M391B5273CH0 SAMSUNG [Samsung semiconductor], M391B5273CH0 Datasheet - Page 16

• Manufacturer Part Number: M391B5273CH0
• Description: 240pin Unbuffered DIMM based on 2Gb C-die
• Manufacturer: SAMSUNG [Samsung semiconductor]

Unbuffered DIMM
12.2 V
The dc-tolerance limits and ac-noise limits for the reference voltages V
V
V
thermore V
which setup and hold is measured. System timing and voltage budgets need to account for V
data-eye of the input signals.
Timing and voltage effects due to ac-noise on V
The voltage levels for setup and hold time measurements V
"V
This clarifies, that dc-variations of V
This also clarifies that the DRAM setup/hold specification and derating values need to include time and voltage associated with V
REF
REF
REF
(t) as a function of time. (V
(DC) is the linear average of V
" shall be understood as V
REF
REF
Tolerances.
(t) may temporarily deviate from V
voltage
REF
REF
REF
stands for V
(DC), as defined in Figure 2.
REF
(t) over a very long period of time (e.g. 1 sec). This average has to meet the min/max requirements of V
affect the absolute voltage a signal has to reach to achieve a valid high or low level and therefore the time to
Figure 2. Illustration of VREF(DC) tolerance and VREF ac-noise limits
REF
REFCA
REF
up to the specified limit (+/-1% of V
(DC) by no more than ± 1% V
and V
datasheet
IH
REFDQ
(AC), V
likewise).
IH
(DC), V
REFCA
- 16 -
IL
and V
(AC) and V
DD
.
REFDQ
DD
) are included in DRAM timings and their associated deratings.
IL
are illustrate in Figure 2. It shows a valid reference voltage
(DC) are dependent on V
REF
(DC) deviations from the optimum position within the
V
V
SS
DD
REF
time
.
DDR3 SDRAM
REF
ac-noise.
Rev. 1.21
REF
. Fur-