Patent ID: 6608507
Filing Date: 2003-08-19
Classification: G06F,G11C,H03K,H04L

Abstract:
A method of adjusting an output driver characteristic of an integrated circuit memory device that is included in a memory system, wherein the memory system includes an integrated circuit controller device coupled to the memory device via at least a first signal line, the method comprising:providing a command to the memory device that specifies a calibration mode, wherein the command is provided by the controller device; during the calibration mode: driving a voltage level onto the first signal line using a first output driver, wherein a first voltage level is derived from an amount of voltage swing generated by the first output driver driving the voltage level onto the first signal line; actively coupling a first comparator to the first signal line; when the first comparator is coupled to the first signal line, comparing the first voltage level with a reference voltage using the first comparator; adjusting the amount of voltage swing to arrive at a calibrated voltage swing level, wherein: the amount of voltage swing is decreased when the first voltage level exceeds the reference voltage level; and the amount of voltage swing is increased when the reference voltage level exceeds the first voltage level; and actively isolating the first comparator from the first signal line upon exiting the calibration mode, wherein the memory device is operable in a normal read operation upon exiting the calibration mode, wherein, during the normal read operation, the first output driver is operable to output data onto the first signal line in accordance with the calibrated voltage swing level.