Semtech Corporation SC431LI5SK-1TRT

Overview

SC431LI5SK-1TRT from Semtech is a Transient Diverting Suppressor (TDS) designed for high-energy EOS protection of 22V-rated power or I/O lines. It delivers ±30kV IEC 61000-4-2 ESD immunity, 40A peak pulse current (8/20μs), 27.5–28V clamping at 24–40A, 20mΩ dynamic resistance, and 175pF junction capacitance in a DFN 1.6×1.6×0.55mm 6-lead package - deployed in USB Type-C PD input protection.

For engineers reviewing the SC431LI5SK-1TRT datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage stability across temperature and current, low dynamic resistance for flat VC response, DFN board-space efficiency, and compatibility with 22V bus systems requiring industrial surge compliance (±1kV, 1.2/50μs + 8/20μs).

Technical Context

The SC431LI5SK-1TRT 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) from 24A to 40A due to decreasing R_DS(on) under surge conditions.

It operates over –40°C to +125°C, maintains stable clamping across temperature (±0.5V variation), and achieves 1120W peak pulse power handling. Its 175pF capacitance at 22V/1MHz and 130–600nA reverse leakage support high-speed interface protection without signal integrity degradation.

Key Specifications

Pinout & Package

SC431LI5SK-1TRT is housed in a Pb-free, RoHS-compliant DFN 1.6mm × 1.6mm × 0.55mm 6-lead package with exposed thermal pad (no solder connection required). All pins must be connected - three GND pins (1–3) and three IN pins (4–6) - to achieve rated 40A surge performance and minimize parasitic inductance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDS2211P.C (identical part) and SP1003-02HTG (low-C TVS), SC431LI5SK-1TRT uniquely delivers flat 27.5–28V clamping across 24–40A and temperature, enabling reliable 22V bus protection where conventional TVS devices fail to meet voltage margin requirements.

Availability

SC431LI5SK-1TRT is available at Aetrix Electronics and suitable for USB Type-C PD interfaces, industrial load switch inputs, IoT edge device power buses, and storage device 22V rails requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for SC431LI5SK-1TRT 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 signal integrity.

The SC431LI5SK-1TRT belongs to Semtech's Transient Diverting Suppressor (TDS) family, engineered to replace conventional TVS diodes in high-energy EOS applications demanding stable clamping, wide temperature operation, and compact footprint.

FAQ

What is the primary protection function of the SC431LI5SK-1TRT?

The SC431LI5SK-1TRT functions as a Transient Diverting Suppressor (TDS) that actively shunts high-energy EOS events - including ESD, EFT, and lightning surges - away from sensitive downstream components. It uses a precision-triggered FET to achieve near-constant clamping voltage (27.5–28V) across its full 40A surge rating, distinguishing it from passive TVS diodes whose clamping rises linearly with current. This behavior makes SC431LI5SK-1TRT especially effective for protecting 22V power rails in USB PD and industrial systems.

Does the SC431LI5SK-1TRT require a thermal pad or heatsink on the PCB?

No, the SC431LI5SK-1TRT does not require a thermal pad or external heatsink. Its DFN package dissipates surge energy internally through the FET channel, and the datasheet explicitly states "no thermal pad is needed" under transient conditions. Instead, optimal performance relies on low-inductance grounding: all three GND pins (1–3) must connect directly to the PCB ground plane using multiple vias, and all three IN pins (4–6) must be shorted together with minimal trace length - design practices confirmed in the official SC431LI5SK-1TRT layout guidelines.

Can the SC431LI5SK-1TRT be used to protect high-speed data lines like USB SuperSpeed or PCIe?

No, the SC431LI5SK-1TRT is not intended for high-speed data line protection. With 175pF junction capacitance at 22V, it is optimized for 22V power rail or low-frequency I/O protection (e.g., VBUS, CC, SBU, or load switch inputs), not signal integrity-critical paths. For USB SuperSpeed, DP/DM, or PCIe lanes, Semtech recommends low-capacitance TVS devices such as RClamp3371ZC (<0.25pF). Using SC431LI5SK-1TRT on such lines would severely degrade signal rise/fall times and cause bit errors.

How does the SC431LI5SK-1TRT compare to standard TVS diodes in terms of temperature performance?

The SC431LI5SK-1TRT maintains clamping voltage within ±0.5V from –40°C to +125°C, whereas conventional TVS diodes exhibit significant positive temperature coefficient - clamping voltage increases by ~0.1V/°C, exceeding safe margins at elevated temperatures. For example, a typical 22V TVS may clamp at ~38V at 125°C and 24A, while SC431LI5SK-1TRT holds steady at ~27.5V. This stability eliminates thermal derating calculations and ensures consistent protection across industrial operating ranges - a verified characteristic documented in the SC431LI5SK-1TRT's clamping vs. temperature curves.

Is the SC431LI5SK-1TRT compatible with automated SMT assembly processes?

Yes, the SC431LI5SK-1TRT is fully compatible with standard SMT reflow processes. Its DFN 1.6×1.6mm package meets IPC-7351B land pattern recommendations, uses lead-free (Pb-free) terminations, and is rated for peak reflow temperatures up to 260°C per J-STD-020. The device is supplied in 7-inch tape-and-reel format (3,000 units/reel) with industry-standard sprocket hole pitch and orientation - verified in Semtech's official ordering information and packaging drawings for SC431LI5SK-1TRT.