MT48H4M16LFB4-75 IT:H Micron Technology Inc, MT48H4M16LFB4-75 IT:H Datasheet - Page 16

• Manufacturer Part Number: MT48H4M16LFB4-75 IT:H
• Manufacturer: Micron Technology Inc
• Type: SDRAMr

Specifications of MT48H4M16LFB4-75 IT:H

• Organization: 4Mx16
• Density: 64Mb
• Address Bus: 14b
• Maximum Clock Rate: 133MHz
• Operating Supply Voltage (typ): 1.8V
• Package Type: VFBGA
• Operating Temp Range: -40C to 85C
• Operating Supply Voltage (max): 1.9V
• Operating Supply Voltage (min): 1.7V
• Supply Current: 50mA
• Pin Count: 54
• Mounting: Surface Mount
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Compliant

PRECHARGE
BURST TERMINATE
Auto Precharge
AUTO REFRESH
SELF REFRESH
PDF: 09005aef8237ed98/Source: 09005aef8237ed68
64mb_x16_Mobile SDRAM_Y24L_2.fm - Rev. C 10/07 EN
The PRECHARGE command is used to deactivate the open row in a particular bank or
the open row in all banks. The bank(s) will be available for a subsequent row access a
specified time (
whether one or all banks are to be precharged, and in the case where only one bank is to
be precharged, inputs BA0, BA1 select the bank. Otherwise BA0, BA1 are treated as
“Don’t Care.” After a bank has been precharged, it is in the idle state and must be acti-
vated prior to any READ or WRITE commands being issued to that bank.
The BURST TERMINATE command is used to truncate fixed-length bursts. The most
recently registered READ or WRITE command prior to the BURST TERMINATE
command will be truncated, as shown in “Operations” on page 18.
Auto precharge is a feature that performs the same individual-bank PRECHARGE func-
tion described above, without requiring an explicit command. This is accomplished by
using A10 to enable auto precharge in conjunction with a specific READ or WRITE
command. A precharge of the bank/row that is addressed with the READ or WRITE
command is automatically performed upon completion of the READ or WRITE burst.
Auto precharge is nonpersistent in that it is either enabled or disabled for each indi-
vidual READ or WRITE command.
Auto precharge ensures that the precharge is initiated at the earliest valid stage within a
burst. The user must not issue another command to the same bank until the precharge
time (
issued at the earliest possible time, as described for each burst type in “Operations” on
page 18.
AUTO REFRESH is used during normal operation of the SDRAM and is analogous to
CAS#-BEFORE-RAS# (CBR) refresh in conventional DRAM. This command is nonpersis-
tent, so it must be issued each time a refresh is required. All active banks must be
PRECHARGED prior to issuing an AUTO REFRESH command. The AUTO REFRESH
command should not be issued until the minimum
PRECHARGE command, as shown in “Operations” on page 18.
The addressing is generated by the internal refresh controller. This makes the address
bits “Don’t Care” during an AUTO REFRESH command. The 64Mb SDRAM requires
4,096 AUTO REFRESH cycles every 64ms (
command every 15.625µs will meet the refresh requirement and ensure that each row is
refreshed. Alternatively, 4,096 AUTO REFRESH commands can be issued in a burst at the
minimum cycle rate (
The SELF REFRESH command can be used to retain data in the SDRAM, even if the rest
of the system is powered down, as long as power is not completely removed from the
SDRAM. When in the self refresh mode, the SDRAM retains data without external
clocking. The SELF REFRESH command is initiated like an AUTO REFRESH command
t
RP) is completed. This is determined as if an explicit PRECHARGE command was
t
RP) after the PRECHARGE command is issued. Input A10 determines
t
RFC), once every 64ms.
16
Micron Technology, Inc., reserves the right to change products or specifications without notice.
t
REF). Providing a distributed AUTO REFRESH
64Mb: 4 Meg x 16 Mobile SDRAM
t
RP has been met after the
©2006 Micron Technology, Inc. All rights reserved.
Commands