US5652724A
Expired / Lapsed
US
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Burst EDO memory device having pipelined output buffer
Assignee: Round Rock Research LLC
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Filing: 1995-02-10
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Granted: 1997-07-29
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Expires: 2015-02-10
Abstract
Abstract An integrated circuit memory device is designed for high speed data access and for compatibility with existing memory systems. An address strobe signal is used to latch a first address. During a burst access cycle the address is incremented internal to the device with additional address strobe transitions. A new memory address is only required at the beginning of each burst access. Read/Write commands are issued once per burst access eliminating the need to toggle the Read/Write control line at the device cycle frequency. Transitions of the Read/Write control line during a burst access will terminate the burst access, reset the burst length counter and initialize the device for another burst access. A two stage pipelined output buffer latches read data in a first stage while data from a second stage is driven from the device. Internal read lines may become invalid in preparation for additional access cycles after the data is latched in the first stage. The device is compatible with existing Extended Data Out DRAM device pinouts, Fast Page Mode and Extended Data Out Single In-Line Memory Module pinouts, and other memory circuit designs.
Inventors
- 👤 Troy A. Manning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:46
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/06; G06F12/0638; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/4063; G11C11/407; G11C7/00; G11C7/10; G11C7/1015; G11C7/1018; G11C7/1021; G11C7/1024; G11C7/1039; G11C7/1045; G11C7/1078; G11C7/109; G11C7/1096; G06F2212/00; G06F2212/20; G06F2212/202; G06F2212/2022
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
127 words
A circuit to drive an output data signal from a memory device, comprising: an output driver circuit having a driver control input; and a latch adapted to receive a latch control signal and a clear signal; said latch further adapted to receive an internal data signal and drive the driver control input in response to a first state of the latch control signal despite transitions of the clear signal; said latch further adapted to store the internal data signal and drive the driver control input in response to a second state of the latch control signal and a first state of the clear signal; said latch being cleared in response to the second state of the latch control signal and a second state of the clear signal.
Claim 2
Dependent Claim
127 words
A circuit to drive an output data signal from a memory device, comprising: an output driver circuit having a driver control input; and a latch adapted to receive a latch control signal and a clear signal; said latch further adapted to receive an internal data signal and drive the driver control input in response to a first state of the latch control signal despite transitions of the clear signal; said latch further adapted to store the internal data signal and drive the driver control input in response to a second state of the latch control signal and a first state of the clear signal; said latch being cleared in response to the second state of the latch control signal and a second state of the clear signal.
Claim 3
Dependent Claim
23 words
The circuit of claim 1, wherein the clear control signal clears said latch between cycles in a burst access of the memory device.
Claim 4
Dependent Claim
190 words
A circuit to drive an output data signal from a memory device, comprising: an output driver circuit having a driver control input; and a latch adapted to receive a latch control signal and a clear signal, said latch further adapted to receive an internal data signal and drive the driver control input in response to a first state of the latch control signal, said latch further adapted to store the internal data signal and drive the driver control input in response to a second state of the latch control signal and a first state of the clear signal, said latch being cleared in response to the second state of the latch control signal and a second state of the clear signal, an output feedback switching circuit to feed the driver control input back to an input of said latch, when the latch control signal is in the second state, to form said latch; and an internal data switching circuit to isolate the internal data signal from the input of said latch when said output feedback switching circuit is feeding the driver control input back to the input of said latch.
Claim 5
Dependent Claim
190 words
A circuit to drive an output data signal from a memory device, comprising: an output driver circuit having a driver control input; and a latch adapted to receive a latch control signal and a clear signal, said latch further adapted to receive an internal data signal and drive the driver control input in response to a first state of the latch control signal, said latch further adapted to store the internal data signal and drive the driver control input in response to a second state of the latch control signal and a first state of the clear signal, said latch being cleared in response to the second state of the latch control signal and a second state of the clear signal, an output feedback switching circuit to feed the driver control input back to an input of said latch, when the latch control signal is in the second state, to form said latch; and an internal data switching circuit to isolate the internal data signal from the input of said latch when said output feedback switching circuit is feeding the driver control input back to the input of said latch.
Claim 6
Dependent Claim
26 words
The circuit of claim 3, wherein said latch after being cleared, remains cleared until the internal data signal is presented on the input of said latch.
Claim 7
Dependent Claim
24 words
The circuit of claim 1, wherein said output driver circuit provides a high impedance output from the memory device when said latch is cleared.
Claim 8
Dependent Claim
30 words
The circuit of claim 1, wherein said latch after being cleared, remains cleared while the latch control signal is in the second state, despite transitions of the clear control signal.
Claim 9
Dependent Claim
36 words
The circuit of claim 1, wherein the first state of the latch control signal is a low voltage level, and the first state of the first state of the clear signal is a high voltage level.
Claim 10
Dependent Claim
54 words
The circuit of claim 1, wherein the latch comprises: a feedback circuit coupled to the driver control input and the latch control signal; and switching circuitry connected to the feedback circuit and the latch control signal for coupling a feedback signal to the input of the latch in response to the latch control signal.
Claim 11
Dependent Claim
39 words
The circuit of claim 8 wherein the feedback circuit comprises a NOR gate having a first input coupled to the driver control input, a second input connected to the clear signal, and an output connected to the switching circuity.
Claim 12
Dependent Claim
30 words
The circuit of claim 1, wherein the output driver circuit comprises: a driver transistor having a gate connected to the driver control input and a drain connected to an output.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-28 | 2001-01-27 | 2001-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-28 | 2005-01-27 | 2005-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-28 | 2009-01-27 | 2009-07-29 | $7700.00 | Window Closed / Lapsed |