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:
Jan. 22, 1985
Filed:
Dec. 28, 1981
Douglas P Sheppard, Grapevine, TX (US);
Mostek Corporation, Carrollton, TX (US);
Abstract
A read only memory circuit (10) includes an array of memory transistors including a row of such transistors (12-28) connected to a common word line (30). For each column of memory transistors there is provided a set of reference transistors which receive a word line signal which is concurrent with any word line signal provided to any word line in the memory array. Column decode signals (CD1-CD4) are provided to select a memory transistor on an activated word line and to select corresponding reference transistors. The memory transistor is fabricated to have one of a plurality of threshold voltages. The reference transistors are fabricated to have different predetermined threshold voltages. The drive signals are applied through the word lines concurrently to the selected memory transistor and corresponding reference transistors to cause the transistors to transition from a first state to a second state. Decoding circuitry is provided to determine the time sequence of transition of the memory transistor relative to the reference transistors. This decoding produces an output signal which corresponds to the threshold voltage and therefore the data state for the selected memory transistor.