Semtech Corporation SC21150ACSTRT

Overview

SC21150ACSTRT 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), and stable 27.5–28V clamping across temperature and current range - enabling robust USB PD and Type-C bus protection in industrial and mobile devices.

For engineers reviewing the SC21150ACSTRT datasheet, pinout, applications, or equivalent options, key selection criteria include its constant-clamp FET architecture, DFN 1.6×1.6mm 6-lead package, low 20mΩ dynamic resistance, 175pF junction capacitance at 22V, and compliance with IEC 61000-4-4/5 standards for industrial surge resilience.

Technical Context

The SC21150ACSTRT uses a surge-rated MOSFET as its primary shunt element, activated by a precision trigger circuit that senses overvoltage events above ~25V breakdown. Unlike conventional TVS diodes, its clamping voltage remains nearly flat (27.5–28V) from 24A to 40A IPP due to decreasing R_DS(on) under surge conditions.

It operates across –40°C to +125°C with <600nA reverse leakage at 22V, 175pF capacitance at 1MHz/22V, and 1120W peak pulse power handling - making it suitable for high-reliability input protection where thermal drift and voltage overshoot must be minimized.

Key Specifications

Pinout & Package

SC21150ACSTRT is housed in a Pb-free, RoHS-compliant DFN 1.6mm × 1.6mm × 0.55mm 6-lead package with exposed thermal pad (no internal thermal pad required; energy dissipated in silicon). All pins must be connected: Pins 1–3 are GND; Pins 4–6 are IN (parallel-connected for full 40A rating).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDS2211P.C, SC21150ACSTRT offers identical protection performance and package; compared with uClamp2411ZA, it provides 67% higher surge current rating, 2.5V lower clamping, and validated suitability for 22V power rail protection - making it the only viable option for high-energy industrial or USB PD bus applications.

Availability

SC21150ACSTRT is available at Aetrix Electronics and suitable for USB Power Delivery systems, industrial load switch inputs, and IoT device 22V power rails requiring stable component supply, long-term lifecycle support, and guaranteed surge immunity compliance.

Supply support for SC21150ACSTRT 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, protection, and signal integrity.

The SC21150ACSTRT belongs to Semtech's Transient Diverting Suppressor (TDS) product line, engineered specifically to replace conventional TVS diodes in high-reliability 20–24V power rail protection applications demanding flat clamping and temperature stability.

FAQ

What is the primary function of the SC21150ACSTRT in a circuit?

The SC21150ACSTRT functions as a transient diverting suppressor that shunts high-energy EOS events-such as ESD, lightning surges, and EFT bursts-to ground before they damage downstream components. It uses a precision-triggered FET to achieve stable 27.5–28V clamping across its full 40A surge rating and operating temperature range, distinguishing it from conventional TVS diodes whose clamping rises with current and temperature.

Does the SC21150ACSTRT require any external bias or control signals to operate?

No, the SC21150ACSTRT is a fully passive, self-triggering device. Its internal precision trigger circuit activates the shunt FET automatically when input voltage exceeds ~25V, requiring no external power, enable signals, or configuration. This makes SC21150ACSTRT ideal for always-on protection in USB PD, industrial, and portable applications where simplicity and reliability are critical.

Can the SC21150ACSTRT be used on high-speed data lines like USB SuperSpeed or PCIe?

No, the SC21150ACSTRT is not suitable for high-speed data lines. With 175pF junction capacitance at 22V, it would severely degrade signal integrity on differential pairs operating above ~100MHz. SC21150ACSTRT is explicitly designed for DC-coupled 22V power rails and low-frequency I/O lines - use low-capacitance TVS devices like RClamp3371ZC for USB SS or DP/DM protection instead.

How does the SC21150ACSTRT's clamping behavior differ from standard TVS diodes?

Unlike standard TVS diodes-whose clamping voltage rises linearly with peak pulse current (VC = VBR + IPP × RDYN)-the SC21150ACSTRT maintains a nearly constant 27.5–28V clamp from 24A to 40A due to its FET-based architecture and decreasing R_DS(on) under surge. This eliminates design uncertainty caused by temperature- and current-dependent clamping drift, a known limitation of pn-junction TVS devices.

What PCB layout practices are essential for optimal performance of the SC21150ACSTRT?

To ensure full 40A surge capability, all three GND pins (1–3) and all three IN pins (4–6) must be connected with short, wide traces to solid ground and protected-line planes respectively. Place SC21150ACSTRT within 3mm of the connector, use ≥3 vias per GND pin to minimize inductance, and avoid stubs or splits in the protected line path - these practices reduce parasitic impedance that could elevate clamping voltage during fast transients.