DESCRIPTION
The MSM518122 is an 1-Mbit CMOS multiport DRAM composed of a 131,072-word by 8-bit dynamic RAM and a 256-word by 8-bit SAM. Its RAM and SAM operate independently and asynchronously.
The MSM518122 supports three types of operation : random access to RAM port, high speed serial access to SAM port and bidirectional transfer of data between any selected row in the RAM port and the SAM port. In addition to the conventional multiport DRAM operating modes, the MSM518122 features the block write and flash write functions on the RAM port and a split data transfer capability on the SAM port. The SAM port requires no refresh operation because it uses static CMOS flip-flops.

FEATURES
• Single power supply: 5 V ±10%
• Full TTL compatibility
• Multiport organization
    RAM: 128K word x 8 bits
    SAM: 256 word x 8 bits
• Fast page mode
• Write per bit
• Masked flash write
• Masked block write
• RAS only refresh
• CAS before RAS refresh
• Hidden refresh
• Serial read/write
• 256 tap location
• Bidirectional data transfer
• Split transfer
• Masked write transfer
• Refresh: 512 cycles/8 ms
• Package options:
    40-pin 475 mil plastic ZIP (ZIP40-P-475-1.27) (Product : MSM518122-xxZS)
    40-pin 400 mil plastic SOJ (SOJ40-P-400-1.27) (Product : MSM518122-xxJS)
                                                                           xx indicates speed rank.