1.5mΩ 48V automotive load switch

Infineon has revealed a 1.5mΩ protected load switch for 24V and 48V automotive systems.

“With more than 1,000,000 switching cycles, the switches far exceed the average of conventional relays,” claimed Infineon.

Infineon BTH50015-1LUA automotive load switch app

Called BTH50015-1LUA, it is functional across 12 to 54V, will work from 8 to 60V with some restrictions, and can survive over -0.3 to +70V.


1.5mΩ is a typical 25°C on-resistance, which rises to 2.9mΩ (3.5mΩ max) at the maximum operating temperature of 150°C.


Junction to case thermal resistance of the 9.8 x 11.7mm surface-mount package is 0.4°C/W.

Minimum nominal load current is 32A (85°C ambient, four-layer PCB).

Logic inputs are compatible with 3.3 and 5V logic levels, can be tied to the positive power lines, and will survive -75V.

On the power side, protections include short-circuit, over-current and over-temperature.

“Diagnostic signals enable advanced fault detection and increase the reliability of the entire vehicle by preventing failure modes in the power supply network,” according to the company. “The accuracy of the load current sense is ±5% after calibration and can be easily determined by reading an analog voltage at the IS pin.”

It comes with a safety application note that supports the evaluation of hardware elements according to ISO 26262, added Infineon.

Infineon automotive load switch Arduono dev board

A similar part, BTH50030-1LUA, has a 3mΩ typical 25°C on-resistance, and a 6mΩ variant is in the pipeline.

Find the 1.5mΩ BTH50015-1LUA on this Infineon web page, and an Arduino-compatible development board is available.

Steve Bush

Steve Bush is the long-standing technology editor for Electronics Weekly, covering electronics developments for more than 25 years. He has a particular interest in the Power and Embedded areas of the industry. He also writes for the Engineer In Wonderland blog, covering 3D printing, CNC machines and miscellaneous other engineering matters.

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