Memory device with adaptive sense unit and method of reading a cell array

US7489563B2 · kind B2 · utility

Assignee

• Qimonda Flash GmbH & Co. KG · DE

Inventors

• Detlev Richter · Unterhaching, DE
• Mirko Reissmann · Radeberg, DE
• Volker Zipprich-Rasch · Dresden, DE
• Gert Kobernik · Dresden, DE
• Uwe Augustin · Dresden, DE
• Konrad Seidel · Dresden, DE
• Andreas Kux · Haar, DE
• Hans Heitzer · Birkenfeld, DE
• Daniel-André Löhr · Dresden, DE
• Soren Irmer · Radebeul, DE

Key dates

• Filing date: Jan 30, 2007
• Grant date: Feb 10, 2009
• Expiry date: Aug 11, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G11C16/26
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A memory device is provided including memory cells that are capable of switching between at least two states, where the threshold of a sense signal for detecting the current state depends on a data content of the memory cell. Parallel to a user data block, a primary control word including a predetermined number of bits of a first state is stored in a check section of the cell array. The check section is read by applying sense signals of different amplitudes, where in each case a secondary control word is obtained. By checking in each secondary control word the number of bits of the first state, the margins of the current sense signal amplitude towards the sense window limits may be checked and the sense signal amplitude may be adapted permanently to a sense window drift, so as to enhance the reliability of the memory device.