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onsemi 1SMB20CAT3
- Part No.:
- 1SMB20CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB20CAT3.pdf
- Description:
- TVS DIODE 20VWM 32.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:4,466
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Product details
Overview
1SMB20CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 20 V working peak reverse voltage (VRWM), 24.5 V clamping voltage (VC) at 18.5 A peak pulse current (IPP), and sub-1 ns response time - deployed in power supplies, automotive ECUs, and industrial control I/O interfaces.
For engineers reviewing the 1SMB20CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin vs. operating bus voltage, VC/IPP trade-off under surge conditions, UL 497B certification for isolated loop protection, and SMB (DO-214AA) thermal performance at 75°C lead temperature.
Technical Context
This bidirectional TVS operates as a voltage-clamped shunt device during transients, leveraging avalanche breakdown to divert surge energy away from downstream circuitry. Its low zener impedance and fast turn-on ensure minimal overshoot when placed close to protected ICs or connectors.
It complies with UL 497B for isolated loop circuit protection and meets Class 3 ESD immunity (>16 kV HBM). The device is rated for non-repetitive 10/1000 µs surges up to 600 W and supports ambient operation from –65°C to +150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 20 V - maximum continuous reverse voltage before clamping begins; must exceed system DC/peak operating voltage. |
| VBR (min/typ/max) | 22.2 V / 23.37 V / 24.5 V at 1 mA - precise breakdown threshold defining clamping onset tolerance. |
| VC @ IPP | 29.2 V at 20.5 A - maximum clamped voltage seen by protected circuit during 10/1000 µs surge. |
| PPK | 600 W @ 1 ms - peak surge power handling capability under standardized non-repetitive pulse. |
| IR @ VRWM | < 5 µA - leakage current level ensuring negligible standby power loss in high-impedance circuits. |
| Response Time | < 1 ns - enables suppression before most logic or analog ICs experience damage from fast EFT or ESD events. |
| UL Recognition | UL 497B (QVGV2, File #116110) - certified for use in safety-critical isolated loop protection applications. |
Pinout & Package
1SMB20CAT3 uses the SMB (DO-214AA) surface-mount package per Case 403A–03 outline: 4.06–4.57 mm length, 3.30–3.81 mm width, 1.90–2.41 mm height, with modified L-bend leads for enhanced pad adhesion. Polarity band is not marked; device is bidirectional and symmetrical.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Anode) | Surge current return path | Both terminals are electrically identical; bidirectional conduction allows placement without orientation check. |
| Anode (Cathode) | Surge current return path | No polarity marking required; simplifies automated placement and eliminates orientation errors in PCB assembly. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC lines or differential buses without polarity constraints. |
| 600 W peak power rating | Handles IEC 61000-4-5 Level 4 surges (4 kV line-earth) with margin in compact SMB footprint. |
| UL 497B recognition | Validated for safety-critical isolated loop protection in telecom and industrial fieldbus systems. |
| < 5 µA leakage @ VRWM | Minimizes quiescent current draw in battery-backed or high-impedance sensor front-ends. |
| Sub-1 ns response | Clamps before transient energy couples into signal paths, critical for high-speed interface protection. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module I/O |
|---|---|
Use Scenario: Protecting 24 V DC input rails against load dump and ISO 7637-2 pulses in PLC power modules. IC Role / Device Role / Timing Role: Shunt TVS placed directly across input terminals to clamp transients before upstream regulators or controllers. Use Value: 29.2 V clamping voltage ensures downstream 3.3 V/5 V regulators remain within absolute maximum ratings during 100 V/50 ms load dump events. |
Use Scenario: Safeguarding LIN bus transceivers and GPIO pins in door module ECUs exposed to battery disconnect spikes. IC Role / Device Role / Timing Role: Bidirectional TVS mounted at connector entry point to absorb ±100 V/50 ms transients per ISO 16750-2. Use Value: UL 497B certification confirms suitability for safety-relevant vehicle subsystems requiring recognized protective components. |
| Medical Equipment Isolated Sensor Interface | POS Terminal RS-232 Port Protection |
Use Scenario: Shielding isolated analog front-ends in patient monitoring devices from ESD and coupling noise on shielded cables. IC Role / Device Role / Timing Role: Low-leakage (≤5 µA) TVS placed across isolated signal lines to prevent baseline shift without loading precision amplifiers. Use Value: Sub-1 ns response prevents ESD-induced latch-up in isolated ADC drivers while maintaining signal integrity in µV-level measurements. |
Use Scenario: Hardening RS-232 driver/receiver pins in retail terminals against hot-plug and ground bounce transients. IC Role / Device Role / Timing Role: Bidirectional TVS connected between TX/RX lines and GND to suppress common-mode surges entering via DB9 connectors. Use Value: 20 V VRWM aligns with RS-232 ±12 V swing range, enabling clamping before receiver input thresholds are exceeded. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ20CA | Same VRWM (20 V), identical SMB package, but lower PPK (600 W same), slightly higher VC (32.4 V @ 18.5 A). | Marginally higher clamping may risk downstream IC stress in tight-voltage-margin designs. | Select 1SMB20CAT3 where VC ≤ 29.2 V is required to meet system-level surge immunity specs. |
| 1.5SMC20CA | Higher PPK (1500 W), larger SMC (DO-214AB) package, same VRWM and VBR range. | Requires PCB area increase (~3× footprint) and higher thermal mass; suited for higher-energy threats. | Choose 1SMB20CAT3 when board space is constrained and 600 W surge capacity suffices per IEC 61000-4-5 Level 3. |
Compared with SMBJ20CA and 1.5SMC20CA, the 1SMB20CAT3 delivers optimal balance of low clamping voltage, UL 497B certification, and compact SMB footprint - making it preferred for space-constrained industrial and automotive I/O protection where precise voltage limiting is critical.
Availability
1SMB20CAT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, medical sensor interfaces, and POS terminal communication ports requiring stable component supply and long-term lifecycle support.
Supply support for 1SMB20CAT3 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, sensors, and discrete devices for automotive, industrial, and cloud power applications.
The 1SMB20CAT3 belongs to the SMB-series transient voltage suppressor family, engineered specifically for robust, surface-mount overvoltage protection in high-reliability industrial and transportation systems.
FAQ
What is the clamping voltage of the 1SMB20CAT3 under standard surge conditions?
The 1SMB20CAT3 exhibits a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPP) of 20.5 A under the 10/1000 µs waveform. This value is measured per industry-standard test conditions and defines the upper voltage limit imposed on protected circuitry during transient events - critical for ensuring downstream ICs remain within their absolute maximum ratings.
Is the 1SMB20CAT3 unidirectional or bidirectional, and how does that affect PCB layout?
The 1SMB20CAT3 is a bidirectional TVS diode, meaning it clamps voltage transients of either polarity symmetrically. As such, no polarity marking is present on the device, and PCB layout requires no orientation verification during placement - reducing assembly errors and enabling simplified routing for AC-coupled or differential signal lines.
Does the 1SMB20CAT3 meet any safety certifications for industrial use?
Yes, the 1SMB20CAT3 carries UL 497B recognition (File #116110, Category QVGV2) for isolated loop circuit protection. This certification validates its performance in safety-critical applications such as industrial fieldbus interfaces, telecom line cards, and medical isolation barriers - covering tests including strike voltage breakdown, endurance conditioning, and dielectric withstand.
What is the maximum operating temperature range for the 1SMB20CAT3?
The 1SMB20CAT3 is rated for an operating and storage temperature range of –65°C to +150°C. Its junction-to-lead thermal resistance (RJL) is 40°C/W, and derating begins above 75°C lead temperature - supporting reliable operation in under-hood automotive environments and high-temperature industrial enclosures.
How does the leakage current of the 1SMB20CAT3 impact low-power designs?
The 1SMB20CAT3 specifies a maximum reverse leakage current (IR) of 5 µA at its 20 V working peak reverse voltage - sufficiently low to avoid measurable loading in high-impedance sensor nodes, battery-backed real-time clocks, or precision reference circuits where microamp-level currents could degrade accuracy or runtime.
1SMB20CAT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 18.5A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 425pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB20CAT3 FAQ
1.How can I place an order for 1SMB20CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB20CAT3 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 1SMB20CAT3 reliable?
The price and inventory of 1SMB20CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB20CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMB20CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB20CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB20CAT3?
1SMB20CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB20CAT3 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 1SMB20CAT3?
For technical support, including 1SMB20CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB20CAT3 requirements.
6.How does Aetrix verify that 1SMB20CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB20CAT3 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 1SMB20CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMB20CAT3?
All 1SMB20CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB20CAT3, 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 1SMB20CAT3 part is unused and in its original packaging.
Return procedure for 1SMB20CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB20CAT3 Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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DESD5V0U1BB-7
Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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