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:
Jul. 03, 1990
Filed:
Jan. 06, 1989
Timothy Coe, Oxnard, CA (US);
Vitesse Semiconductor Corporation, Camarillo, CA (US);
Abstract
An integrated circuit, having applicability to GaAs circuitry, is disclosed for performing a current steering logic function. The integrated circuit comprises a switching circuit, a high impedance tail current source, and a pair of low impedances respectfully coupled to the tail current source through a respective one of the switching transistors. The resistors in the tail current source and in the load resistance are formed from sheet resistor material so that any process-induced variation in the resistivity of the sheet material causes a mutual but compensatory variation in both the load and current source resistors, maintaining a match between the current capability of the current source and the resistance of the loads. The follower circuit, on the other hand, comprises a low impedance FET and a follower current source having an active load whose current is primarily dependent on its threshold voltage. Accordingly, process factors which affect the threshold voltage of the low impedance FET also affect the threshold voltage of the active load in a mutually compensatory manner without adversely affecting the output levels of the logic level signals from the current steering circuit.