Methods and systems for accessing memory

• US 7,630,257 B2
• Filed: 10/04/2006
• Issued: 12/08/2009
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mcadams, Hugh P., Lin, Sung-Wei, Madan, Sudhir Kumar
• Primary Examiner(s): TRAN, MICHAEL THANH
• Application Number:
  US11/543,338
• Publication Number:
  US 20080084773A1
• Time in Patent Office: 1,161 Days
• Field of Search: 365/190, 365/205
• US Class Current: 365/190
• CPC Class Codes: G11C 11/22 using ferroelectric elements
• CPC Class Codes: G11C 2207/005 Transfer gates, i.e. gates coupling the sense amplifier output to data lines, I/O lines or global bit lines
• CPC Class Codes: G11C 2207/2281 Timing of a read operation sense amplifier timing G11C7/06, G11C7/08
• CPC Class Codes: G11C 2207/229 Timing of a write operation sense amplifier timing G11C7/06, G11C7/08

Abstract

One aspect of the invention relates to a method for accessing a memory device. One embodiment relates to a method for accessing a memory device. In the method during a read operation, one data value is provided on a local IO line while complimentary local IO line that is associated with the local IO line is inactivated. During a write operation, another data value is provided on the local IO line and a complimentary data value is provided on the complimentary local IO line. Other systems and methods are also disclosed.

Claims

1. A method for accessing a memory cell in a memory device via a local IO line and a complimentary local IO line that are associated with the memory cell, comprising:

reading a data value from the memory cell by developing on the local IO line using a sense amp a voltage indicative of the data value while applying an approximately constant voltage that is independent of the data value to the complimentary local IO line; and

writing another data value to the memory cell by applying a voltage on the local IO line and concurrently applying a complimentary voltage on the complimentary local IO line;

wherein during the act of reading, the sense amp transfers the data value on the local IO line by coupling the sense amp to the local IO line while the complimentary local IO line is decoupled from the sense amp.

2. The method of claim 1, wherein the memory device is a ferro-electric memory.

3. A sensing system for a memory device, comprising:

a sensing circuit associated with a pair of complimentary local IO lines and a memory cell, wherein the sensing circuit comprises a local IO select circuit that facilitates data transfer between the pair of complimentary local IO lines and the memory cell; and

a global IO select circuit coupled to the pair of complimentary local IO lines and at least one global IO line, the global IO select circuit operable to selectively transfer data from the at least one global IO line to the complimentary local IO lines;

wherein the sensing system is configured to selectively inactivate one of the pair of complimentary local IO lines during a read operation.

4. The system of claim 3, wherein inactivating one of the pair of complimentary local IO lines comprises holding the one of the complimentary local IO lines at a constant voltage during the transfer of data between the one of the complimentary local IO lines and a corresponding global IO line.

5. The system of claim 4, wherein inactivating one of the pair of complimentary local IO lines comprises discarding any signal on the one of the complimentary local IO lines during the transfer of data between the one of the complimentary local IO lines and a corresponding global IO line.

6. The system of claim 3, wherein the memory device is a ferro-electric memory.

7. The system of claim 3, further comprising:

a sense amp connection circuit coupled to the memory cell and the sensing circuit, the sense amp connection circuit configured to selectively couple the sensing circuit to the memory cell.

8. The system of claim 3, wherein the global IO select circuit is coupled to more than one sensing circuit via the one of the complimentary local IO lines.