Abstract: To ensure that a memory device operates in self-refresh mode, the memory controller includes (1) a normal-mode output buffer for driving a clock enable signal CKE onto the memory device's CKE input and (2) a power island for driving a clock enable signal CKE_prime onto that same input. To power down the memory controller, the normal-mode output buffer drives signal CKE low, then the power island drives signal CKE_prime low, then the memory controller (except for the power island) is powered down. The power island continues to drive the memory device's CKE input low to ensure that the memory device stays in self-refresh mode while the memory controller is powered substantially off. To resume normal operations, the power module powers up the memory controller, then the normal-mode output buffer drives signal CKE low, then the power island is disabled, then the memory controller resumes normal operations of the memory device.

Abstract: To ensure that a memory device operates in self-refresh mode, the memory controller includes (1) a normal-mode output buffer for driving a clock enable signal CKE onto the memory device's CKE input and (2) a power island for driving a clock enable signal CKE_prime onto that same input. To power down the memory controller, the normal-mode output buffer drives signal CKE low, then the power island drives signal CKE_prime low, then the memory controller (except for the power island) is powered down. The power island continues to drive the memory device's CKE input low to ensure that the memory device stays in self-refresh mode while the memory controller is powered substantially off. To resume normal operations, the power module powers up the memory controller, then the normal-mode output buffer drives signal CKE low, then the power island is disabled, then the memory controller resumes normal operations of the memory device.

Abstract: A margin violation detector for detecting margin violations of critical paths, a method of monitoring data paths and an IC. In one embodiment, the margin violation detector includes: (1) a monitor flip-flop having a monitor input couplable to a critical path input of a capture flip-flop of a critical path, (2) an exclusive OR gate having a first input couplable to an output of the capture flip-flop and a second input couplable to an output of the monitor flip-flop and (3) a violation detect flip-flop having a detection input couplable to an output of the exclusive OR gate.