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onsemi 1SMC33AT3
- Part No.:
- 1SMC33AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMC33AT3.pdf
- Description:
- TVS DIODE 33V 53.3V SMC
- Quantity:
- Payment:
- Shipping:
Inventory:4,552
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Product details
Overview
1SMC33AT3 from ON Semiconductor is a unidirectional 33 V working peak reverse voltage, 1500 W peak pulse power Zener transient voltage suppressor (TVS) in SMC (DO-214AB) package. It clamps transients to 53.3 V at 28.1 A peak pulse current, features <1 ns response time and 5 µA max leakage at 33 V, and is widely deployed for surge protection in industrial power supplies and automotive ECUs.
For engineers reviewing the 1SMC33AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin vs. protected circuit's absolute maximum rating, VRWM alignment with DC bus voltage, UL 497B certification for isolated loop compliance, and thermal derating above 75°C ambient.
Technical Context
This unidirectional TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents high impedance (<5 µA leakage at VRWM), then avalanches sharply at VBR = 36.7–40.6 V to divert surge current away from downstream ICs. Its low dynamic impedance and sub-nanosecond turn-on minimize overshoot during fast transients like ESD or inductive switching spikes.
The device uses a planar Zener junction structure in thermoset plastic SURMETIC™ packaging, rated for 260°C/10s soldering, with cathode polarity marked by a molded notch. Thermal resistance from junction-to-lead is 54.6°C/W, enabling robust 1500 W (1 ms, 10/1000 µs waveform) surge handling when mounted on adequate copper area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33 V - Maximum continuous reverse operating voltage; must be ≥ system DC bus or signal swing to avoid leakage-induced heating |
| VBR @ IT=1 A | 36.7–40.6 V - Breakdown onset range; defines minimum clamping threshold under standardized test current |
| VC @ IPP=28.1 A | 53.3 V - Clamped voltage during 1500 W surge; determines maximum stress seen by protected ICs |
| IPP | 28.1 A - Peak pulse current at 1500 W; used to size series impedance (e.g., fuse, resistor) limiting fault energy |
| Response Time | <1 ns - Enables suppression of fast transients (e.g., ESD, relay bounce) before sensitive logic is damaged |
| Leakage @ VRWM | <5 µA - Ensures negligible standby power loss and no false triggering in low-power circuits |
| UL 497B | Certified - Validated for use in isolated telecom/data line protection per Underwriters Laboratories safety standard |
Pinout & Package
Package: SMC (DO-214AB), surface-mount, void-free thermosetting plastic case with modified L-bend leads; cathode indicated by molded notch; 5.59–6.10 mm width × 6.60–7.11 mm length × 1.90–2.41 mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to ground or lowest potential point in protected circuit; carries full surge return current |
| Cathode | High-side clamp node | Connected to protected line (e.g., 33 V rail); avalanche conduction occurs from cathode to anode during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| 1500 W peak pulse power (1 ms) | Handles severe surges such as IEC 61000-4-5 Level 4 (4 kV/2 Ω) without degradation when properly heatsinked |
| Clamping ratio VC/VBR ≈ 1.45 | Provides tight voltage control-critical for protecting 3.3 V or 5 V logic powered from 33 V intermediate rails |
| ESD rating >16 kV HBM | Eliminates need for additional ESD diodes in board-level ESD protection schemes |
| UL 497B recognition | Validates suitability for telecom/data line isolation barriers without requiring custom safety testing |
| Pb-free SURMETIC™ package | Complies with RoHS and J-STD-020 reflow profiles; lead finish ensures reliable solder joint formation |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 33 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Shunt clamping element placed directly across input terminals to limit transient voltage to ≤53.3 V. Use Value: Prevents damage to upstream rectifier and downstream DC-DC controllers by clamping 1500 W surges within 1 ns. |
Use Scenario: 33 V battery-supplied lighting control circuit in BCM subjected to alternator load dump events. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power rail, coordinated with upstream fuse and PCB trace inductance. Use Value: Maintains microcontroller operation during 12 V system load dump transients by holding rail voltage below 53.3 V. |
| Medical Imaging Equipment Interface | Telecom Isolated Data Line Protection |
Use Scenario: 33 V auxiliary supply rail feeding analog front-end sensors in MRI subsystems vulnerable to ESD and cable discharge. IC Role / Device Role / Timing Role: Fast-response shunt suppressor placed adjacent to connector entry point to intercept transients before reaching precision ADCs. Use Value: Limits ESD-induced latch-up risk with <1 ns response and <5 µA leakage preserving signal integrity. |
Use Scenario: Secondary-side protection on isolated RS-485 or CAN bus lines referenced to 33 V local ground in telecom base station backplane. IC Role / Device Role / Timing Role: UL 497B-certified clamp ensuring isolation barrier integrity during lightning-induced surges. Use Value: Meets safety-critical isolation requirements while clamping common-mode transients to 53.3 V without compromising data rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMC33AT3G | Automotive-grade variant; AEC-Q101 qualified, PPAP capable, identical electrical specs and package | Required for automotive OEM designs; same footprint and performance but with extended reliability validation | Select 1SMC33AT3 for industrial/commercial use; choose SZ1SMC33AT3G only when automotive qualification is mandated |
| SMCJ33A | Same SMC package, 33 V VRWM, but 1500 W rating per JEDEC standards; slightly higher VC = 54.5 V at 27.5 A | Broader distributor availability; minor clamping voltage difference may affect margin in 3.3 V logic protection | Acceptable alternative if 1.2 V higher clamping voltage is acceptable; verify layout compatibility with identical SMC outline |
Compared with SZ1SMC33AT3G, the 1SMC33AT3 lacks AEC-Q101 certification but offers identical surge performance and footprint; versus SMCJ33A, it provides tighter clamping (53.3 V vs. 54.5 V) and UL 497B recognition-critical for telecom isolation compliance.
Availability
1SMC33AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronic control units, and medical imaging equipment requiring stable component supply with consistent surge rating and UL certification.
Supply support for 1SMC33AT3 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 connectivity solutions for automotive, industrial, and cloud power applications.
The 1SMC33AT3 belongs to the SMC-series Zener TVS family, engineered for high-energy transient suppression in harsh environments where reliability, fast response, and safety certification are mandatory.
FAQ
What is the maximum clamping voltage of the 1SMC33AT3 under surge conditions?
The 1SMC33AT3 clamps to a maximum of 53.3 V when subjected to its rated 28.1 A peak pulse current (1500 W, 1 ms). This value is measured per the 10/1000 µs waveform defined in IEC 61000-4-5 and represents the highest voltage the protected circuit will experience during a full-rated surge event. Designers must ensure downstream components tolerate this clamped voltage with margin.
Does the 1SMC33AT3 meet UL safety standards for isolated circuit protection?
Yes, the 1SMC33AT3 is UL 497B recognized (File #E210057) for use in isolated loop circuit protection. This certification validates its performance in telecom and data line isolation barriers-including passing strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge tests-not just flammability of the package material.
What is the thermal resistance and power derating behavior of the 1SMC33AT3?
The 1SMC33AT3 has a junction-to-lead thermal resistance (RJL) of 54.6°C/W and junction-to-ambient (RJA) of 165°C/W. Its DC power dissipation derates linearly above 75°C lead temperature (4.0 W at 75°C → 0 W at 150°C) and above 25°C ambient (0.75 W at 25°C → 0 W at 150°C), per the datasheet's Figure 3 derating curve.
How does the 1SMC33AT3 differ from the automotive-grade SZ1SMC33AT3G variant?
The 1SMC33AT3 and SZ1SMC33AT3G share identical electrical specifications, package, and marking-but the SZ-prefix part undergoes AEC-Q101 stress testing and supports PPAP documentation for automotive OEMs. The 1SMC33AT3 is intended for industrial and commercial applications where automotive qualification is not required.
Can the 1SMC33AT3 be used in bidirectional transient protection applications?
No, the 1SMC33AT3 is strictly unidirectional, with cathode and anode terminals clearly defined and polarity marked by a molded notch. Bidirectional protection requires separate devices such as the SMBJ33CA or SMAJ33CA; using the 1SMC33AT3 in reverse-biased configurations will not provide symmetrical clamping.
1SMC33AT3 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:
- -
1SMC33AT3 FAQ
1.How can I place an order for 1SMC33AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMC33AT3 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 1SMC33AT3 reliable?
The price and inventory of 1SMC33AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMC33AT3 is usually 5 days.
3.What payment methods are accepted for 1SMC33AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMC33AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMC33AT3?
1SMC33AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMC33AT3 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 1SMC33AT3?
For technical support, including 1SMC33AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMC33AT3 requirements.
6.How does Aetrix verify that 1SMC33AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMC33AT3 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 1SMC33AT3 meets industry standards.
7.What is the process for return or replacement of 1SMC33AT3?
All 1SMC33AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMC33AT3, 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 1SMC33AT3 part is unused and in its original packaging.
Return procedure for 1SMC33AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMC33AT3 Tags
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