POSFET touch sensing transducers: Interface electronics design methodology based on the transconductance-to-drain-current efficiency gm/ID

A design space map shows confidence regions where the specifications such as touch sensing device gain, current consumption and source resistance value are met. The design methodology enables to push the performance of the POSFET by selecting the most appropriate bias resistance value and it reduces time-consuming iterations which are normally required. As a proof of concept of the proposed methodology, measurements as well as a design example are presented.