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, 1988
Filed:
May. 19, 1986
John M Wynne, Dooradoyle, IE;
Analog Devices, Inc., Norwood, MA (US);
Abstract
A four-quadrant multiplier uses a CMOS digital-to-analog converter (DAC) and just one operational amplifier. The back gates of the CMOS switches in the DAC are biased in the 'off' condition during a substantial voltage swing at the output of the DAC. In one embodiment, the back gates of the CMOS switches are held at about -5 V with respect to the output lines, and the logic low level to the off switch also is set at -5 V relative to the output lines. The DAC connections are 'reversed' so as to receive the analog input across the terminals intended as the DAC's output, with the inputs of the operational amplifier being connected across the reference voltage terminal and a feedback or output terminal of the DAC.