisture sensitivity level 1, eliminating pre-bake requirements for standard SMT assembly.
1SMC45AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.2V
- Current - Peak Pulse (10/1000µs):
- 20.6A
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
1SMC45AT3 FAQ
1.How can I place an order for 1SMC45AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMC45AT3 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 1SMC45AT3 reliable?
The price and inventory of 1SMC45AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMC45AT3 is usually 5 days.
3.What payment methods are accepted for 1SMC45AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMC45AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMC45AT3?
1SMC45AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMC45AT3 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 1SMC45AT3?
For technical support, including 1SMC45AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMC45AT3 requirements.
6.How does Aetrix verify that 1SMC45AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMC45AT3 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 1SMC45AT3 meets industry standards.
7.What is the process for return or replacement of 1SMC45AT3?
All 1SMC45AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMC45AT3, 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 1SMC45AT3 part is unused and in its original packaging.
Return procedure for 1SMC45AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMC45AT3 Tags
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