Semtech launches 48V USB-C protection device for PD 3.1

Semtech has introduced the TDS5311P protection device for 48V USB Power Delivery systems, targeting USB PD 3.1 Extended Power Range designs that use USB Type-C connections.

The launch comes as USB Type-C is used for higher power levels in devices ranging from laptops to industrial systems. USB PD 3.1 supports up to 48V and 240W over a single cable.

The new device is designed to protect the VBUS line, the pin in a USB Type-C connector that carries supply voltage to downstream equipment. That line can be exposed to electrical overstress events, including electrostatic discharge, electrical fast transients, cable discharge events, and surge transients linked to lightning or power distribution switching.

As voltage levels rise, protection becomes harder to manage with conventional transient voltage suppression diodes. Higher VBUS voltages require higher clamping voltages in many existing designs, which can force engineers to use downstream components with higher voltage ratings and more board space.

Protection shift

The TDS5311P is based on Semtech's SurgeSwitch design, which uses a MOSFET-based topology rather than the PN junction approach common in standard TVS diodes. According to Semtech, this allows the device to keep clamping voltage nearly constant across the surge current range and over operating temperatures.

For the new part, Semtech listed a working voltage of 53V, a minimum reverse breakdown voltage of 57V, peak pulse current of 24A, and a clamping voltage of 63V at peak pulse current. It also gave a dynamic resistance of 31mΩ.

Semtech compared that 63V clamping voltage with about 87V for a conventional TVS option used in some 48V USB PD applications under similar test conditions. The roughly 24V difference could let system designers choose downstream parts with lower voltage tolerance requirements.

Semtech also cited compliance figures tied to common immunity standards. The device is rated for electrostatic discharge at +/-20kV contact and +/-25kV air under IEC 61000-4-2, electrical fast transients at +/-4kV under IEC 61000-4-4, and surge performance of 24A for an 8/20μs waveform and 1kV for a 1.2/50μs waveform under IEC 61000-4-5.

Target uses

The product is aimed at systems using the 48V operating mode introduced under USB PD 3.1 Extended Power Range. In those systems, the protection device is placed in parallel with the VBUS rail at the USB Type-C port entry point, diverting transient energy to ground while normal operation continues.

Semtech identified several application areas, including AI laptops and other computing devices drawing higher wattage over USB-C, docking stations that supply multiple downstream devices, portable power stations and power banks, and industrial embedded computing platforms exposed to electrically noisy environments.

The broader commercial backdrop is the growing use of USB Type-C as both a data and power interface. As manufacturers push more power through the connector, component selection around the input stage is becoming more important because overstress on the VBUS line can damage power management integrated circuits and charging circuitry.

That issue is particularly relevant in industrial and computing equipment, where exposure to transient events may be greater and repair costs can be high. Protection components that reduce the peak voltage seen by downstream circuits can affect both product reliability and the specification of adjacent parts.

Design pressure

Conventional TVS diodes remain widely used in board-level protection, but their clamping voltage typically rises with surge current and can increase further with temperature. As a result, worst-case protection behavior can occur under the same conditions when stress on the system is highest.

By contrast, Semtech's pitch for the TDS5311P rests on a steadier clamping profile at the higher voltage levels now appearing in USB power designs. The company said the lower clamping level can increase design margin while reducing the need to over-specify downstream components.

The release adds to a growing set of products tied to the shift from earlier 20V, 100W USB power delivery levels to 28V, 36V, and 48V options under the latest standard. With those changes, power-line protection has become a more visible part of USB Type-C hardware design, particularly in products expected to handle up to 240W.

Semtech describes the TDS5311P as purpose-built for 48V VBUS protection in USB PD 3.1 EPR systems.