h5ps1g43efr Hynix Semiconductor, h5ps1g43efr Datasheet - Page 27

• Manufacturer Part Number: h5ps1g43efr
• Description: 1gb Ddr2 Sdram
• Manufacturer: Hynix Semiconductor

Rev. 0.1 / May 2008
4. Differential data strobe
DDR2 SDRAM pin timings are specified for either single ended mode or differential mode depending on the
setting of the EMR “Enable DQS” mode bit; timing advantages of differential mode are realized in system
design. The method by which the DDR2 SDRAM pin timings are measured is mode dependent. In single
ended mode, timing relationships are measured relative to the rising or falling edges of DQS crossing at VREF.
In differential mode, these timing relationships are measured relative to the crosspoint of DQS and its com-
plement, DQS. This distinction in timing methods is guaranteed by design and characterization. Note that
when differential data strobe mode is disabled via the EMR, the complementary pin, DQS, must be tied exter-
nally to VSS through a 20 Ω to 10 KΩ resistor to insure proper operation.
5. AC timings are for linear signal transitions. See System Derating for other signal transitions.
6. All voltages referenced to VSS.
7. These parameters guarantee device behavior, but they are not necessarily tested on each device. They
may be guaranteed by device design or tester correlation.
8. Tests for AC timing, IDD, and electrical (AC and DC) characteristics, may be conducted at nominal refer-
ence/supply voltage levels, but the related specifications and device operation are guaranteed for the full
voltage range specified.
CK/CK
DQS/DQS
DQ
DQS/
DQS
DQ
DM
CK
CK
DQS
DQS
t
CH
t
t
RPRE
DQS
DQS
WPRE
Figure -- Data output (read) timing
V
V
IL
IH
(ac)
(ac)
t
DMin
DS
t
t
CL
DQSQmax
D
Figure -- Data input (write) timing
t
DQSH
V
V
IH
IL
(ac)
(ac)
t
DMin
t
DS
QH
D
Q
t
DQSL
DMin
Q
D
t
DH
V
IH
V
(dc)
IL
(dc)
t
DQSQmax
DMin
Q
V
D
t
IL
DH
(dc)
V
IH
t
WPST
(dc)
t
t
RPST
QH
Q
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