K4T51043QE Datasheet, PDF (22/45 Pages) Samsung semiconductor – 512Mb E-die DDR2 SDRAM Specification

K4T51043QE
K4T51083QE
K4T51163QE
DDR2 SDRAM
14.0 General notes, which may apply for all AC parameters
1. DDR2 SDRAM AC timing reference load
Figure 1 represents the timing reference load used in defining the relevant timing parameters of the part. It is not intended to be either a precise repre
sentation of the typical system environment or a depiction of the actual load presented by a production tester. System designers will use IBIS or other
simulation tools to correlate the timing reference load to a system environment. Manufacturers will correlate to their production test conditions (generally
a coaxial transmission line terminated at the tester electronics).
VDDQ
DUT
DQ
DQS
DQS
RDQS
RDQS
Output
Timing
reference
point
25Ω
V_TT = V_DDQ/2
Figure 1 - AC Timing Reference Load
The output timing reference voltage level for single ended signals is the crosspoint with VTT. The output timing reference voltage level for differential
signals is the crosspoint of the true (e.g. DQS) and the complement (e.g. DQS) signal.
2. Slew Rate Measurement Levels
a) Output slew rate for falling and rising edges is measured between VTT - 250 mV and VTT + 250 mV for single ended signals. For differential signals
(e.g. DQS - DQS) output slew rate is measured between DQS - DQS = - 500 mV and DQS - DQS = + 500 mV. Output slew rate is guaranteed by
design, but is not necessarily tested on each device.
b) Input slew rate for single ended signals is measured from Vref(dc) to VIH(ac),min for rising edges and from Vref(dc) to VIL(ac),max for falling edges.
For differential signals (e.g. CK - CK) slew rate for rising edges is measured from CK - CK = - 250 mV to CK - CK = + 500 mV (+ 250 mV to - 500 mV
for falling edges).
c) VID is the magnitude of the difference between the input voltage on CK and the input voltage on CK, or between DQS and DQS for differential strobe.
3. DDR2 SDRAM output slew rate test load
Output slew rate is characterized under the test conditions as shown in Figure 2.
VDDQ
DUT
DQ
DQS, DQS
RDQS, RDQS
Output
Test point
25Ω
V_TT = V_DDQ/2
Figure 2 - Slew Rate Test Load
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Rev. 1.8 July 2007