MC9S12Q FREESCALE [Freescale Semiconductor, Inc], MC9S12Q Datasheet - Page 619

• Manufacturer Part Number: MC9S12Q
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

The loop bandwidth f
typical values are 50. = 0.9 ensures a good transient response.
And finally the frequency relationship is defined as
With the above values the resistance can be calculated. The example is shown for a loop bandwidth
f
The capacitance C
The capacitance C
A.4.3.2
The basic functionality of the PLL is shown in
deviation from the reference clock f
The adjustment is done continuously with no abrupt changes in the clock output frequency. Noise, voltage,
temperature and other factors cause slight variations in the control loop resulting in a clock jitter. This jitter
affects the real minimum and maximum clock periods as illustrated in
Freescale Semiconductor
C
=10kHz:
R
Jitter Information
=
C
2
---------------------------- -
s
p
s
can now be calculated as:
should be chosen in the range of:
C
f
=
C
K
should be chosen to fulfill the Gardner’s stability criteria by at least a factor of 10,
n
--------------------- -
<
n f
2
C
=
------------------------------------------
f
C
s
C
f
------------ -
VCO
f
2
2
ref
20 C
R
= 2* *50*10kHz/(316.7Hz/ )=9.9k =~10k
+
ref
is measured and input voltage to the VCO is adjusted accordingly.
=
0.516
-------------- -
f
1
f
C
ref
p
+
2
R
2
C
MC9S12Q128
;
Figure
synr
s
Rev 1.09
---- -
10
=
10
1
0.9
+
A-3. With each transition of the clock f
1
f
f
C
C
C
p
= 5.19nF =~ 4.7nF
<
< 25kHz
= 470pF
= 50
------------ -
4 10
f
ref
Figure
;
Appendix A Electrical Characteristics
=
A-4.
0.9
cmp
, the
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