Contextual Info: HN62W454B Series 262144-word x 16-bit CMOS Mask Programmable ROM HITACHI ADE-203-682 Z Preliminary Rev. 0.0 Nov. 18, 1996 Description The HN62W454B is a 262144 words by 16 bits CMOS Mask Programmable ROM. A high speed access of 120/150 ns (max) is the most suitable to the system using a high speed micro-computer by 16 bits.