
- 16 -
Rev 1.6 (Apr. 2005)
256M gDDR2 SDRAM
K4N56163QF-GC
3. gDDR2 SDRAM output slew rate test load
Output slew rate is characterized under the test conditions as shown in the following figure.
4. Differential data strobe
gDDR2 SDRAM pin timings are specified for either single ended mode or differential mode depending on the setting of the EMRS
“Enable DQS” mode bit; timing advantages of differential mode are realized in system design. The method by which the gDDR2 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
complement, DQS. This distinction in timing methods is guaranteed by design and characterization. Note that when differential data
strobe mode is disabled via the EMRS, the complementary pin, DQS, must be tied externally to VSS through a 20 ohm
to 10 K ohm
resisor to insure proper operation.
5. AC timings are for linear signal transitions.
6. These parameters guarantee device behavior, but they are not necessarily tested on each device.
They may be guaranteed by device design or tester correlation.
VDDQ
DUT
DQ
DQS, DQS
Output
V
TT
= V
DDQ
/2
25
Test point
<Slew Rate Test Load>
t
DS
t
DS
t
DH
t
WPRE
t
WPST
t
DQSH
t
DQSL
DQS
DQS
D
DMin
DQS/
DQS
DQ
DM
t
DH
<Data input (write) timing>
DMin
DMin
DMin
D
D
D
V
IL
(ac)
V
IH
(ac)
V
IL
(ac)
V
IH
(ac)
V
IL
(dc)
V
IH
(dc)
V
IL
(dc)
V
IH
(dc)
t
CH
t
CL
CK
CK
CK/CK
DQS/DQS
DQ
DQS
DQS
t
RPST
Q
t
RPRE
t
DQSQmax
t
QH
t
QH
t
DQSQmax
<Data output (read) timing>
Q
Q
Q