# US 5,703,822 A · Serial access memory device including memory sections having different latencies

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- Number: US 5,703,822 A
- Document ID: US5703822A
- Status: Granted
- Kind: A
- Application number: 08/788,077
- Filed: 1997-01-22
- Granted: 1997-12-30
- Earliest claimed: 1996-01-23
- Assignees: NEC Corporation
- Inventors: Hiroaki Ikeda
- Web page: https://patentgrep.com/patent/US5703822A

## CPC

- G11C 7/1072: {for memories with random access ports synchronised on clock signal pulse trains, e.g. synchronous memories, self timed memories}
- G11C 7/1018: {Serial bit line access mode, e.g. using bit line address shift registers, bit line address counters, bit line burst counters}
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

In a serial access memory device, a first memory section divided into a plurality of first segments and a second memory section divided into a plurality of second segments are provided. A first latency of the first memory section is shorter than a second latency of the second memory section. The serial accesses of segments of the first and second memory sections are simultaneously initiated. The serial access of segments of the first memory section is completed within a time period corresponding to the second latency.

## Claims

### Claim 1

A serial access memory device comprising:
a first memory section divided into a plurality of first segments and having a first latency;
a second memory section divided into a plurality of second segments and having a second latency longer than said first latency;
first addressing means, connected to said first memory section, for sequentially generating first addresses to access the first segments of said first memory section;
second addressing means, connected to said second memory section, for sequentially generating second addresses to access the second segments of said second memory section; and
control means, connected to said first and second addressing means, for simultaneously initiating operations of said first and second addressing means and completing the operation of said first addressing means within a time period corresponding to said second latency.

### Claim 2 (depends on 1)

The device as set forth in claim 1, further comprising:
a third memory section divided into a plurality of third segments and having a third latency shorter than said first latency; and
third addressing means, connected to said third memory section, for sequentially generating third addresses to access the third segments of said third memory section,
said control means, further connected to said third addressing means, for initiating an operation of said third addressing means simultaneously with the operations of said first and second addressing means and completing the operation of said third addressing means within a time period corresponding to said first latency.

### Claim 3 (depends on 1)

The device as set forth in claim 1, further comprising an input/output buffer connected to said first and second memory sections.

### Claim 4 (depends on 2)

The device as set forth in claim 2, further comprising an input/output buffer connected to said first, second and third memory sections.

### Claim 5 (depends on 1)

The device as set forth in claim 1, wherein row components of said first addresses are the same as row components of said second addresses.

### Claim 6 (depends on 2)

The device as set forth in claim 2, wherein row components of said first addresses and row components of said second addresses are the same as said third addresses.

### Claim 7 (depends on 1)

The device as set forth in claim 1, wherein said first memory section has an SRAM configuration, and said second memory section has a DRAM configuration.