Patents Represented by Attorney, Agent or Law Firm Tho
  • Patent number: 6185143
    Abstract: Resistance of a selected memory cell in a Magnetic Random Access Memory (“MRAM”) device is sensed by a read circuit including a differential amplifier, a first current mode preamplifier coupled to a sense node of the differential amplifier, and a second current mode preamplifier coupled to a reference node of the differential amplifier. During a read operation, the first preamplifier applies a regulated voltage to the selected memory cell, and the second preamplifier applies a regulated voltage to a reference cell. A sense current flows through the selected memory cell and to the sense node of the differential amplifier, while a reference current flows through the reference cell and to the reference node of the differential amplifier. Resulting is a differential voltage across sense and reference nodes. The differential voltage indicates whether a logic value of ‘0’ or ‘1’ is stored in the selected memory cell.
    Type: Grant
    Filed: February 4, 2000
    Date of Patent: February 6, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Frederick A Perner, Kenneth I Eldredge, Lung T Tran