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Semtech Corporation SC185QULTRT
- Part No.:
- SC185QULTRT
- Manufacturer:
- Semtech Corporation
- Package:
- 16-UFQFN Exposed Pad
- Datasheet:
-
SC185QULTRT.pdf
- Description:
- IC REG BUCK 3.3V 4A 16MLPQ
- Quantity:
- Payment:
- Shipping:
Inventory:1,659
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Product details
Overview
SC185QULTRT 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, and 20mΩ dynamic resistance. It protects USB PD and Type-C VBus lines in industrial and portable electronics.
For engineers reviewing the SC185QULTRT datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, DFN-6 package layout guidance, temperature-stable clamping behavior, and direct alternatives for load-switch input protection and high-voltage interface surge hardening.
Technical Context
The SC185QULTRT 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 across 24–40A and −40°C to +125°C due to decreasing RDS(on) under surge conditions.
It operates with a 22V reverse stand-off voltage (VRWM), 25–27.9V breakdown (VBR), and 175pF junction capacitance at 22V/1MHz - optimized for low-impact integration on high-speed power rails without signal integrity degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage | 22V - matches USB PD 20V nominal bus with 2V margin for transients. |
| Clamping Voltage | 27.5–28V at 24–40A (1.2/50μs + 8/20μs combo wave) - stays below 29V damage threshold of common 30V-rated load switches. |
| Peak Pulse Current | 40A (8/20μs) - satisfies IEC 61000-4-5 Level 4 (±1kV, RS = 42Ω) for industrial equipment. |
| ESD Withstand | ±30kV contact & air (IEC 61000-4-2) - exceeds USB IF and IEC 61000-4-2 Class 4 requirements. |
| Dynamic Resistance | 20mΩ - enables stable clamping independent of current magnitude and temperature drift. |
| Junction Capacitance | 175pF at 22V/1MHz - low enough to avoid degrading rise/fall times on 20V power rails with typical trace impedances. |
Pinout & Package
SC185QULTRT is housed in a RoHS-compliant DFN 1.6mm × 1.6mm × 0.55mm 6-lead package with exposed thermal pad not required; all pins must be connected for full 40A rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3 | GND | Common ground return path - all three pins must be tied to PCB ground plane via multiple vias to minimize inductance during 40A surge events. |
| 4, 5, 6 | IN | Protected line input - connects directly to VBus or power rail; all three pins are internally paralleled and must be shorted externally for rated surge performance. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-clamp architecture | Clamping voltage varies ≤0.5V across 24–40A and −40°C to +125°C - eliminates derating uncertainty in thermal design. |
| FET-based shunt protection | Replaces pn-junction TVS with <0.1Ω effective RDS(on) - dissipates energy in channel rather than junction, improving reliability under repeated surges. |
| Low dynamic resistance | 20mΩ measured between 1A–40A (8/20μs) - ensures minimal IR drop and predictable voltage limiting during fast-rising transients. |
| High EFT immunity | ±4kV per IEC 61000-4-4 (5/50ns, 5kHz & 100kHz) - protects against burst noise in motor drives and industrial PLCs. |
Applications
| USB Type-C Power Delivery Bus Protection | Industrial Load Switch Input Protection |
|---|---|
Use Scenario: Protecting 20V USB PD VBus lines from lightning-induced surges and connector hot-plug ESD. IC Role / Device Role / Timing Role: Transient diverting suppressor placed at connector entry point to clamp overvoltage before reaching PD controller and load switch. Use Value: Maintains 27.5–28V clamping across full temperature range - prevents false OVP trips and avoids need for oversized TVS with higher VC. |
Use Scenario: Safeguarding input of high-side load switches (e.g., HS2950P) in remote meters and robotics against 1kV/42Ω surges. IC Role / Device Role / Timing Role: Primary front-end protector that limits voltage seen by internal FET gate oxide and drain-source junction. Use Value: 20mΩ dynamic resistance ensures <1V additional drop during 40A surge - keeps stress within safe SOA of 30V-rated load switches. |
| IoT Device Power Rail Hardening | Notebook/Tablet DC-In Protection |
Use Scenario: Securing 12–24V DC input rails in battery-powered IoT gateways exposed to field ESD and induced surges. IC Role / Device Role / Timing Role: Single-device solution replacing multi-stage TVS+MOV networks - reduces BOM count and board area. Use Value: 1.6mm × 1.6mm DFN footprint saves >60% area vs. SOT-23 TVS - critical for space-constrained edge nodes. |
Use Scenario: Protecting 20V DC-in ports in ultrabooks and tablets from accidental adapter misconnection and ESD. IC Role / Device Role / Timing Role: Standalone EOS protector placed between barrel jack and buck converter input capacitor. Use Value: 175pF capacitance avoids resonance with typical 10–47μF input caps - no added filtering or damping required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TDS2211P | Identical electrical specs, same DFN-6 package, same marking code T22 - confirmed pin-to-pin and functional replacement per Semtech documentation. | No change in layout, routing, or thermal design - validated for USB PD and load switch use cases. | Select TDS2211P when sourcing from authorized Semtech distributors with full traceability and standard reel packaging. |
| uClamp2411ZA | 24V working voltage, lower 20A IPP rating, 0.25pF capacitance - optimized for CC/SBU lines, not power rails. | Not suitable for VBus protection due to lower surge rating and higher clamping (~33V at 20A). | Choose uClamp2411ZA only for low-capacitance data-line protection; not a functional substitute for SC185QULTRT's power-rail role. |
Compared with SC185QULTRT, TDS2211P offers identical performance and drop-in compatibility, while uClamp2411ZA serves a different signal-integrity-critical function and cannot replace SC185QULTRT in 22V power rail protection.
Availability
SC185QULTRT is available at Aetrix Electronics and suitable for USB Type-C power delivery systems, industrial load switch inputs, and IoT device DC power rails requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for SC185QULTRT 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 SC185QULTRT belongs to Semtech's Transient Diverting Suppressor (TDS) product line, engineered to replace conventional TVS diodes in high-voltage, high-energy EOS protection applications where stable clamping and temperature resilience are critical.
FAQ
What is the maximum operating temperature for SC185QULTRT?
The SC185QULTRT supports continuous operation from −40°C to +125°C ambient temperature. Its clamping voltage remains stable across this full range, with no derating required up to 125°C - confirmed by characterization data showing ≤0.5V variation in VC from −40°C to +125°C at 40A.
Does SC185QULTRT require a thermal pad on the PCB?
No, SC185QULTRT does not require a thermal pad. Energy dissipation occurs primarily in the FET channel, not the silicon junction, so no dedicated thermal land is needed. The DFN package relies on low-inductance GND connections (pins 1–3) and short IN traces (pins 4–6) for optimal surge handling - per Semtech's layout guidelines.
Can SC185QULTRT be used to protect USB 3.2 SuperSpeed differential pairs?
No, SC185QULTRT is not suitable for USB 3.2 SuperSpeed lines. Its 175pF junction capacitance would severely degrade signal integrity on high-speed differential paths. For those lines, Semtech recommends low-capacitance devices like RClamp3371ZC (<0.25pF); SC185QULTRT is intended exclusively for VBus and power-rail protection.
What is the reverse leakage current of SC185QULTRT at 22V?
At VRWM = 22V and TA = 25°C, SC185QULTRT exhibits reverse leakage current between 130nA and 600nA - well below 1μA. This ultra-low leakage ensures negligible standby power loss in always-on industrial and IoT applications.
Is SC185QULTRT compatible with lead-free reflow soldering profiles?
Yes, SC185QULTRT is fully compatible with standard lead-free reflow profiles (J-STD-020). Its DFN package uses lead-free terminal finish and meets JEDEC MSL-1 rating - no moisture sensitivity precautions are required prior to assembly.
SC185QULTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- -
- Package/Case:
- 16-UFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.9V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 4A
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MLPQ-UT (3x3)
SC185QULTRT FAQ
1.How can I place an order for SC185QULTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for SC185QULTRT 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 SC185QULTRT reliable?
The price and inventory of SC185QULTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC185QULTRT is usually 5 days.
3.What payment methods are accepted for SC185QULTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC185QULTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC185QULTRT?
SC185QULTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC185QULTRT 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 SC185QULTRT?
For technical support, including SC185QULTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC185QULTRT requirements.
6.How does Aetrix verify that SC185QULTRT is sourced from the original manufacturer or authorized distributors?
All SC185QULTRT 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 SC185QULTRT meets industry standards.
7.What is the process for return or replacement of SC185QULTRT?
All SC185QULTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC185QULTRT, 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 SC185QULTRT part is unused and in its original packaging.
Return procedure for SC185QULTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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