Clock Generator Module (CGMC)
Acquisition/Lock Time Specifications
MC68HC908GP32
•
MC68HC08GP32
—
Rev. 6
Technical Data
MOTOROLA
Clock Generator Module (CGMC)
135
filter capacitor, filter capacitor leakage, stray impedances on the circuit
board, and even humidity or circuit board contamination.
7.9.3 Choosing a Filter
As described in
7.9.2 Parametric Influences on Reaction Time
, the
external filter network is critical to the stability and reaction time of the
PLL. The PLL is also dependent on reference frequency and supply
voltage.
Either of the filter networks in
Figure 7-10
is recommended when using
a 32.768kHz reference crystal.
Figure 7-10
(a)
is used for applications
requiring better stability.
Figure 7-10
(b)
is used in low-cost applications
where stability is not critical.
Figure 7-10. PLL Filter
10 k
Ω
0.01
µ
F
0.033
µ
F
V
SSA
0.47
µ
F
V
SSA
(a)
(b)
CGMXFC
CGMXFC
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..