mt46h32m32lfcm-6 Micron Semiconductor Products, mt46h32m32lfcm-6 Datasheet - Page 34

• Manufacturer Part Number: mt46h32m32lfcm-6
• Description: 1gb X16, X32 Mobile Ddr Sdram
• Manufacturer: Micron Semiconductor Products

AUTO REFRESH
SELF REFRESH
PDF: 09005aef82ce3074/Source: 09005aef82cd0158
ddr_mobile_sdram_cmd_op_timing_dia_fr5.08__3.fm - Rev. G 07/08 EN
AUTO REFRESH is used during normal operation of the Mobile DDR SDRAM and is
analogous to CAS#-BEFORE-RAS# (CBR) REFRESH in FPM/EDO DRAMs. The AUTO
REFRESH command is nonpersistent and must be issued each time a refresh is required.
The addressing is generated by the internal refresh controller. This makes the address
bits a “Don’t Care” during an AUTO REFRESH command.
To provide improved efficiency in scheduling and switching between tasks, some flexi-
bility in the absolute refresh interval is provided. The auto refresh period begins when
the AUTO REFRESH command is registered and ends
The SELF REFRESH command can be used to retain data in the Mobile DDR SDRAM,
even if the rest of the system is powered down. When in the self refresh mode, the Mobile
DDR SDRAM retains data without external clocking. The SELF REFRESH command is
initiated like an AUTO REFRESH command, except that CKE is disabled (LOW). All
command and address input signals except CKE are “Don’t Care” during SELF REFRESH.
See Figure 48 on page 80 for details on entering and exiting self refresh mode.
During SELF REFRESH, the device is refreshed as identified in the extended mode
register (see “Partial-Array Self Refresh (PASR)” on page 47). An internal temperature
sensor will adjust the refresh rate to optimize device power consumption while ensuring
data integrity (see “Temperature-Compensated Self Refresh (TCSR)” on page 47).
The procedure for exiting SELF REFRESH requires a sequence of commands. First, CK
must be stable prior to CKE going back HIGH. When CKE is HIGH, the Mobile DDR
SDRAM must have NOP commands issued for
During SELF REFRESH operation, refresh intervals are scheduled internally and may
vary. These refresh intervals may be different then the specified
reason, the SELF REFRESH command must not be used as a substitute for the AUTO
REFRESH command.
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Micron Technology, Inc., reserves the right to change products or specifications without notice.
1Gb: x16, x32 Mobile DDR SDRAM
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XSR time.
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RFC later.
©2007 Micron Technology, Inc. All rights reserved
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REFI time. For this
Commands