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    參數(shù)資料
    型號: MT46V4M32
    廠商: Micron Technology, Inc.
    英文描述: DOUBLE DATA RATE DDR SDRAM
    中文描述: 雙倍數(shù)據(jù)速率的DDR SDRAM內(nèi)存
    文件頁數(shù): 13/66頁
    文件大?。?/td> 1921K
    代理商: MT46V4M32
    13
    128Mb: x32 DDR SDRAM
    4M32DDR_B.p65 – Rev. B, Pub. 7/02
    Micron Technology, Inc., reserves the right to change products or specifications without notice.
    2002, Micron Technology, Inc.
    128Mb: x32
    DDR SDRAM
    ADVANCE
    AUTO REFRESH
    AUTO REFRESH is used during normal operation of
    the DDR SDRAM and is analogous to CAS#-BEFORE-
    RAS# (CBR) REFRESH in FPM/EDO DRAMs. This com-
    mand is nonpersistent, so it 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. The 128 Mb x32
    DDR SDRAM requires AUTO REFRESH cycles at an
    average interval of 7.8μs (maximum).
    To allow for improved efficiency in scheduling and
    switching between tasks, some flexibility in the abso-
    lute refresh interval is provided. A maximum of eight
    AUTO REFRESH commands can be posted to any given
    DDR SDRAM, meaning that the maximum absolute
    interval between any AUTO REFRESH command and
    the next AUTO REFRESH command is 18 × 7.8μs
    (140.4μs). This maximum absolute interval is to allow
    future support for DLL updates internal to the DDR
    SDRAM to be restricted to AUTO REFRESH cycles,
    without allowing excessive drift in
    t
    AC between updates.
    This is a JEDEC requirement that is
    NOT
    required for
    Micron’s 128Mb x32 DDR device.
    SELF REFRESH
    The SELF REFRESH command can be used to retain
    data in the DDR SDRAM, even if the rest of the system
    is powered down. When in the self refresh mode, the
    DDR SDRAM retains data without external clocking.
    The SELF REFRESH command is initiated like an AUTO
    REFRESH command except CKE is disabled (LOW). The
    DLL is automatically disabled upon entering SELF RE-
    FRESH and is automatically enabled upon exiting SELF
    REFRESH (200 clock cycles must then occur before a
    READ command can be issued). Input signals except
    CKE are “Don’t Care” during SELF REFRESH.
    The procedure for exiting self refresh requires a se-
    quence of commands. First, CK must be stable prior to
    CKE going back HIGH. Once CKE is HIGH, the DDR
    SDRAM must have NOP commands issued for
    t
    XSNR
    because time is required for the completion of any in-
    ternal refresh in progress. A simple algorithm for meet-
    ing both refresh and DLL requirements is to apply
    NOPs for 200 clock cycles before applying any other
    command.
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    MT46V4M32LG 制造商:MICRON 制造商全稱:Micron Technology 功能描述:DOUBLE DATA RATE DDR SDRAM
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