Semtech Corporation SC632ULTRT

Overview

SC632ULTRT from Semtech is a Transient Diverting Suppressor designed to protect 22V-rated I/O or power lines against EOS, ESD, and surge events. It delivers ±30kV IEC 61000-4-2 ESD immunity, 40A peak pulse current (8/20μs), and stable 27.5–28V clamping across temperature and current range. Used in USB Type-C PD input protection and load switch front-end safeguarding.

For engineers reviewing the SC632ULTRT 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 industrial and portable power delivery systems requiring robust EOS resilience.

Technical Context

The SC632ULTRT uses a surge-rated FET as its primary protection element, activated by a precision trigger circuit that senses overvoltage and rapidly shunts transient energy to ground. Unlike conventional TVS diodes, its clamping voltage remains nearly constant due to ultra-low dynamic resistance (20mΩ) and decreasing R_DS(on) under increasing current.

It operates across –40°C to +125°C, maintains ≤600nA reverse leakage at 22V, and achieves stable 27.5–28V clamping at both 24A and 40A (1.2/50μs + 8/20μs combination waveform, R_S = 2Ω), enabling reliable protection in thermally demanding environments without derating.

Key Specifications

Pinout & Package

SC632ULTRT is housed in a RoHS-compliant, halogen-free DFN-6 package (1.6mm × 1.6mm × 0.55mm) with UL 94V-0 molding compound and lead-free finish. All six terminals are required for full 40A surge rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient suppression applications.

Compared with TDS2211P (identical spec), SC632ULTRT offers seamless supply continuity; versus uClamp2411ZA, it provides 2× peak current capacity and 2V lower clamping-critical for protecting 22V-rated power management ICs without overvoltage risk.

Availability

SC632ULTRT is available at Aetrix Electronics and suitable for USB Type-C PD interfaces, industrial load switch inputs, and IoT 22V power rail protection requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SC632ULTRT 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 precision sensing, protection, and connectivity.

The SC632ULTRT belongs to Semtech's Transient Diverting Suppressor (TDS) family, engineered to replace conventional TVS diodes in high-energy EOS applications where stable clamping and temperature independence are critical.

FAQ

What is the clamping voltage of SC632ULTRT at 40A surge current?

The SC632ULTRT clamps at 27.6–28V under 40A peak pulse current (1.2/50μs voltage + 8/20μs current combination waveform, R_S = 2Ω). This value is guaranteed across –40°C to +125°C and reflects its FET-based architecture, which maintains stable voltage by reducing R_DS(on) as current rises - unlike TVS diodes whose clamping increases linearly with current.

Is SC632ULTRT pin-compatible with standard TVS diodes in DFN-6 packages?

No - SC632ULTRT uses a unique 3-pin input / 3-pin ground configuration (pins 4–6 = IN, pins 1–3 = GND), requiring dedicated PCB layout. Standard unidirectional TVS diodes in DFN-6 typically use anode/cathode/gnd or bidirectional dual-channel arrangements. Layout must connect all three IN pins in parallel and all three GND pins to a low-inductance plane to achieve rated 40A performance.

Can SC632ULTRT be used to protect 24V industrial control inputs?

SC632ULTRT is rated for 22V working voltage and 27.5–28V clamping - using it on a 24V nominal bus risks sustained conduction and thermal failure. For 24V systems, Semtech's SC633ULTRT (24V-rated TDS) or uClamp2411ZA (24V, lower IPP) are appropriate alternatives. SC632ULTRT must only be applied where maximum steady-state voltage does not exceed 22V.

What is the junction capacitance of SC632ULTRT and how does it affect circuit design?

SC632ULTRT exhibits 175pF junction capacitance at 22V and 1MHz. This value is low enough for 22V power rail protection without impacting switching regulator stability or causing excessive AC loading, but too high for high-speed data lines (e.g., USB SS, PCIe). It should be placed on power inputs or low-frequency control signals - never on differential pairs or RF paths where sub-1pF capacitance is required.

Does SC632ULTRT require external components like series resistors or RC filters for optimal operation?

No - SC632ULTRT is a self-contained, single-chip solution requiring no external components. Its integrated trigger circuit and shunt FET eliminate the need for timing resistors or gate drive networks. Optimal performance depends solely on proper PCB layout: shortest possible trace from connector to SC632ULTRT IN pins, direct connection of all three GND pins to a solid ground plane via multiple vias, and placement within 5mm of the protected interface.