MSM5412222A Datasheet, PDF (1/13 Pages) OKI electronic componets – 262,214-Word x 12-Bit Field Memory

OKI ^{Semiconductor}
MSM5412222A
262,214-Word x 12-Bit Field Memory
REVISION-3 1999.6.10
DESCRIPTION
The OKI MSM5412222A is a high performance 3-Mbit, 256K X 12-bit, Field Memory. It is
especially designed for high-speed serial access applications such as HDTVs, conventional
NTSC TVs, VTRs, digital movies and Multi-media systems. MSM5412222A is a FRAM for wide
or low end use in general commodity TVs and VTRs exclusively. MSM5412222A is not
designed for high end use in medical systems, professional graphics systems which require
long term picture storage, data storage systems and others. Two or more MSM5412222As can
be cascaded directly without any delay devices between them. (Cascading provides larger
storage depth or a longer delay).
Each of the 12-bit planes has separate serial write and read ports. These employ independent
control clocks to support asynchronous read and write operations. Different clock rates are also
supported, which allow alternate data rates between write and read data streams.
The MSM5412222A provides high speed FIFO, First-In First-Out, operation without external
refreshing: MSM5412222A refreshes its DRAM storage cells automatically, so that it appears
fully static to the users.
Moreover, fully static type memory cells and decoders for serial access enable the refresh free
serial access operation, so that serial read and/or write control clock can be halted high or low
for any duration as long as the power is on. Internal conflicts of memory access and refreshing
operations are prevented by special arbitration logic.
The MSM5412222A’s function is simple, and similar to a digital delay device whose delay-bit-
length is easily set by reset timing. The delay length, and the number of read delay clocks
between write and read, is determined by externally controlled write and read reset timings.
Additional SRAM serial registers, or line buffers for the initial access of 256 X 12-bit enable high
speed first-bit-access with no clock delay just after the write or read reset timings.
Additionally, the MSM5412222A has a write mask function or input enable function (IE), and
read-data skipping function or output enable function (OE). The differences between write
enable (WE) and input enable (IE), and between read enable (RE) and output enable (OE) are
that WE and RE can stop serial write/read address increments, but IE and OE cannot stop the
increment, when write/read clocking is continuously applied to MSM5412222A. The input
enable (IE) function allows the user to write into selected locations of the memory only, leaving
the rest of the memory contents unchanged. This facilitates data processing to display a
“picture in picture” on a TV screen.
The MSM5412222A is similar in operation and functionality to OKI 1-Mbit Field Memory
MSM514222C and 2-Mbit Field Memory MSM518222A. Three MSM514222Cs or one
MSM514222C plus one MSM518222A can be replaced simply by one MSM5412222A.