MT46V256M4TG-75:A Micron Technology Inc, MT46V256M4TG-75:A Datasheet - Page 79

• Manufacturer Part Number: MT46V256M4TG-75:A
• Description: IC DDR SDRAM 1GBIT 7.5NS 66TSOP
• Manufacturer: Micron Technology Inc

Specifications of MT46V256M4TG-75:A

• Format - Memory: RAM
• Memory Type: DDR SDRAM
• Memory Size: 1G (256M x 4)
• Speed: 7.5ns
• Interface: Parallel
• Voltage - Supply: 2.3 V ~ 2.7 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 66-TSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Figure 51:
SELF REFRESH
PDF: 09005aef80a2f898/Source: 09005aef82a95a3a
DDR_x4x8x16_Core2.fm - 1Gb DDR: Rev. I, Core DDR: Rev. B 12/07 EN
Command
BA0, BA1
Address
DQS
DM
DQ
CK#
CKE
A10
CK
5
5
5
Auto Refresh Mode
NOP 1
t IS
t IS
T0
Notes:
t IH
t IH
One bank
All banks
Bank(s) 4
t IS t IH
PRE
Although not a JEDEC requirement, to provide for future functionality features, CKE
must be active (HIGH) during the AUTO REFRESH period. The AUTO REFRESH period
begins when the AUTO REFRESH command is registered and ends
1. NOP commands are shown for ease of illustration; other valid commands may be possible at
2. NOP or COMMAND INHIBIT are the only commands allowed until after
3. The second AUTO REFRESH is not required and is only shown as an example of two back-to-
4. “Don’t Care” if A10 is HIGH at this point; A10 must be HIGH if more than one bank is active
5. DM, DQ, and DQS signals are all “Don’t Care”/High-Z for the operations shown.
When in the self refresh mode, the DDR SDRAM retains data without external clocking.
The DLL is automatically disabled upon entering SELF REFRESH and is automatically
enabled upon exiting SELF REFRESH (a DLL reset and 200 clock cycles must then occur
before a READ command can be issued). Input signals except CKE are “Don’t Care”
during SELF REFRESH. V
REFRESH.
The procedure for exiting SELF REFRESH requires a sequence of commands. First, CK
and CK# must be stable prior to CKE going back HIGH. Once CKE is HIGH, the DDR
SDRAM must have NOP commands issued for
completion of any internal refresh in progress. A simple algorithm for meeting both
refresh and DLL requirements is to apply NOPs for
T1
these times. CKE must be active during clock-positive transitions.
be active during clock-positive transitions.
back AUTO REFRESH commands.
(that is, must precharge all active banks).
CK
NOP 1
Valid
T2
t CH
t RP
t CL
NOP 1
T3
REF
voltage is also required for the full duration of SELF
AR
T4
79
(
(
(
(
(
(
(
(
(
)
)
)
)
)
)
)
)
)
(
(
(
(
(
(
(
(
(
)
)
)
)
)
)
)
)
)
(
(
(
(
(
(
(
(
(
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
)
)
)
)
)
)
)
)
)
t RFC
NOP 1,2
Ta0
Micron Technology, Inc., reserves the right to change products or specifications without notice.
t
XSNR because time is required for the
AR 3
Ta1
1Gb: x4, x8, x16 DDR SDRAM
t
XSRD time, then a DLL RESET (via
(
(
(
(
(
(
(
(
(
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
)
)
)
)
)
)
)
)
)
(
(
(
(
(
(
(
(
(
)
)
)
)
)
)
)
)
)
(
(
(
(
(
(
(
(
(
)
)
)
)
)
)
)
)
)
NOP 1,2
Valid
Tb0
©2003 Micron Technology, Inc. All rights reserved.
t RFC
t
RFC later.
NOP 1
Tb1
t
RFC time; CKE must
Operations
Don’t Care
ACT
Tb2
RA
RA
BA