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These two integrated circuits were made by National Semiconductor long time ago.
MM5402= 4-digit 12/24-Hours Alarm Clock, 60Hz
MM5456= Alarm Clock Radio
That is all data available from me from a Digital Data Digest 1990. It is sure these ICs have become obsolote.
I suggest you turning to customer support for the National Semiconductor's site at h**p://www.national.com where they may still have data sheets for these old ICs.