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:
Nov. 25, 2014
Filed:
Mar. 08, 2013
Qualcomm Incorporated, San Diego, CA (US);
Dongwon Seo, San Diego, CA (US);
Sang Min Lee, San Diego, CA (US);
QUALCOMM Incorporated, San Diego, CA (US);
Abstract
An N-bit digital-to-analog converter (DAC) includes N input stages each of which generates the same amount of current and includes a pair of similarly sized transistor switches responsive to differential bits. The 2−1 input stages associated with the M most significant bits of the DAC are connected in parallel and deliver their currents differentially to the DAC's current summing nodes. Each of the remaining (N−M) stages includes a resistive network that supplies a current defined by a binary weight of the stage's bit position within the DAC. The (N−M) stages deliver their currents to the current summing nodes differentially. The DAC further includes an impedance attenuator adapted to maintain the impedance of the current summing nodes and the voltage difference between the current summing nodes within a range defined by a gain of a differential amplifier disposed in the impedance attenuator.