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onsemi 1SMB28CAT3
- Part No.:
- 1SMB28CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB28CAT3.pdf
- Description:
- TVS DIODE 28VWM 45.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:8,051
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Product details
Overview
1SMB28CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 28 V working peak reverse voltage (VRWM), 34.4 A maximum peak pulse current (IPP), 45.4 V clamping voltage (VC) at IPP, and sub-1 ns response time - deployed in power supplies, automotive ECUs, and industrial control interfaces to absorb lightning-induced surges and ESD events.
For engineers reviewing the 1SMB28CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ circuit operating voltage, VC margin relative to protected IC absolute maximum ratings, UL 497B certification for isolated loop compliance, and SMB package thermal performance under repetitive surge conditions.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, enabling robust protection in AC-coupled or floating signal paths without polarity constraints. Its low zener impedance (<1 Ω typical) and fast avalanche turn-on ensure minimal overshoot during <1 ns transients, critical for safeguarding high-speed communication lines and microcontroller I/Os.
The device uses silicon avalanche junction technology with thermally optimized Surmetic SMB (DO-214AA) packaging, delivering 40 °C/W junction-to-lead thermal resistance and rated for continuous operation from –65 °C to +150 °C. It meets Class 3 HBM ESD immunity (>16 kV) and UL 497B recognition for isolated loop circuit protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 28 V - must match or exceed DC/peak operating voltage of protected circuit to avoid leakage or false triggering |
| VBR @ IT=1 mA | 31.1–34.4 V - breakdown threshold range defining reliable avalanche conduction onset under surge conditions |
| VC @ IPP | 45.4 V - maximum clamped voltage seen by downstream components during 34.4 A 1 ms transient |
| IPP | 34.4 A - peak surge current capability at 1 ms pulse width, derated linearly above 25 °C ambient |
| IR @ VRWM | <5 µA - ensures negligible standby power loss and no interference with low-current sensor or bias networks |
| Response Time | <1 ns - enables suppression before logic-level transients propagate into CMOS inputs or ADC front-ends |
| ESD Rating | Class 3 HBM (>16 kV) - qualifies for direct handling in unshielded assembly environments without additional ESD buffers |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, void-free thermosetting plastic case per Case Outline 403A–03; dimensions: 4.06 × 3.30 × 2.11 mm (L × W × H); polarity band not marked (bidirectional).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Anode for reverse polarity) | Surge current return path | Connected to system ground or low-impedance reference plane to complete clamping loop during positive/negative transients |
| Anode (Cathode for reverse polarity) | Surge current input node | Placed directly across protected line (e.g., VBUS, RS-485 A/B, CAN H/L) to shunt energy before reaching load |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC signals, differential buses (CAN, RS-485), and floating power rails without polarity concerns |
| UL 497B recognition | Validates suitability for telecom and industrial isolated loop applications requiring certified surge withstand per safety standard |
| 600 W peak power rating | Supports IEC 61000-4-5 Level 4 (4 kV line-earth, 2 kV line-line) surge testing with margin in compact SMB footprint |
| Low clamping ratio (VC/VBR ≈ 1.45) | Minimizes voltage stress on downstream ICs compared to higher-ratio suppressors, preserving design margin |
| Solderable L-bend leads | Ensures reliable reflow attachment on FR-4 PCBs with ON Semiconductor's recommended 2500-unit tape-and-reel packaging |
Applications
| Automotive Power Distribution | Industrial RS-485 Networks |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs against load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional TVS placed between VBAT and chassis ground to clamp transients up to 120 V/300 ms. Use Value: 45.4 V clamping ensures MCU power rails remain below 5.5 V absolute max while surviving 600 W surges. |
Use Scenario: Safeguarding RS-485 transceivers in factory automation nodes exposed to motor drive noise and ground bounce. IC Role / Device Role / Timing Role: Paired devices across A–GND and B–GND to suppress common-mode and differential surges simultaneously. Use Value: Sub-1 ns response prevents data corruption during 10 kV EFT bursts; UL 497B supports certified fieldbus deployment. |
| Medical Equipment Power Inputs | AC-DC Adapter Secondary Side |
Use Scenario: Shielding isolated DC outputs of patient-connected power supplies from mains-borne transients per IEC 60601-1. IC Role / Device Role / Timing Role: Installed across secondary-side output capacitor terminals to limit voltage excursions during surge events. Use Value: 28 V VRWM aligns with 24 V nominal outputs; 5 µA leakage avoids compromising isolation barrier integrity. |
Use Scenario: Clamping flyback transformer leakage spikes and rectifier reverse recovery transients in 5–24 V adapters. IC Role / Device Role / Timing Role: Mounted across secondary winding or output rectifier to absorb 100 ns–1 ms energy pulses. Use Value: 40 °C/W RJL enables sustained operation at 75 °C lead temperature without derating in confined enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ28CA | Same VRWM (28 V), identical SMB package, but lower 400 W peak power rating and 48.4 V VC @ IPP | Limited to lower-energy transients (IEC 61000-4-5 Level 3); unsuitable where 600 W margin is required | Select when cost sensitivity outweighs surge margin needs and layout space is constrained to SMB footprint |
| 1.5SMC28CA | Higher 1500 W rating, DO-214AB (SMC) package (7.11 × 6.22 mm), 45.7 V VC @ IPP, same VRWM | Requires larger PCB area; better for high-reliability industrial systems with frequent surge exposure | Choose when long-term field reliability under repeated 10/1000 µs surges justifies added board space and cost |
Compared with SMBJ28CA and 1.5SMC28CA, the 1SMB28CAT3 delivers optimal balance of 600 W surge capacity, SMB footprint compatibility, and UL 497B certification - making it preferred for space-constrained, safety-certified designs where 1.5SMC28CA's size is prohibitive and SMBJ28CA's power rating is insufficient.
Availability
1SMB28CAT3 is available at Aetrix Electronics and suitable for automotive power distribution, industrial RS-485 networks, and medical equipment power inputs requiring stable component supply, full traceability, and lifecycle continuity.
Supply support for 1SMB28CAT3 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 1SMB28CAT3 belongs to the 1SMBxxCAT3 series of bidirectional TVS diodes engineered for high-energy transient suppression in compact surface-mount form - targeting cost-sensitive, high-volume applications demanding UL recognition and proven surge robustness.
FAQ
What is the clamping voltage of the 1SMB28CAT3 under maximum surge conditions?
The 1SMB28CAT3 exhibits a maximum clamping voltage (VC) of 45.4 V when subjected to its rated peak pulse current (IPP) of 34.4 A with a 1 ms exponential waveform. This value is measured per Figure 2 in the official datasheet and defines the upper voltage limit imposed on protected circuits during worst-case transients. The 1SMB28CAT3 maintains this clamping performance across its specified operating temperature range.
Is the 1SMB28CAT3 suitable for protecting CAN bus lines?
Yes, the 1SMB28CAT3 is well-suited for CAN bus protection due to its bidirectional structure, 28 V VRWM matching typical 24 V CAN systems, and sub-1 ns response time that prevents data corruption during ESD or EFT events. Its UL 497B recognition further validates use in certified industrial CAN networks. The 1SMB28CAT3 should be placed as close as possible to the CAN transceiver pins with minimal trace inductance.
Does the 1SMB28CAT3 have polarity marking on the package?
No, the 1SMB28CAT3 does not feature a polarity band or marking on its SMB (DO-214AA) package because it is a bidirectional TVS diode. Both terminals are functionally symmetrical - either can serve as anode or cathode depending on transient polarity. This eliminates orientation errors during automated placement and simplifies layout for differential or AC-coupled protection schemes involving the 1SMB28CAT3.
What is the maximum operating temperature for the 1SMB28CAT3?
The 1SMB28CAT3 has an operating and storage temperature range of –65 °C to +150 °C, with thermal performance validated up to 150 °C junction temperature. Its 40 °C/W junction-to-lead thermal resistance allows reliable operation at 75 °C lead temperature without derating, and it remains functional beyond that with appropriate ambient derating per Figure 3 in the datasheet. This makes the 1SMB28CAT3 viable for under-hood automotive and high-temperature industrial environments.
How does the 1SMB28CAT3 differ from unidirectional TVS diodes like the 1SMB28AT3?
The 1SMB28CAT3 is bidirectional, providing symmetrical clamping for both positive and negative transients, whereas the unidirectional 1SMB28AT3 only clamps in one direction and requires correct polarity installation. The 1SMB28CAT3's breakdown voltage range (31.1–34.4 V) and clamping behavior are identical in both directions, making it ideal for AC, differential, or floating systems. In contrast, the 1SMB28AT3 offers slightly tighter VBR tolerance but demands strict attention to anode/cathode routing - a distinction critical when selecting between the two variants of the 1SMB28CAT3 family.
1SMB28CAT3 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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 13.2A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 310pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB28CAT3 FAQ
1.How can I place an order for 1SMB28CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB28CAT3 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 1SMB28CAT3 reliable?
The price and inventory of 1SMB28CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB28CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMB28CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB28CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB28CAT3?
1SMB28CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB28CAT3 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 1SMB28CAT3?
For technical support, including 1SMB28CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB28CAT3 requirements.
6.How does Aetrix verify that 1SMB28CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB28CAT3 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 1SMB28CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMB28CAT3?
All 1SMB28CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB28CAT3, 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 1SMB28CAT3 part is unused and in its original packaging.
Return procedure for 1SMB28CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB28CAT3 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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ESD5Z5.0T1G
onsemi
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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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