The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 2005
Filed:
Sep. 23, 2003
Ramin Khoini-poorfard, Austin, TX (US);
Douglas R. Frey, Bethlehem, PA (US);
Ramin Khoini-Poorfard, Austin, TX (US);
Douglas R. Frey, Bethlehem, PA (US);
Silicon Laboratories, Inc., Austin, TX (US);
Abstract
A digital-to-analog converter circuit for a subscriber line analog front end includes a differential amplifier, switch circuitry, and first and second current steering digital-to-analog converters (DAC), each DAC having a first and second output forming a differential DAC output. The switch circuitry couples the differential output of at most a selected one of the first and second DACs to a pair of switch nodes. When the differential output of the selected DAC is coupled to the pair of switch nodes, the differential output of the other DAC is shorted. A differential input of the differential amplifier is communicatively coupled to the pair of switch nodes. A differential output of the differential amplifier is coupled to drive a tip line and a ring line of a subscriber line. In various embodiments, the DACs, switch circuitry, and differential amplifier reside on the same semiconductor substrate.