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. 04, 1996
Filed:
May. 12, 1995
James R Butler, San Jose, CA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A double-folded cascode operational amplifier capable of operating with rail-to-rail common mode inputs includes two differential input transistor pairs of opposite conductivity, with an associated current source and input resistor pair for each pair of input transistors. Its gain stage includes two interconnected pairs of folded cascode gain transistors that are connected to the two pairs of input resistors so that a change in the differential input signal produces a corresponding change in the gain stage output via the resistors. An output stage includes transistor-resistor circuitry to bias a pair of output transistors in opposite directions and produce a net amplifier output at their junction. The gain transistor voltages are balanced by a voltage shifting circuit to inhibit input voltage offsets.