Low power static memory

• US 6,529,402 B1
• Filed: 03/08/2002
• Issued: 03/04/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Andersen, John E., Hsu, Louis Lu-Chen, Wang, Li-Kong
• Primary Examiner(s): Lam, David
• Application Number:
  US10/094,533
• Time in Patent Office: 361 Days
• Field of Search: 365/154, 365/230.03, 365/189.01, 365/189.05, 365/230.04, 365/189.09, 365/205
• US Class Current: 365/154
• CPC Class Codes: G11C 11/417 for memory cells of the field-effect type
• CPC Class Codes: G11C 5/025 Geometric lay-out considerations of storage- and peripheral-blocks in a semiconductor storage device geometrical lay-out of the components in integrated circuits, H01L27/0207
• CPC Class Codes: G11C 8/08 Word line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, for word lines

Abstract

A stacked block array architecture.for a SRAM memory for low power applications. The architecture turns on only the required data cells and sensing circuitry to access a particular set of data cells of interest. The wordline delay is reduced by using a shorter and wider wordline wire size. Although less power is consumed, the performance is improved by the reduction in loading of wordlines and bitlines.

Claims

1. A low power static random access memory SRAM architecture comprising:

the SRAM comprises a memory array which is divided into a plurality of memory subarrays;

a sense amplifier is provided for each column, having a pair of bitlines, of each memory subarray, and wherein a separate sense amplifier is provided for each column of data cells in each memory subarray, and each sense amplifier is not shared between different subarrays, such that when a set of memory cells in a memory subarray is accessed in a data read or write operation, only the memory subarray and the set of memory cells and sense circuits of interest are accessed and activated in the data read or write operation, to reduce power consumption during each data read or write operation.

2. The SRAM architecture of claim 1, wherein each subarray has 128 wordlines.

3. The SRAM architecture of claim 1, comprising a stacked row memory architecture wherein each wordline serves two adjacent rows of memory cells, and each of two adjacent memory cells served by the same wordline is served by a separate sense amplifier.

4. The SRAM architecture of claim 3, wherein each wordline comprises a short and wide conductor.

5. The SRAM architecture of claim 3, wherein bitline pairs are interleaved to accommodate a sense amplifier placed at each end of each subarray.

6. The SRAM architecture of claim 3, wherein sense amplifiers are laid out at both the top and bottom of each column of each subarray, and each sense amplifier senses one half of the number of memory cells in each column.

7. The SRAM architecture of claim 1, wherein the data is sent out of and read into the memory blocks in a pipeline manner in order to widen the width of each data line.

8. The SRAM architecture of claim 1, wherein the layout of each sense amplifier uses a two column pitch sense amplifier design.