Wafer-level package having asynchronous fifo buffer used to deal with data transfer between different dies and associated method

A method for managing data transfer between a first die and a second die in a wafer-level package, comprising:

• generating a first clock from a first clock source;
• generating transmit data from a first sub-system in the first die;
• outputting the transmit data via an output circuit of the first die according to the first clock;
• generating a second clock from a second clock source;
• buffering the transmit data transferred from the output circuit in an asynchronous first-in first-out (FIFO) buffer in an input circuit of the second die;
• and
• outputting the buffered transmit data in the asynchronous FIFO buffer to a second sub-system in the second die according to the second clock.

A wafer-level package comprising:

• a first die, comprising:
• a first clock source;
• and
• a second die, comprising:
• a second clock source;
• wherein the first die is identical to the second die, the first clock source is used to generate a clock shared by the first die and the second die, and the second clock source is not used to generate a clock used by any of the first die and the second die.