International Business Machines Corporation

Infineon Technologies Ag

Samuel K Weinstein

Alan D Norris

Mark David Jacunski

Stephan Wuensche

Frank David Ferraiolo

Albert Manhee Chu

Allan Robert Bertolet

A DDR DRAM having a test mode and an operational mode and a method for testing the DDR DRAM. The method includes in the order recited: (a) placing the DDR DRAM in test mode; (b) issuing a bank activate command to select and bring up a wordline selected for write of the DDR DRAM; (c) writing with auto-precharge, a test pattern to cells of the DDR DRAM; (d) repeating steps (b) and (c) until all wordlines for write have been selected; (e) issuing a bank activate command to select and bring up a wordline selected for read of the DDR DRAM; (f) reading with auto-precharge, the stored test pattern from cells of the DDR DRAM; and (g) repeating steps (e) and (f) until all wordlines for read have been selected.

Method for performing a burn-in test

A DDR DRAM having a test mode and an operational mode and a method for testing the DDR DRAM. The method includes in the order recited: (a) placing the DDR DRAM in test mode; (b) issuing a band activate command to select and bring up a wordline selected for write of the DDR DRAM; (c) writing with auto-precharge, a test pattern to cells of the DDR DRAM; (d) repeating steps (b) and (c) until all wordlines for write have been selected; (e) issuing a bank activate command to select and bring up a wordline selected for read of the DDR DRAM; (f) reading with auto-precharge, the stored test pattern from cells of the DDR DRAM; and (g) repeating steps (c) and (f) until all wordlines for read have been selected.

A SDRAM. The SDRAM including: at least one bank of DRAM cells; the SDRAM operable to a first specification defined by a first clock frequency, a first write recovery time and a first time interval for precharge to row address strobe; and means for programming the SDRAM operable to a second specification defined by a second clock frequency, a second write recovery time and a second time interval for precharge to row address strobe.

Timer lockout circuit for synchronous applications

A SDRAM mid a tinier lockout circuit. The SDRAM including: at least one bank of DRAM cells; the SDRAM operable to a first specification defined by a first clock frequency, a first write recovery time and a first time interval for precharge to row address strobe; and a circuit for programming the SDRAM operable to a second specification defined by a second clock frequency, a second write recovery time and a second time interval for precharge to row address strobe.

A glitch free delay line multiplexing technique is described that includes an intermediate multiplexing system and an output multiplexer. The intermediate multiplexing system receives signals from a plurality of delay units and outputs a subset of delay signals that includes the signal presently selected, the signal presently selected with an additional delay, and the signal presently selected with one less delay. The intermediate multiplexing system receives a control word from a select mechanism in a non-time critical manner. The output multiplexer receives the least significant bits of the control word and outputs the selected signal.

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Burlington, VT, United States of America

Samuel K Weinstein