mc68hc08qa24 Freescale Semiconductor, Inc, mc68hc08qa24 Datasheet - Page 130

• Manufacturer Part Number: mc68hc08qa24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Clock Generator Module (CGM)
9.10.3 Choosing a Filter Capacitor
Technical Data
128
filter capacitor, filter capacitor leakage, stray impedances on the circuit
board, and even humidity or circuit board contamination.
As described in
external filter capacitor, C
the PLL. The PLL is also dependent on reference frequency, f
supply voltage, V
chosen with supply potential and reference frequency in mind. For
proper operation, the external filter capacitor must be chosen according
to the following equation. Refer to
(PLL)
for the value of C
For the value of V
operating. If the power supply is variable, choose a value near the middle
of the range of possible supply values.
This equation does not always yield a commonly available capacitor
size, so round to the nearest available size. If the value is between two
different sizes, choose the higher value for better stability. Choosing the
lower size may seem attractive for acquisition time improvement, but the
PLL can become unstable. Also, always choose a capacitor with a tight
tolerance (±20 percent or better) and low dissipation.
for the value of f
Clock Generator Module (CGM)
9.10.2 Parametric Influences on Reaction
DD
Fact
DDA
. The value of the capacitor, therefore, must be
.
, choose the voltage potential at which the MCU is
C
XCLK
F
F
=
, is critical to the stability and reaction time of
and
C
Fact
23.10 CGM Component Information


9.4.2 Phase-Locked Loop Circuit
V
------------ -
f
XCLK
DDA


Freescale Semiconductor
MC68HC08QA24
Time, the
RDV
, and