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Semtech Corporation SC221ULTRT
- Part No.:
- SC221ULTRT
- Manufacturer:
- Semtech Corporation
- Package:
- 8-UFDFN Exposed Pad
- Datasheet:
-
SC221ULTRT.pdf
- Description:
- IC REG BUCK ADJ 650MA 8MLPD
- Quantity:
- Payment:
- Shipping:
Inventory:2,255
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Product details
Overview
SC221ULTRT from Semtech is a transient diverting suppressor designed for high-energy EOS protection of 22V-rated I/O or power lines, featuring ±30kV IEC 61000-4-2 ESD immunity, 40A (8/20μs) peak pulse current handling, and a stable 27.5–28V clamping voltage across temperature and current range - deployed in USB Type-C PD input protection and industrial load switch front-end circuits.
For engineers reviewing the SC221ULTRT datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage stability under 40A surge, DFN-6 thermal and layout performance, 175pF junction capacitance at 22V, and compatibility with 22V bus systems requiring robust EOS resilience without TVS-like voltage drift.
Technical Context
The SC221ULTRT 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 - enabling near-constant clamping voltage independent of peak pulse current magnitude. Its dynamic resistance is 20mΩ (8/20μs), ensuring minimal voltage rise during high-current surges.
Unlike conventional TVS diodes, the SC221ULTRT maintains clamping voltage within 27.5–28V from −40°C to +125°C and across 24A–40A IPP, due to the FET's decreasing RDS(on) under surge conditions. It supports unsymmetrical line protection per IEC 61000-4-5 with ±1kV (1.2/50μs, RS = 42Ω) compliance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage | 22V - defines maximum continuous DC operating voltage on protected line without leakage or degradation |
| Clamping Voltage | 27.5–28V at 40A (8/20μs) - ensures downstream 24V-tolerant ICs (e.g., USB PD controllers) remain below damage threshold |
| Peak Pulse Current | 40A (8/20μs) - meets IEC 61000-4-5 Level 4 industrial surge immunity requirements |
| ESD Withstand | ±30kV contact & air (IEC 61000-4-2) - exceeds Class 4 ESD immunity for handheld and connector-facing applications |
| Junction Capacitance | 175pF at 22V, 1MHz - low enough for 22V power rail protection without signal integrity impact |
| Dynamic Resistance | 20mΩ (8/20μs) - enables stable clamping by minimizing IR drop increase with rising surge current |
| Reverse Leakage | 600nA max at 22V - negligible power loss in always-on 22V bus monitoring applications |
Pinout & Package
SC221ULTRT is housed in a Pb-free, RoHS-compliant DFN-6 package measuring 1.6mm × 1.6mm × 0.55mm with UL 94V-0 molding compound. All six terminals are surface-mount; no thermal pad required - energy dissipation occurs internally via the shunt FET.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1, 2, 3 | GND | Common ground return path for surge current - all three must be connected to maximize current sharing and minimize parasitic inductance |
| Pins 4, 5, 6 | IN | Protected line input - tied together to form single high-current path to 22V bus or power rail; enables full 40A rating |
Key Features
| Feature | Design Value |
|---|---|
| Constant-clamp architecture | Clamping voltage remains ≤28V from −40°C to +125°C and 24A–40A IPP - eliminates thermal derating design margins required for TVS diodes |
| Surge-rated FET protection core | Replaces pn-junction TVS with low-RDS(on) shunt switch - reduces clamping voltage by ~10V vs. comparable 22V TVS at 125°C |
| High-energy EFT immunity | ±4kV per IEC 61000-4-4 (5/50ns, 5kHz & 100kHz) - protects against repetitive fast transients in industrial control environments |
| Space-optimized DFN-6 footprint | 1.6mm × 1.6mm area - saves >50% board space vs. SO-8 or SOT-23 alternatives rated for equivalent 40A surge |
| Lead-free & halogen-free | RoHS/WEEE compliant with UL 94V-0 flammability - meets global environmental and safety compliance for consumer and industrial end equipment |
Applications
| USB Type-C Power Delivery Protection | Industrial Load Switch Input Protection |
|---|---|
Use Scenario: Protecting VBus lines in USB-C receptacles supporting up to 20V/100W PD negotiation, exposed to ESD and lightning-induced surges. IC Role / Device Role / Timing Role: Primary front-end EOS suppressor placed between connector and PD controller or load switch - operates as voltage-triggered shunt during transients. Use Value: Maintains 27.5–28V clamping across temperature, preventing overvoltage damage to 24V-tolerant PD controllers even at 125°C ambient. |
Use Scenario: Safeguarding input pins of industrial-grade load switches (e.g., HS2950P) in remote meters, robotics, and IoT gateways subjected to 1kV surge events. IC Role / Device Role / Timing Role: Transient diverting element placed directly at load switch VIN pin - clamps surges before they stress internal FET gate oxide or drain-source junction. Use Value: Limits clamping voltage to ≤28V, staying well below typical 30V+ absolute maximum ratings of industrial load switches - extends reliability in harsh environments. |
| Notebook/Tablet 22V Power Rail Protection | IoT Device Battery Input Protection |
Use Scenario: Securing 22V auxiliary power rails in thin-client notebooks and tablets where space and thermal constraints limit discrete TVS options. IC Role / Device Role / Timing Role: Single-component 22V rail protector replacing multi-device TVS arrays - handles both ESD and surge with one DFN-6 device. Use Value: 175pF capacitance avoids power rail instability; 1.6mm × 1.6mm footprint enables placement adjacent to connectors without routing compromises. |
Use Scenario: Protecting Li-ion battery input stages in battery-powered IoT sensors and edge nodes exposed to ESD during field servicing or docking. IC Role / Device Role / Timing Role: Standby-mode protector on battery feed line - blocks ±30kV ESD while drawing only 600nA leakage at 22V. Use Value: Ultra-low leakage preserves battery shelf life; constant clamping prevents false shutdown or BMS fault triggering during transient events. |
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 | Same die, identical electrical specs, identical DFN-6 package - differs only in tape-and-reel packaging (3,000 pcs/reel vs. SC221ULTRT's unspecified reel count) | No functional difference; used interchangeably in USB-C and industrial designs per Semtech documentation | Select TDS2211P.C when standard 7″ reel logistics are required; SC221ULTRT may reflect alternate distribution channel or marking variant |
| uClamp2411ZA | 24V working voltage, lower 24A IPP rating, higher 30V clamping, smaller 0.65mm × 0.65mm DFN-2 package - optimized for CC/SBU lines, not power rails | Designed for low-capacitance data-line protection (CC, SBU), not 22V power bus protection - insufficient for 40A surge handling | Use uClamp2411ZA only for auxiliary signal lines; SC221ULTRT remains mandatory for main VBus or load switch input protection |
Compared with TDS2211P.C, SC221ULTRT offers identical protection performance but may differ in traceability or distribution labeling; versus uClamp2411ZA, SC221ULTRT delivers 67% higher surge current capacity and 2.5V lower clamping - making it the sole suitable choice for 22V power rail front-end protection.
Availability
SC221ULTRT is available at Aetrix Electronics and suitable for USB Type-C PD interfaces, industrial load switch inputs, notebook 22V power rails, and battery-fed IoT device protection requiring stable component supply and long-term EOS resilience.
Supply support for SC221ULTRT 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, sensing, and connectivity.
The SC221ULTRT belongs to Semtech's Transient Diverting Suppressor (TDS) family - engineered to replace conventional TVS diodes in high-energy EOS applications where stable clamping, temperature independence, and compact size are critical.
FAQ
What is the maximum continuous operating voltage for SC221ULTRT?
The SC221ULTRT has a reverse stand-off voltage (VRWM) of 22V, meaning it can continuously withstand up to 22V DC on its IN pins relative to GND without significant leakage or degradation. This makes SC221ULTRT suitable for 22V power rails, USB PD VBus, and industrial 24V nominal systems operating within tolerance.
Does SC221ULTRT require a thermal pad on the PCB?
No, SC221ULTRT does not require a thermal pad. Its DFN-6 package dissipates surge energy internally via the shunt FET, and the datasheet explicitly states "no thermal pad is needed." Instead, robust grounding using all three GND pins (1, 2, 3) and multiple vias to the ground plane is recommended to minimize inductance and maximize surge current handling.
How does SC221ULTRT 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), SC221ULTRT uses a triggered FET to maintain clamping voltage at 27.5–28V across 24A–40A and from −40°C to +125°C - eliminating thermal derating and enabling predictable protection margins in SC221ULTRT-based designs.
Can SC221ULTRT protect high-speed data lines like USB SuperSpeed?
No, SC221ULTRT is not intended for high-speed data lines. With 175pF junction capacitance, it is optimized for 22V power rails and low-frequency I/O protection. For USB SuperSpeed (TX/RX), Semtech recommends low-capacitance devices like RClamp3371ZC (<0.25pF); SC221ULTRT should be used only on VBus, CC, or load switch inputs.
What is the ESD rating of SC221ULTRT and how is it verified?
SC221ULTRT is rated for ±30kV contact discharge and ±30kV air discharge per IEC 61000-4-2. This rating is validated through standardized ESD gun testing with the ESD return path connected to an ESD ground plane, as documented in the official Semtech TDS2211P datasheet - the same silicon and test protocol apply to SC221ULTRT.
SC221ULTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- -
- Package/Case:
- 8-UFDFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Not For New Designs
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 650mA
- Frequency - Switching:
- 20MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MLPD-UT (2x2)
SC221ULTRT FAQ
1.How can I place an order for SC221ULTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for SC221ULTRT 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 SC221ULTRT reliable?
The price and inventory of SC221ULTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC221ULTRT is usually 5 days.
3.What payment methods are accepted for SC221ULTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC221ULTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC221ULTRT?
SC221ULTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC221ULTRT 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 SC221ULTRT?
For technical support, including SC221ULTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC221ULTRT requirements.
6.How does Aetrix verify that SC221ULTRT is sourced from the original manufacturer or authorized distributors?
All SC221ULTRT 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 SC221ULTRT meets industry standards.
7.What is the process for return or replacement of SC221ULTRT?
All SC221ULTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC221ULTRT, 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 SC221ULTRT part is unused and in its original packaging.
Return procedure for SC221ULTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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