Semtech Corporation SC1474TSTRT

Overview

SC1474TSTRT 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), constant 27.5–28V clamping across 24–40A, and 20mΩ dynamic resistance - enabling robust USB PD and load switch input protection in space-constrained industrial and IoT systems.

For engineers reviewing the SC1474TSTRT datasheet, pinout, applications, or equivalent options, this page provides verified package mapping, functional pin roles, real-world clamping stability data, and validated alternatives for 22V bus protection where low-temperature-drift clamping and FET-based surge diversion are required.

Technical Context

The SC1474TSTRT uses a surge-rated MOSFET 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 R_DS(on) under surge conditions.

It operates with 22V reverse stand-off voltage, 27.9V max breakdown at 1mA, 175pF junction capacitance at 22V/1MHz, and <600nA leakage at VRWM - making it suitable for protecting high-speed interfaces without signal integrity degradation while maintaining low-power standby behavior.

Key Specifications

Pinout & Package

SC1474TSTRT is housed in a RoHS-compliant DFN 1.6mm × 1.6mm × 0.55mm 6-lead package with exposed thermal pad (no solder mask defined). All six terminals must be connected: pins 1–3 serve as parallel ground paths, pins 4–6 as parallel input connections to the protected line - enabling distributed current sharing and minimized parasitic inductance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDS2211P.C, SC1474TSTRT shares identical performance and form factor but may differ in reel quantity or date-code labeling; versus SP1003K, SC1474TSTRT delivers 14V lower clamping at 40A and stable voltage across temperature - critical for protecting 30V-tolerant ICs in thermally demanding environments.

Availability

SC1474TSTRT is available at Aetrix Electronics and suitable for USB Type-C PD systems, industrial load switch inputs, and IoT edge power buses requiring stable component supply, high-reliability surge immunity, and compact 1.6mm × 1.6mm footprint.

Supply support for SC1474TSTRT 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 analog and mixed-signal ICs for precision sensing, power management, and transient protection.

The SC1474TSTRT belongs to Semtech's Transient Diverting Suppressor (TDS) product line, engineered specifically to replace conventional TVS diodes in high-energy EOS applications where stable clamping voltage and temperature-invariant performance are mandatory.

FAQ

What is the maximum operating temperature for SC1474TSTRT?

The SC1474TSTRT is rated for continuous operation from −40°C to +125°C ambient temperature. Its clamping voltage remains stable across this full range - measured at 27.5–28V from −40°C to +125°C under 40A surge conditions - making it suitable for uncooled industrial and automotive under-hood environments where thermal management is limited.

Does SC1474TSTRT require a thermal pad on the PCB?

No, SC1474TSTRT does not require a thermal pad. The device dissipates surge energy through its internal FET structure rather than junction heating, and the datasheet explicitly states "no thermal pad is needed." Instead, low-inductance grounding via multiple vias to an internal ground plane is essential to handle 40A peak current without voltage overshoot.

How does SC1474TSTRT differ from standard TVS diodes in clamping behavior?

Unlike standard TVS diodes whose clamping voltage rises linearly with peak current (VC = VBR + IPP × RDYN), SC1474TSTRT uses a triggered FET shunt that maintains near-constant clamping (27.5–28V) from 24A to 40A. This eliminates the need for oversized TVS devices to meet low-clamp targets - a key advantage in USB PD and load switch protection.

Can SC1474TSTRT protect high-speed data lines like USB SS or PCIe?

No, SC1474TSTRT is not intended for high-speed data line protection. With 175pF junction capacitance, it is optimized for VBUS, power rails, and enable/control lines. For USB SuperSpeed or PCIe lanes, Semtech recommends low-capacitance devices like RClamp3371ZC (<0.25pF); SC1474TSTRT should be used only on power or low-frequency signal paths.

What is the recommended PCB layout for SC1474TSTRT?

Place SC1474TSTRT as close as possible to the protected connector. Connect all three GND pins (1–3) to a solid ground plane using ≥3 vias each, and tie all three IN pins (4–6) together with a short, wide trace to the protected line. Avoid stubs or splits - the goal is minimal loop inductance to preserve 40A surge capability and fast response to sub-nanosecond ESD events.