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onsemi 1.5SMC18AT3
- Part No.:
- 1.5SMC18AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1.5SMC18AT3.pdf
- Description:
- TVS DIODE 15.3VWM 25.2VC SMC
- Quantity:
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Inventory:8,437
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Product details
Overview
1.5SMC18AT3 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 15.3 V working peak reverse voltage (VRWM), 18 V breakdown voltage (VBR) at 1 mA test current, 25.2 V maximum clamping voltage (VC) at 59.5 A peak pulse current, and sub-1 ns response time - deployed in automotive power supplies, industrial PLC I/O modules, and medical equipment surge interfaces.
For engineers reviewing the 1.5SMC18AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin above operating voltage, VC vs. system withstand rating, UL 497B certification for isolated loop protection, and SMC package thermal performance under repetitive surge conditions.
Technical Context
The 1.5SMC18AT3 operates as a silicon avalanche diode with Zener-based breakdown mechanism, optimized for single-pulse transient suppression per IEC 61000-4-5 (10/1000 µs waveform). Its low dynamic impedance (<0.4 Ω typical) ensures stable clamping across 1–100 A surge currents, while the thermally robust Surmetic™ SMC package enables 4.0 W DC power dissipation at 75°C lead temperature.
It exhibits a +0.088 %/°C temperature coefficient of VBR, enabling predictable voltage drift over –65°C to +150°C operating range. The device is rated for 200 A non-repetitive forward surge current (8.3 ms half-sine), supporting high-energy event handling without latch-up or thermal runaway.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 15.3 V - minimum continuous reverse voltage before leakage exceeds 5 µA; sets upper limit for safe DC operating voltage |
| VBR @ IT=1 mA | 18 V (min–max: 17.1–18.9 V) - precise Zener conduction onset; defines threshold for transient clamping activation |
| VC @ IPP=59.5 A | 25.2 V - maximum clamped voltage during 1 ms 1500 W surge; must be below protected circuit's absolute max rating |
| PPK | 1500 W @ 1 ms - peak pulse power capability per non-repetitive 10×1000 µs waveform; determines energy absorption capacity |
| IR @ VRWM | <5 µA - ultra-low reverse leakage ensures minimal standby power loss and no false triggering in high-impedance circuits |
| Response Time | <1 ns - enables clamping before most microsecond-scale transients (e.g., ESD, inductive kickback) propagate into ICs |
| UL Recognition | UL 497B QVGV2 - certified for isolated loop circuit protection; validates reliability in telecom and safety-critical interfaces |
Pinout & Package
1.5SMC18AT3 uses the SMC (Case 403) surface-mount package: void-free thermosetting plastic body with modified L-bend leads, cathode indicated by molded notch, and 7.75–8.13 mm length × 6.60–7.11 mm width × 1.90–2.41 mm height. Rated for 260°C soldering (10 s).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during reverse-biased clamping | Connected to ground or low-impedance return path; carries full surge current during transient events |
| Cathode | High-side connection to protected line | Connected to supply rail or signal line; voltage referenced to anode; polarity notch identifies this terminal |
Key Features
| Feature | Design Value |
|---|---|
| 1500 W peak pulse power | Handles IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) on 24 V systems without degradation |
| UL 497B recognition | Validated for use in isolated loop protectors - required for industrial fieldbus and analog sensor interfaces |
| ESD rating >16 kV HBM | Eliminates need for secondary ESD protection on board-level inputs exposed to human contact |
| Low zener impedance | Dynamic impedance <0.4 Ω ensures minimal VC rise across 1–100 A surge range - critical for tight voltage margins |
| –65°C to +150°C operation | Supports under-hood automotive, outdoor industrial, and sterilizable medical applications without derating |
Applications
| Automotive Power Distribution | Industrial PLC Analog Inputs |
|---|---|
Use Scenario: Protection of 12 V/24 V battery-fed ECUs against load dump and alternator ripple transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp spikes up to 120 V. Use Value: 25.2 V clamping voltage ensures MCU and CAN transceivers remain within 36 V absolute maximum rating during ISO 7637-2 Pulse 5a events. |
Use Scenario: Guarding 4–20 mA current loop inputs in programmable logic controllers against wiring fault surges. IC Role / Device Role / Timing Role: Parallel-connected TVS on loop supply line, referenced to isolated ground plane. Use Value: UL 497B certification confirms compliance with isolated loop protection requirements in hazardous-area instrumentation. |
| Medical Sensor Interfaces | AC-DC Power Supply Outputs |
Use Scenario: Surge hardening of patient-connected ECG/EEG front-end amplifiers against defibrillator discharge coupling. IC Role / Device Role / Timing Role: Low-leakage (≤5 µA) TVS on signal path to preserve DC accuracy while blocking >1 kV transients. Use Value: Sub-1 ns response prevents transient propagation past input RC filters - maintaining signal integrity during IEC 60601-1 testing. |
Use Scenario: Output rail clamping in 12 V/5 V SMPS units to prevent overvoltage damage during feedback loop failure. IC Role / Device Role / Timing Role: Fast-acting shunt device triggered when output exceeds 15.3 V, diverting excess energy to ground. Use Value: 1500 W peak power rating sustains multiple 100 ms overvoltage events without parametric shift or thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18A | Same VRWM (15.4 V) and VBR (18 V), but lower PPK (600 W); SMB package (smaller footprint, higher RJA) | Limited to lower-energy transients (IEC 61000-4-5 Level 2); unsuitable for load dump or high-current industrial surges | Select when board space is constrained and surge energy is ≤600 W - verify thermal margin at 75°C ambient |
| 1.5KE18A | Same electrical specs, but axial DO-201 package; higher thermal resistance (RJA = 200°C/W vs. 165°C/W) | Requires through-hole mounting; incompatible with automated SMT assembly; less effective for fast transients due to lead inductance | Choose only for legacy through-hole designs or prototyping; avoid in high-frequency or high-volume production |
Compared with SMBJ18A and 1.5KE18A, the 1.5SMC18AT3 delivers superior surge energy handling (1500 W vs. 600 W/1500 W axial), better thermal performance in SMT layouts, and UL 497B certification - making it the preferred choice for new industrial and automotive designs requiring robust, standards-compliant protection.
Availability
1.5SMC18AT3 is available at Aetrix Electronics and suitable for automotive electronics, industrial control systems, and medical device power interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for 1.5SMC18AT3 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 part of onsemi) is a global semiconductor supplier specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and cloud power applications.
The 1.5SMC18AT3 belongs to the SMC-series transient voltage suppressors - engineered for high-energy surge immunity in harsh environments, with emphasis on reliability, UL certification, and surface-mount manufacturability.
FAQ
What is the working peak reverse voltage (VRWM) of the 1.5SMC18AT3?
The 1.5SMC18AT3 has a VRWM of 15.3 V, meaning it can continuously block up to this voltage in reverse bias while maintaining leakage current below 5 µA. This value ensures compatibility with 12 V nominal systems where transient margins require ≥15 V standoff, and directly informs placement upstream of voltage regulators or downstream of DC-DC converters.
How does the clamping voltage (VC) of the 1.5SMC18AT3 compare to its breakdown voltage (VBR)?
The 1.5SMC18AT3 has a VBR of 18 V (at 1 mA) and a VC of 25.2 V (at 59.5 A), resulting in a 7.2 V differential - reflecting its low dynamic impedance design. This small VC–VBR spread ensures predictable voltage limiting during high-current surges, critical for protecting 24 V-rated components that cannot tolerate excursions beyond 28 V.
Is the 1.5SMC18AT3 certified for use in safety-critical isolation barriers?
Yes, the 1.5SMC18AT3 carries UL 497B recognition (File #116110, QVGV2 category) specifically for isolated loop circuit protection. This certification validates its performance in medical and industrial isolation interfaces - unlike generic TVS diodes lacking third-party verification for barrier integrity under surge stress.
What is the maximum surge current the 1.5SMC18AT3 can handle without degradation?
The 1.5SMC18AT3 is rated for a peak pulse current (IPP) of 59.5 A under 1 ms 10×1000 µs waveform conditions. It also supports 200 A non-repetitive forward surge current (8.3 ms half-sine), enabling reliable operation in high-energy scenarios like automotive load dump or motor drive switching noise - provided PCB layout minimizes parasitic inductance.
Does the 1.5SMC18AT3 have a specified temperature coefficient, and why does it matter?
Yes, the 1.5SMC18AT3 has a maximum temperature coefficient of +0.088 %/°C for VBR. This means its breakdown voltage increases by ~15.8 mV per °C rise - a key parameter for designs operating across –40°C to +125°C, ensuring clamping remains effective at both cold start and hot idle conditions without premature conduction or insufficient protection.
1.5SMC18AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- -
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- -
1.5SMC18AT3 FAQ
1.How can I place an order for 1.5SMC18AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1.5SMC18AT3 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 1.5SMC18AT3 reliable?
The price and inventory of 1.5SMC18AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1.5SMC18AT3 is usually 5 days.
3.What payment methods are accepted for 1.5SMC18AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1.5SMC18AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1.5SMC18AT3?
1.5SMC18AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1.5SMC18AT3 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 1.5SMC18AT3?
For technical support, including 1.5SMC18AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1.5SMC18AT3 requirements.
6.How does Aetrix verify that 1.5SMC18AT3 is sourced from the original manufacturer or authorized distributors?
All 1.5SMC18AT3 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 1.5SMC18AT3 meets industry standards.
7.What is the process for return or replacement of 1.5SMC18AT3?
All 1.5SMC18AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1.5SMC18AT3, 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 1.5SMC18AT3 part is unused and in its original packaging.
Return procedure for 1.5SMC18AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1.5SMC18AT3 Tags
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ESD9B5.0ST5G
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DESD3V3E1BL-7B
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Diodes Incorporated
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Diodes Incorporated
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