1. A method of initializing a sleep mode for an integrated circuit chip comprising external interface circuits and primary components, the method comprising: receiving, via one or more receivers of the external interface circuits, data supplied with a clock signal; sensing an indicator to enter sleep mode, wherein the indicator comprises a loss of the clock signal or receiving a command to enter sleep mode; evaluating the indicator to determine how many components within the integrated circuit chip to deactivate; selectively deactivating one or more primary components in response to the results of the evaluation of the indicator; and maintaining operation of the one or more receivers while the one or more primary components are deactivated; wherein receiving, sensing, evaluating, selectively deactivating, and maintaining operation are performed by the integrated circuit chip; and wherein evaluating the indicator comprises: determining which of the components the indicator indicates should enter sleep mode; and selectively placing at least some of the components into sleep mode in response to determining which components the indicator indicates should enter sleep mode.