MT47H64M16HR-3 Micron Technology Inc, MT47H64M16HR-3 Datasheet - Page 83

• Manufacturer Part Number: MT47H64M16HR-3
• Manufacturer: Micron Technology Inc

Specifications of MT47H64M16HR-3

• Lead Free Status / RoHS Status: Compliant

DLL Enable/Disable
Output Drive Strength
DQS# Enable/Disable
RDQS Enable/Disable
Output Enable/Disable
PDF: 09005aef821ae8bf
Rev. O 9/08 EN
The DLL may be enabled or disabled by programming bit E0 during the LM command,
as shown in Figure 36 (page 82). These specifications are applicable when the DLL is
enabled for normal operation. DLL enable is required during power-up initialization
and upon returning to normal operation after having disabled the DLL for the purpose
of debugging or evaluation. Enabling the DLL should always be followed by resetting
the DLL using the LM command.
The DLL is automatically disabled when entering SELF REFRESH operation and is auto-
matically re-enabled and reset upon exit of SELF REFRESH operation.
Anytime the DLL is enabled (and subsequently reset), 200 clock cycles must occur be-
fore a READ command can be issued to allow time for the internal clock to synchronize
with the external clock. Failing to wait for synchronization to occur may result in a viola-
tion of the
Anytime the DLL is disabled and the device is operated below 25 MHz, any AUTO RE-
FRESH command should be followed by a PRECHARGE ALL command.
The output drive strength is defined by bit E1, as shown in Figure 36 (page 82). The nor-
mal drive strength for all outputs is specified to be SSTL_18. Programming bit E1 = 0
selects normal (full strength) drive strength for all outputs. Selecting a reduced drive
strength option (E1 = 1) will reduce all outputs to approximately 45 to 60 percent of the
SSTL_18 drive strength. This option is intended for the support of lighter load and/or
point-to-point environments.
The DQS# ball is enabled by bit E10. When E10 = 0, DQS# is the complement of the
differential data strobe pair DQS/DQS#. When disabled (E10 = 1), DQS is used in a single-
ended mode and the DQS# ball is disabled. When disabled, DQS# should be left float-
ing; however, it may be tied to ground via a 20Ω to 10kΩ resistor. This function is also
used to enable/disable RDQS#. If RDQS is enabled (E11 = 1) and DQS# is enabled (E10 =
0), then both DQS# and RDQS# will be enabled.
The RDQS ball is enabled by bit E11, as shown in Figure 36 (page 82). This feature is
only applicable to the x8 configuration. When enabled (E11 = 1), RDQS is identical in
function and timing to data strobe DQS during a READ. During a WRITE operation,
RDQS is ignored by the DDR2 SDRAM.
The OUTPUT ENABLE function is defined by bit E12, as shown in Figure 36 (page 82).
When enabled (E12 = 0), all outputs (DQ, DQS, DQS#, RDQS, RDQS#) function normal-
ly. When disabled (E12 = 1), all outputs (DQ, DQS, DQS#, RDQS, RDQS#) are disabled,
thus removing output buffer current. The output disable feature is intended to be used
during Idd characterization of read current.
t
AC or
t
DQSCK parameters.
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Micron Technology, Inc. reserves the right to change products or specifications without notice.
Extended Mode Register (EMR)
1Gb: x4, x8, x16 DDR2 SDRAM
© 2004 Micron Technology, Inc. All rights reserved.