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:
Aug. 29, 1995
Filed:
Dec. 02, 1993
Todd L Brooks, Boston, MA (US);
Motorola Inc., Schaumburg, IL (US);
Abstract
A current-mode DAC (20) includes two sub-DACs (22, 36), and a calibrated attenuator (48). One sub-DAC (22) receives least-significant-bits (LSB) of a K-bit digital input signal, and the second sub-DAC (36) receives most-significant-bits (MSB) of the K-bit digital input signal. An output of the sub-DAC (22) is attenuated by an attenuator (50), and the attenuated signal is summed with an output of the second sub-DAC (36) to form an analog output signal. A 4-phase gain adjust sample and hold circuit (49) is used to calibrate the attenuator (50). The 4-phase gain adjust sample and hold circuit (49) samples the current from the attenuator (50), and removes device mismatch effects in the attenuator (50) which cause linearity errors in the current-mode DAC (20).