W199 Datasheet, PDF (12/14 Pages) Cypress Semiconductor – Spread Spectrum FTG for VIA Apollo Pro-133

PRELIMINARY
W199
SDRAM 0:11,_F Clock Outputs (Lump Capacitance Test Load = 22 pF)
SDRAMIN =
66.8 MHz
SDRAMIN =
100 MHz
SDRAMIN =
133 MHz
Parameter Description Test Condition/Comments Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit
t_P
Period
Measured on rising edge at 15
1.5V
15.5 10
10.5 7.5
8.0 ns
t_H
High Time
Duration of clock cycle above 5.2
3.0
1.87
ns
2.4V
t_L
Low Time
Duration of clock cycle below 5.0
2.0
1.67
ns
0.4V
t_R
Output Rise Edge Measured from 0.4V to 2.4V 1
Rate
41
41
4 V/ns
t_F
Output Fall Edge Measured from 2.4V to 0.4V 1
41
41
4 V/ns
Rate
t_D
Duty Cycle
Measured on rising and falling 45
55 45
55 45
55 %
edge at 1.5V
t_JC
Jitter,
Measured on rising edge at
Cycle-to-Cycle 1.5V. Maximum difference of
cycle time between two adja-
cent cycles.
250
250
250 ps
t_SK
Output Skew
Measured on rising and falling
250
250
250 ps
edge at 1.5V
t_PD
Propagation
Measured from SDRAMIN
3.7
3.7
3.7
ns
Delay
Z_o
AC output
Average value during switching
15
15
15
Ω
Impedance
transition. Used for determin-
ing series termination value.
REF0:1 Clock Outputs (Lump Capacitance Test Load = 20 pF)
Parameter
Description
Test Condition/Comments
f
Frequency, Actual
Frequency generated by crystal oscillator
t_R
Output Rise Edge Rate Measured from 0.4V to 2.4V
t_F
Output Fall Edge Rate Measured from 2.4V to 0.4V
t_D
Duty Cycle
Measured on rising and falling edge at 1.5V.
f_ST
Frequency Stabilization Assumes full supply voltage reached within 1 ms from
from Power-up (cold power-up. Short cycles exist prior to frequency stabili-
start)
zation.
Z_o
AC Output Impedance Average value during switching transition. Used for de-
termining series termination value.
Min.
0.5
0.5
45
Typ. Max.
14.318
2
2
55
3
40
Unit
MHz
V/ns
V/ns
%
ms
Ω
12