This application report discusses a high-power four-pair solution for Power-over-Ethernet (PoE) applications requiring power in excess as defined in the current IEEE 802.3at standard. Specifically, this report provides a dual TPS2378-based, forced four-pair solution providing 45 W to the load.

This application note covers the fundamentals of Touch-on-Metal (ToM) technology using an LDC1612 Inductance-to-Digital Converter (LDC) and provides guidance for constructing ToM buttons. Simple on and off buttons can be easily implemented using inductive sensing. Additionally, by using a high resolution LDC, microscopic movements in a flat metal button can be sensed and processed to determine how hard a given button was pressed. This approach allows reuse of existing metal surfaces commonly found in many applications such as consumer electronics and appliances.

This report contains a design example for a multi-button brushed aluminum panel and provides guidance on the mechanical system and sensor design, as well as measured performance results of the complete system.

This application note describes the operating conditions over which the VELVDD and VELVSS outputs of the TPS65633 can support output currents up to 500 mA.