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Semtech Corporation SC621ULTRT
- Part No.:
- SC621ULTRT
- Manufacturer:
- Semtech Corporation
- Category:
- LED Drivers
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
SC621ULTRT.pdf
- Description:
- IC LED DRVR RGLTR / 20MLPQ
- Quantity:
- Payment:
- Shipping:
Inventory:1,817
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Product details
Overview
SC621ULTRT 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 24–40A, 20mΩ dynamic resistance, and 175pF junction capacitance. It protects USB Type-C power delivery buses and load switch inputs in industrial and IoT systems.
For engineers reviewing the SC621ULTRT 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 USB PD and industrial equipment designs.
Technical Context
The SC621ULTRT 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 and −40°C to +125°C due to decreasing RDS(on) under surge conditions.
It operates with reverse stand-off voltage of 22V, breakdown voltage of 25–27.9V, and ultra-low dynamic resistance (20mΩ), enabling superior energy diversion without thermal runaway. Its 175pF capacitance at 22V/1MHz and <600nA leakage support high-speed interfaces while maintaining low standby power.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage | 22V - matches nominal USB PD bus and industrial 24V rail tolerances without derating. |
| Clamping Voltage | 27.5–28V at 24–40A - stays below 30V damage threshold of common load switches and PD controllers. |
| Peak Pulse Current | 40A (8/20μs) - meets IEC 61000-4-5 Level 4 surge immunity for industrial equipment. |
| ESD Withstand | ±30kV contact & air (IEC 61000-4-2) - exceeds automotive and industrial ESD requirements. |
| Dynamic Resistance | 20mΩ - ensures minimal voltage rise under surge, enabling stable clamping independent of current magnitude. |
| Junction Capacitance | 175pF at 22V/1MHz - low enough for USB PD CC/SBU line protection without signal integrity impact. |
| Operating Temp | −40°C to +125°C - supports extended-range operation in enclosed industrial and automotive environments. |
Pinout & Package
SC621ULTRT is housed in a RoHS-compliant DFN-6 package measuring 1.6mm × 1.6mm × 0.55mm with exposed thermal pad (no solder mask defined). All six terminals are required for full 40A surge rating: pins 1–3 serve as low-inductance ground return paths; pins 4–6 form a parallel input node for the protected line.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3 | GND | Common ground connection - all three must be tied to solid ground plane via multiple vias to minimize inductance and maximize surge current handling. |
| 4, 5, 6 | IN | Protected line input - pins connected in parallel to carry full transient current; placement adjacent to connector minimizes coupling into adjacent traces. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-clamp architecture | Clamping voltage varies ≤0.5V across 24–40A and −40°C to +125°C - eliminates design margin uncertainty vs. TVS diodes. |
| FET-based shunt protection | Surge energy dissipated in low-RDS(on) channel instead of PN junction - avoids thermal runaway and enables repeatable surge endurance. |
| Low dynamic resistance | 20mΩ measured between 1A–40A - reduces voltage overshoot during fast-rising transients (e.g., ESD). |
| High EFT immunity | ±4kV per IEC 61000-4-4 (5/50ns, 100kHz/5kHz) - protects against repetitive burst noise in motor drives and PLCs. |
| Space-efficient packaging | 1.6mm × 1.6mm footprint - saves >60% board area versus SO-8 or SOT-23 TVS solutions rated for equivalent surge energy. |
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/5A PD negotiation, exposed to ESD and lightning-induced surges. IC Role / Device Role / Timing Role: Primary EOS shunt device placed directly at connector, clamping transients before they reach PD controller or e-fuse IC. Use Value: Maintains 27.5–28V clamping across temperature and current - prevents overvoltage damage to TI TPS6598x or STUSB4500 PD controllers even at 125°C ambient. |
Use Scenario: Safeguarding input rails of industrial-grade load switches (e.g., ON Semi NIS5132, Diodes Inc. AP22653) in remote meters and robotics. IC Role / Device Role / Timing Role: Front-end transient diverter that limits voltage seen by internal FET gate oxide and drain-source junction. Use Value: Keeps clamping voltage below 30V - avoids gate oxide rupture and avalanche failure in 30V-rated load switches during 1kV/42Ω surges. |
| IoT Edge Node Power Bus Protection | Tablet/Notebook DC-DC Input Protection |
|
Use Scenario: Securing 12–24V input rails of battery-powered IoT gateways subjected to ESD during field servicing and induced surges in factory automation settings. IC Role / Device Role / Timing Role: Single-component solution replacing multi-stage TVS+MOV networks, reducing BOM count and PCB area. Use Value: Delivers 40A surge rating in 1.6mm² - enables compact, fanless enclosure designs without compromising EMC robustness. |
Use Scenario: Protecting buck converter inputs (e.g., MP2451, RT7290B) in portable computing devices where space and thermal constraints limit discrete protection options. IC Role / Device Role / Timing Role: Low-capacitance (175pF), low-leakage (<600nA) protector minimizing standby power loss and signal distortion. Use Value: Enables direct integration upstream of DC-DC enable logic - avoids false shutdowns caused by TVS leakage drift over temperature. |
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 (T22), same tape-and-reel packaging (3,000/reel). | No functional difference - manufactured by same fab, qualified to identical AEC-Q200 stress profiles. | Select SC621ULTRT for standard distribution; TDS2211P.C for direct Semtech channel orders requiring traceable lot codes. |
| uClamp2411ZA | 24V working voltage, ±30kV ESD, but lower 20A IPP rating and higher 33V clamping at 20A - lacks constant-clamp FET architecture. | Better suited for CC/SBU lines than main VBus; not rated for 40A surge or industrial temperature range. | Use uClamp2411ZA only for auxiliary lines; SC621ULTRT remains mandatory for primary 22V bus protection where 40A/125°C capability is required. |
Compared with TDS2211P.C (identical performance, alternate ordering code) and uClamp2411ZA (lower surge rating, higher clamping), SC621ULTRT delivers guaranteed 40A/125°C operation with stable 27.5–28V clamping - making it the sole choice for USB PD 3.0+ and industrial 24V rail protection where reliability under worst-case surge and temperature is non-negotiable.
Availability
SC621ULTRT is available at Aetrix Electronics and suitable for USB Type-C power delivery systems, industrial load switch inputs, and IoT edge node power buses requiring stable component supply with full surge certification and long-term lifecycle support.
Supply support for SC621ULTRT 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 ICs for power management, protection, and signal integrity.
The SC621ULTRT belongs to Semtech's Transient Diverting Suppressor (TDS) family, engineered specifically to replace traditional TVS diodes in high-reliability 20–24V power rail protection where constant clamping and temperature-stable surge handling are critical.
FAQ
What is the exact package type and dimensions of SC621ULTRT?
SC621ULTRT uses a 6-pin DFN package measuring 1.6mm × 1.6mm × 0.55mm with exposed thermal pad. Pin 1 is marked by a laser dot; pins 1–3 are GND, pins 4–6 are IN. The land pattern requires no thermal pad solder mask opening, and all six pins must be connected for full 40A rating. This matches Semtech's official DFN-6 outline drawing Rev 2.5.
Does SC621ULTRT meet IEC 61000-4-5 surge immunity standards?
Yes, SC621ULTRT is rated for 40A peak pulse current (8/20μs waveform) and ±1kV combination wave (1.2/50μs voltage, 8/20μs current, RS = 42Ω), satisfying IEC 61000-4-5 Level 4 for industrial environments. Its 27.5–28V clamping ensures protected ICs remain within safe operating voltage limits during full-rated surge events.
How does SC621ULTRT differ from standard TVS diodes in clamping behavior?
Unlike TVS diodes whose clamping voltage rises linearly with current (VC = VBR + IPP × RDYN), SC621ULTRT uses a triggered FET shunt that maintains 27.5–28V clamping from 24A to 40A and across −40°C to +125°C. This eliminates design margin guesswork and prevents thermal runaway under repeated surges.
Can SC621ULTRT be used for USB Type-C CC line protection?
No - SC621ULTRT is optimized for 22V power bus protection (VBus, load switch inputs) and is not suitable for CC or SBU lines due to its 175pF capacitance. For CC line protection, Semtech recommends uClamp2411ZA (24V, <15pF); SC621ULTRT should be reserved for main power rail protection where low capacitance is not required.
What is the maximum junction temperature and thermal derating guidance for SC621ULTRT?
SC621ULTRT has a maximum junction temperature of +150°C and operates continuously from −40°C to +125°C ambient. No external heatsink is needed: energy is dissipated in the FET channel, not the junction. Layout best practice is to connect all GND pins (1–3) to a solid ground plane using ≥3 vias each to minimize parasitic inductance and maintain clamping stability.
SC621ULTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- mAhXLife™
- 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):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2.5V ~ 5.25V
- Current - Output / Channel:
- 25mA, 400mA (Flash)
- Frequency:
- -
- Dimming:
- -
- Applications:
- Backlight, Camera Flash
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-MLPQ-UT (3x3)
SC621ULTRT FAQ
1.How can I place an order for SC621ULTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for SC621ULTRT 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 SC621ULTRT reliable?
The price and inventory of SC621ULTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC621ULTRT is usually 5 days.
3.What payment methods are accepted for SC621ULTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC621ULTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC621ULTRT?
SC621ULTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC621ULTRT 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 SC621ULTRT?
For technical support, including SC621ULTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC621ULTRT requirements.
6.How does Aetrix verify that SC621ULTRT is sourced from the original manufacturer or authorized distributors?
All SC621ULTRT 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 SC621ULTRT meets industry standards.
7.What is the process for return or replacement of SC621ULTRT?
All SC621ULTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC621ULTRT, 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 SC621ULTRT part is unused and in its original packaging.
Return procedure for SC621ULTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SC621ULTRT Tags
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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BCR420UFD-7
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