HYB18M512160BFX Datasheet, PDF (48/52 Pages) Qimonda AG – DRAMs for Mobile Applications 512-Mbit DDR Mobile-RAM

HYB18M512160BFX
512-Mbit DDR Mobile-RAM
Electrical Characteristics
21) A low level on DQS may be maintained during High-Z states (DQS drivers disabled) by adding a weak pull-down element
in the system. It is recommended to turn off the weak pull-down element during read and write bursts (DQS drivers
enabled).
22) These parameters account for the number of clock cycles and depend on the operating frequency, as follows:
no. of clock cycles = specified delay / clock period ; round to the next higher integer.
23) t_DAL = (t_WR / t_CK) + (t_RP / t_CK): for each of the terms above, if not already an integer, round to the next higher integer.
24) A maximum of eight AUTOREFRESH commands can be posted to the DDR Mobile-RAM device, meaning that the
maximum absolute interval between any Refresh command and the next Refresh command is 8 * tREFI.
Table 24 Output Slew Rate Characteristics ¹⁾
Parameter
Typical Range Minimum
Maximum Unit Notes
Pullup and Pulldown Slew Rate
(Full Drive Buffer)
TBD
0.7
2.5
V/ns ²⁾
Pullup and Pulldown Slew Rate
(Half Drive Buffer)
TBD
0.3
1.0
V/ns ²⁾
Output Slew Rate Matching Ratio
(Pullup to Pulldown)
-
0.7
1.4
-
3)
1) Output slew rate is measured between V_ILD(DC) and V_IHD(AC) (rising) or V_IHD(DC) and V_ILD(AC) (falling).
2) The parameter is measured using a 20pF capacitive load connected to VSSQ.
3) The ratio of the pullup slew rate to the pulldown slew rate is specified for the same temperature and voltage, over the entire
temperature and voltage range. For a given output, it represents the maximum difference between pullup and pulldown
drivers due to process variation.
Table 25 AC Overshoot / Undershoot Specification
Parameter
Maximum peak amplitude allowed for overshoot
Maximum peak amplitude allowed for undershoot
Maximum overshoot area above VDD
Maximum undershoot area below VSS
Maximum
0.9
0.9
3.0
3.0
Unit
V
V
V-ns
V-ns
Notes
–
–
–
–
3.0
2.5
2.0
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
Overshoot
Max. Amplitude = 0.9V
Max. Area = 3V-ns
Undershoot
1
2
3
4
5
6
time (ns)
Figure 39 AC Overshoot and Undershoot Definition
VDD
VSS
7
Data Sheet
48
Rev. 1.10, 2006-11
04052006-4SYQ-ZRN3