Fingerprint sensor package having enhanced electrostatic discharge protection and associated methods

Abstract

A fingerprint sensor package includes a fingerprint sensing integrated circuit within a housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto. At least one external electrode is carried by the housing for finger contact. An electrostatic discharge (ESD) circuit is provided within the housing and is connected to the at least one external electrode. An isolation circuit is connected to the at least one line of the processing circuitry for external connection. The external electrode and ESD circuit, as well as the line isolation circuit protect the integrated circuit against damage by voltage transients, such as ESD. The at least one external electrode may include first and second external electrodes. The first electrode may be connected to the electrostatic discharge circuit. The processing circuit may further comprise a wake-up circuit for selectively powering predetermined circuit portions responsive to sensing finger contact with the second external electrode. Moreover, the housing may define a recess therein to guide a finger of a user along a predetermined path of travel to contact the first external electrode before the second external electrode.