An integrated circuit (IC) package includes an interface die and a separate storage die. The interface die has a synchronous interface to receive memory access commands from an external memory controller, and has a plurality of clockless memory control interfaces to output row and column control signals that correspond to the memory access commands. The storage die has a plurality of independently accessible storage arrays and corresponding access-control interfaces to receive the row and column control signals from the clockless memory control interfaces, each of the access-control interfaces including data output circuitry to output read data corresponding to a given one of the memory access commands in a time-multiplexed transmission.