Integrated Schottky logic read only memory
AssigneeHoneywell Inc.
InventorJeffrey P. Graebel
Life of this patent
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Abstract
An integrated Schottky logic (ISL) read only memory (ROM) uses ISL drivers and decoders connected to wordlines and data bitlines. The pattern of data stored in the ISL is determined by Schottky diodes which are connected between selected data bitlines and wordlines. Improved performance is achieved by using a leakage current compensation source (such as a wordline pullup resistor) connected to each wordline, and by using a programmable dummy load (such as one or more dummy bitlines). The pullup resistors compensate for bitline loading sensitivity caused by leakage currents of the workline drivers. The dummy bitlines are selectively connected to those wordlines which are lightly loaded to compensate for wordline loading sensitivity and thus equalize access time and improve wordline decoder noise margins.
Claims23
A read-only memory (ROM) device comprising:
- a plurality of wordlines;
- a plurality of data bitlines;
- diodes selectively connected between wordlines and data bitlines to represent a predetermined data pattern based upon presence and absence of a diode connected between each wordline and data bitline;
- wordline driver means for addressing a selected wordline;
- output means for deriving output signals representative of the data pattern based upon signals received from the data bitlines as the selected wordline is addressed;
- and
- pattern sensitivity compensation means connected to the wordlines for compensating for variations of loading due to the predetermined data pattern.
An integrated Schottky logic (ISL) read only memory (ROM) device comprising:
- a plurality of wordlines;
- a plurality of data bitlines;
- a current source connected to each data bitline;
- a wordline driver connected to each wordline;
- a sense amp connected to each data bitline;
- an array of Schottky diodes connected between wordlines and data bitlines to represent a predtermined data pattern based upon presence and absence of a Schottky diode connected between each wordline and data bitline;
- and
- pattern sensitivity compensation means connected to the wordlines for compensating for variation of loading due to the predetermined data pattern.
Dependencies are inferred from the claim text.