CDC960 Datasheet, PDF (34/38 Pages) Texas Instruments – 200-MHz CLOCK SYNTHESIZER/DRIVER WITH SPREAD SPECTURM CAPABILITY AND DEVICE CONTROL INTERFACE

CDC960
200ĆMHz CLOCK SYNTHESIZER/DRIVER
WITH SPREAD SPECTRUM CAPABILITY AND DEVICE CONTROL INTERFACE
SCAS675 – APRIL 2002
PARAMETER MEASUREMENT INFORMATION
The common mode voltage is measured single-ended and is the result of the following calculation:
Vocm_(t) = [Vo(CPUT)_(t) + Vo(CPUC)_(t)]/2
tw(l)
tw(h)
Avg.
Avg.
CPUx _Vcm(Max)
Vcm(Min)
CPUx
0 V (GND)
Vcm0
Vcm1
45%
of
t_w(l)
75%
of
t_w(l)
45%
of
t_w(h)
75%
of
t_w(h)
Vcm0 is calculated from the average of Vocm within 45%–75% (region without switching noise) of the pulse while CPUx is in the
LOW state.
Vcm1 is calculated from the average of Vocm within 45%–75% (region without switching noise) of the pulse while CPUx is in the
HIGH state.
Vocm = (Vcm0 + Vcm1)/2
∆Vocm = Vcm0 – Vcm1
a) Static
tw(l)
tw(h)
CPUx _Vcm(Max)
Vcm(Min)
CPUx
0 V (GND)
Vcm0
Vcm1
t = 0 to tw(l)
∆Vocm(t) = MAX (Vcm0(t)) – MIN (Vcm1(t)) and
∆Vocm(t) = MIN (Vcm0(t)) – MAX (Vcm1(t))
b) Dynamic
Figure 12. Common Mode Voltage
t = 0 to tw(h)
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