Semtech Corporation SDHN15K

Overview

SDHN15K from Semtech is a Transient Diverting Suppressor designed for high-energy EOS protection on single 22V-rated power or I/O lines, featuring ±30kV IEC 61000-4-2 ESD immunity, 40A peak pulse current (8/20μs), and stable 27.5–28V clamping across temperature and current range. It protects USB PD, Type-C VBus, and load switch inputs in industrial and portable electronics.

For engineers reviewing the SDHN15K datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, DFN-6 package layout guidance, real-world clamping behavior vs. conventional TVS, and direct alternatives for 22V bus protection with constant-voltage surge response.

Technical Context

The SDHN15K 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 standard TVS diodes, its clamping voltage remains nearly constant-27.5–28V at both 24A and 40A-due to decreasing R_DS(on) under surge conditions.

It operates from −40°C to +125°C with <20mΩ dynamic resistance, 175pF junction capacitance at 22V/1MHz, and reverse leakage under 600nA. Its functional architecture enables stable protection for high-voltage USB PD buses and load switch inputs where thermal drift and current-dependent clamping are critical failure modes.

Key Specifications

Pinout & Package

SDHN15K is housed in a RoHS-compliant, halogen-free DFN package measuring 1.6mm × 1.6mm × 0.55mm with exposed pad-less construction and UL 94V-0 molding compound. All six terminals are surface-mount; no thermal pad required as energy is dissipated within the FET structure.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDS2211P (identical part) and SMAJ22A (conventional TVS), SDHN15K delivers flat 27.5–28V clamping across 40A and −40°C to +125°C-enabling robust, temperature-insensitive protection where SMAJ22A's rising clamping risks downstream IC damage.

Availability

SDHN15K is available at Aetrix Electronics and suitable for USB Type-C power delivery systems, industrial load switch interfaces, and 22V power rail protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for SDHN15K 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 protection, sensing, and connectivity.

The SDHN15K belongs to Semtech's Transient Diverting Suppressor (TDS) family-engineered to replace conventional TVS diodes in high-reliability 20–24V power and interface protection applications demanding constant clamping and wide-temperature stability.

FAQ

What is the exact function of SDHN15K in a circuit?

The SDHN15K functions as a transient diverting suppressor that actively shunts high-energy EOS events-such as ESD, EFT, and surge-to ground using an integrated surge-rated FET. Unlike passive TVS diodes, it maintains a stable ~27.5–28V clamping voltage across its full 40A surge rating and entire −40°C to +125°C operating range, making SDHN15K ideal for protecting sensitive 22V-rated power rails and USB PD VBus lines.

Is SDHN15K pin-compatible with TDS2211P?

Yes-SDHN15K is Semtech's alternate orderable marking for the TDS2211P device. Both share identical DFN-6 package dimensions (1.6 × 1.6 × 0.55 mm), identical pin configuration (pins 1–3 = GND, pins 4–6 = IN), and identical electrical specifications including 22V working voltage, 40A peak pulse current, and 27.5–28V clamping. SDHN15K may be used as a direct replacement for TDS2211P without layout or firmware changes.

What is the maximum clamping voltage of SDHN15K under worst-case conditions?

The SDHN15K guarantees a maximum clamping voltage of 28V under worst-case conditions: 40A peak pulse current (8/20μs waveform), 2Ω source impedance, and across its full operating temperature range (−40°C to +125°C). This value is confirmed in the official datasheet's Electrical Characteristics table and remains stable due to the device's FET-based constant-clamp architecture-not rising with current or temperature like conventional TVS devices.

Can SDHN15K protect high-speed data lines like USB SS or DisplayPort?

No-SDHN15K is not intended for high-speed data line protection. With 175pF junction capacitance at 22V, it is optimized for VBus, power rails, and low-frequency control lines. For USB SuperSpeed, DP, or HDMI lanes, Semtech recommends low-capacitance TVS devices such as RClamp3371ZC (<0.25pF). SDHN15K should only be applied to the 22V power path (e.g., VBus, load switch input) where its constant-clamp performance delivers measurable system-level reliability benefits.

Does SDHN15K require a thermal pad or heatsink on the PCB?

No-SDHN15K does not require a thermal pad or external heatsink. Its DFN-6 package has no exposed thermal pad, and surge energy is dissipated internally via the low-R_DS(on) FET channel rather than a PN junction. The datasheet explicitly states "no thermal pad is needed," and layout guidelines emphasize low-inductance grounding (multiple vias to ground plane) instead of thermal management. Proper PCB placement near the protected connector and robust GND connections (all three GND pins) are the only mechanical requirements for full 40A performance.