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Semtech Corporation SC643ULTRT
- Part No.:
- SC643ULTRT
- Manufacturer:
- Semtech Corporation
- Category:
- LED Drivers
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
SC643ULTRT.pdf
- Description:
- IC LED DRIVER RGLTR 25MA 20MLPQ
- Quantity:
- Payment:
- Shipping:
Inventory:2,403
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Product details
Overview
SC643ULTRT from Semtech is a Transient Diverting Suppressor (TDS) designed for high-energy EOS protection of 22V-rated power or I/O lines, featuring ±30kV IEC 61000-4-2 ESD immunity, 40A peak pulse current (8/20μs), 27.5–28V clamping voltage at 40A, 20mΩ dynamic resistance, and 175pF junction capacitance - deployed in USB Type-C PD input protection and industrial load switch front-end circuits.
For engineers reviewing the SC643ULTRT datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, DFN-6 package layout guidance, real-world clamping stability across temperature and current, and validated alternatives for 22V bus protection in high-reliability embedded and power delivery systems.
Technical Context
The SC643ULTRT uses a surge-rated FET as its primary protection element, activated by a precision trigger circuit that turns on the shunt path when transient voltage exceeds breakdown. Unlike conventional TVS diodes, its clamping voltage remains nearly constant (27.5–28V) across 24–40A peak pulse current and −40°C to +125°C operating temperature due to decreasing RDS(on) under surge conditions.
It operates with a 22V reverse stand-off voltage and 25–27.9V breakdown voltage, delivering low 20mΩ dynamic resistance and 130–600nA leakage at VRWM. Its 175pF capacitance at 22V/1MHz supports compatibility with medium-speed power bus interfaces without signal integrity compromise.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage | 22V - defines maximum continuous DC or RMS operating voltage on protected line without leakage or conduction. |
| Clamping Voltage | 27.5–28V at 40A (8/20μs) - ensures downstream 24V-rated ICs (e.g., USB PD controllers, load switches) remain below damage threshold during surge events. |
| Peak Pulse Current | 40A (8/20μs) - meets IEC 61000-4-5 Level 4 industrial surge immunity requirements for 22V systems. |
| ESD Withstand | ±30kV contact & air (IEC 61000-4-2) - provides robust handling of human-body-model ESD events in portable and connector-facing applications. |
| Junction Capacitance | 175pF at 22V/1MHz - low enough to avoid signal distortion on 20V power rails while enabling compact PCB placement near connectors. |
| Dynamic Resistance | 20mΩ - enables stable clamping by minimizing voltage rise (ΔV = IPP × RDYN) across full surge current range. |
Pinout & Package
SC643ULTRT is housed in a RoHS-compliant, halogen-free DFN package measuring 1.6mm × 1.6mm × 0.55mm with 6 leads and UL 94V-0 molding compound. All pins must be soldered for rated surge performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1, 2, 3 | GND | Common ground return path for surge current; all three must be connected with low-inductance vias to maximize 40A capability. |
| Pins 4, 5, 6 | IN | Protected line input (e.g., VBUS, load switch input); parallel connection ensures uniform current sharing and thermal distribution during transients. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-clamp architecture | Clamping voltage varies ≤0.5V from 24A to 40A (8/20μs), eliminating design margin inflation needed with traditional TVS diodes. |
| Temperature-stable protection | Clamping remains 27.5–28V from −40°C to +125°C - critical for industrial and automotive under-hood environments. |
| Low dynamic resistance | 20mΩ enables efficient energy diversion with minimal self-heating, supporting repeated surge events without derating. |
| High-energy surge rating | 1120W peak pulse power (8/20μs) allows single-device compliance with IEC 61000-4-5 ±1kV (RS = 42Ω) on 22V buses. |
Applications
| USB Type-C Power Delivery Protection | Industrial Load Switch Input Protection |
|---|---|
Use Scenario: Protecting VBUS lines in USB-C ports supporting up to 20V/5A PD negotiation against ESD and lightning-induced surges. IC Role / Device Role / Timing Role: Primary front-end transient suppressor placed between connector and USB PD controller or buck converter input. Use Value: Maintains 27.5V clamping at 40A and 125°C - prevents overvoltage damage to 24V-tolerant PD controllers where standard TVS would exceed 35V at same conditions. |
Use Scenario: Safeguarding enable and input pins of high-side load switches (e.g., HS2950P) in remote meters, robotics, and IoT edge nodes exposed to field surges. IC Role / Device Role / Timing Role: Shunt protector that diverts transient energy before it reaches the load switch's internal FET gate or drain. Use Value: Limits stress on load switch RDS(on) and OVP circuitry by clamping below 28V - avoids latch-up or permanent gate oxide damage during 1.2/50μs combo-wave events. |
| Notebook/Tablet VBUS Rail Protection | Industrial Equipment 24V Power Input Stage |
Use Scenario: Securing main 20V power rail in thin-client notebooks and tablets against connector hot-plug transients and ESD coupling. IC Role / Device Role / Timing Role: Low-capacitance (175pF), high-power suppressor co-located with USB-C receptacle to minimize trace inductance. Use Value: Enables compact 1.6×1.6mm footprint without sacrificing 40A surge rating - reduces board area vs. discrete TVS+MOV solutions by >60%. |
Use Scenario: Front-end protection for 24V DC input on programmable logic controllers (PLCs), motor drives, and sensor hubs in factory automation. IC Role / Device Role / Timing Role: First-line defense against induced surges from relay switching, inductive loads, and nearby lightning strikes. Use Value: Delivers stable 27.5V clamping across −40°C to +125°C ambient - ensures consistent protection during uncontrolled thermal cycling in enclosures without active cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TDS2211P.C | Identical electrical specs, same DFN-6 package, identical marking code "T22" - direct Semtech-manufactured variant with tape-and-reel packaging (3,000 pcs/reel). | No functional difference; used interchangeably in production where reel quantity and date-code traceability are required. | Select TDS2211P.C when sourcing from authorized Semtech distributors with full lot traceability and standard volume packaging. |
| SMAJ22A | Standard unidirectional TVS diode; 22V VRWM, 35.1V VC @ 12.3A (8/20μs), higher clamping, no constant-clamp behavior, 100pF capacitance. | Limited to lower-energy surges; clamping rises with temperature and current - unsuitable for 40A or high-temp industrial use without significant derating. | Choose SMAJ22A only for cost-sensitive, non-critical 22V lines where 35V clamping is acceptable and peak current stays below 15A. |
Compared with TDS2211P.C (identical function, packaging, and spec compliance) and SMAJ22A (higher clamping, lower surge rating), SC643ULTRT offers guaranteed 27.5V clamping at 40A and full temperature stability - making it the preferred choice for USB PD, industrial load switches, and thermally demanding 22V power rail protection.
Availability
SC643ULTRT is available at Aetrix Electronics and suitable for USB Type-C PD implementations, industrial load switch front-ends, and notebook/tablet 22V power rail protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SC643ULTRT 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
Semtech Corporation is a U.S.-based fabless semiconductor company specializing in high-performance analog and mixed-signal semiconductors for power management, protection, and signal integrity.
SC643ULTRT belongs to Semtech's Transient Diverting Suppressor (TDS) product line, engineered to replace conventional TVS diodes in high-reliability 22V power and interface protection where stable clamping and temperature resilience are mandatory.
FAQ
What is the maximum continuous operating voltage for SC643ULTRT?
The SC643ULTRT has a reverse stand-off voltage (VRWM) of 22V, meaning it can continuously block up to 22V DC or RMS without significant leakage. This makes it suitable for nominal 20V USB PD VBUS rails and 24V industrial power inputs where transient headroom is required. Exceeding 22V risks premature conduction and accelerated degradation.
How does SC643ULTRT differ from standard TVS diodes in clamping behavior?
Unlike standard TVS diodes whose clamping voltage rises linearly with peak pulse current (VC = VBR + IPP × RDYN), the SC643ULTRT uses a triggered FET architecture that maintains clamping at 27.5–28V from 24A to 40A. This eliminates the need for over-specifying surge rating to meet voltage thresholds - a key advantage in USB PD and industrial designs.
Can SC643ULTRT be used for bidirectional signal line protection?
No - SC643ULTRT is a unidirectional device intended for DC power or single-ended I/O line protection (e.g., VBUS, load switch input). It conducts only from IN to GND. For bidirectional data lines like USB DP/DM or RS-485, Semtech recommends low-capacitance TVS arrays such as RClamp3371ZC or uClamp2411ZA instead of SC643ULTRT.
What is the recommended PCB layout for optimal SC643ULTRT performance?
Place SC643ULTRT within 2mm of the protected connector. Connect all three IN pins (4,5,6) via a single short, wide trace to the protected line, and tie all three GND pins (1,2,3) directly to a solid ground plane using ≥3 thermal vias. Avoid stubs or splits - parasitic inductance degrades clamping response during fast ESD events.
Is SC643ULTRT compliant with RoHS and halogen-free standards?
Yes - SC643ULTRT is Pb-free, halogen-free, and fully compliant with RoHS and WEEE directives. Its molding compound meets UL 94V-0 flammability rating, and lead finish is matte tin. The device is qualified for reflow soldering per J-STD-020 moisture sensitivity level 1 (MSL-1), with unlimited floor life at ≤30°C/60% RH.
SC643ULTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- SemPulse®
- Package/Case:
- 20-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 5
- Voltage - Supply (Min):
- 2.9V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2.5V ~ 5.25V
- Current - Output / Channel:
- 25mA
- Frequency:
- -
- Dimming:
- -
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-MLPQ-UT (3x3)
SC643ULTRT FAQ
1.How can I place an order for SC643ULTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for SC643ULTRT 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 SC643ULTRT reliable?
The price and inventory of SC643ULTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC643ULTRT is usually 5 days.
3.What payment methods are accepted for SC643ULTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC643ULTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC643ULTRT?
SC643ULTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC643ULTRT 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 SC643ULTRT?
For technical support, including SC643ULTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC643ULTRT requirements.
6.How does Aetrix verify that SC643ULTRT is sourced from the original manufacturer or authorized distributors?
All SC643ULTRT 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 SC643ULTRT meets industry standards.
7.What is the process for return or replacement of SC643ULTRT?
All SC643ULTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC643ULTRT, 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 SC643ULTRT part is unused and in its original packaging.
Return procedure for SC643ULTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SC643ULTRT Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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