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ADVANCE
4, 8 MEG x 32
DRAM SODIMMs
GENERAL DESCRIPTION
The MT2LDT432H (X)(S) and MT4LDT832H (X)(S)
FAST-PAGE-MODE READ, except data will be held
are randomly accessed 16MB and 32MB memories
valid or become valid after CAS# goes HIGH, as long as
organized in a small-outline x32 configuration. They
RAS# and OE# are held LOW. (Refer to the 4 Meg x 16
are specially processed to operate from 3V to 3.6V for
[MT4LC4M16R6] DRAM data sheet for additional
low-voltage memory systems.
information on EDO functionality.)
During READ or WRITE cycles, each bit is uniquely
addressed through the address bits, which are entered
12 bits (A0-A11) at a time. RAS# is used to latch the first
12 bits and CAS# the latter 10 bits.
READ and WRITE cycles are selected with the WE#
input. A logic HIGH on WE# dictates read mode, while
a logic LOW on WE# dictates write mode. During a
WRITE cycle, data-in (D) is latched by the falling edge
of WE# or CAS#, whichever occurs last. If WE# goes
LOW prior to CAS# going LOW, the output pin(s)
remain open (High-Z) until the next CAS# cycle.
REFRESH
Memory cell data is retained in its correct state by
maintaining power and executing any RAS# cycle
(READ, WRITE) or RAS# refresh cycle (RAS#-ONLY,
CBR or HIDDEN) so that all combinations of RAS#
addresses are executed at least every tREF, regardless of
sequence. The CBR REFRESH cycle will invoke the
internal refresh counter for automatic RAS# address-
ing.
An optional self refresh mode is also available. The
FAST PAGE MODE
“S” option allows the user the choice of a fully static,
low-power data retention mode or a dynamic refresh
FAST-PAGE-MODE operations allow faster data
mode at the extended refresh period of 128ms. The
operations (READ or WRITE) within a row-address-
optional self refresh feature is initiated by performing
defined page boundary. The FAST-PAGE-MODE cycle
a CBR REFRESH cycle and holding RAS# LOW for the
is always initiated with a row address strobed in by
et4U.com RAS#, followed by a column address strobed in by
specified tRASS.
The self refresh mode is terminated by driving RAS# DataShee
CAS#. Additional columns may be accessed by provid-
HIGH for a minimum time of tRPS. This delay allows
ing valid column addresses, strobing CAS# and DhaotladS- heet4Ufo.crotmhe completion of any internal refresh cycles that
ing RAS# LOW, thus executing faster memory cycles.
may be in process at the time of the RAS# LOW-to-
Returning RAS# HIGH terminates the FAST-PAGE-
HIGH transition. If the DRAM controller uses a distrib-
MODE operation.
uted refresh sequence, a burst refresh is not required
upon exiting self refresh. However, if the DRAM con-
EDO PAGE MODE
EDO PAGE MODE, designated by the “X” version,
is an accelerated FAST-PAGE-MODE cycle. The pri-
mary advantage of EDO is the availability of data-out
troller utilizes a RAS#-ONLY or burst refresh sequence,
all rows must be refreshed within the average internal
refresh rate, prior to the resumption of normal opera-
tion.
even after CAS# goes back HIGH. EDO provides for
CAS# precharge time (tCP) to occur without the out-
STANDBY
put data going invalid. This elimination of CAS#
Returning RAS# and CAS# HIGH terminates a
output control provides for pipelined READs.
memory cycle and decreases chip current to a reduced
FAST-PAGE-MODE modules have traditionally
standby level. Also, the chip is preconditioned for the
turned the output buffers off (High-Z) with the rising
next cycle during the RAS# HIGH time.
edge of CAS#. EDO operates as any DRAM READ or
DataSheet4U.com
4, 8 Meg x 32 DRAM SODIMMs
DM89.p65 – Rev. 12/98
DataSheet4 U .com
2 Micron Technology, Inc., reserves the right to change products or specifications without notice.
©1998, Micron Technology, Inc.
