Datasheet

MCP2515
DS20001801J-page 56  2003-2019 Microchip Technology Inc.
FIGURE 8-3: EXTERNAL SERIES RESONANT CRYSTAL OSCILLATOR CIRCUIT
(1)
TABLE 8-1: CAPACITOR SELECTION FOR
CERAMIC RESONATORS
TABLE 8-2: CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
330 k
74AS04
74AS04
MCP2510
OSC1
To Other
Devices
XTAL
330 k
74AS04
0.1 mF
Note 1: Duty cycle restrictions must be observed (see Table 13-2).
Typical Capacitor Values Used:
Mode Freq. OSC1 OSC2
HS 8.0 MHz 27 pF 27 pF
16.0 MHz 22 pF 22 pF
Capacitor values are for design guidance only:
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values are not optimized.
Different capacitor values may be required to
produce acceptable oscillator operation. The user
should test the performance of the oscillator over the
expected V
DD
and temperature range for the
application.
See the notes following Table 8-2 for additional
information.
Resonators Used:
4.0 MHz
8.0 MHz
16.0 MHz
Osc
Type
(1,4)
Crystal
Freq.
(2)
Typical Capacitor
Values Tested:
C1 C2
HS 4 MHz 27 pF 27 pF
8 MHz 22 pF 22 pF
20 MHz 15 pF 15 pF
Capacitor values are for design guidance only:
These capacitors were tested with the crystals listed
below for basic start-up and operation. These values
are not optimized.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
V
DD
and temperature range for the application.
See the notes following this table for additional
information.
Crystals Used:
(3)
4.0 MHz
8.0 MHz
20.0 MHz
Note 1: While higher capacitance increases the
stability of the oscillator, it also increases
the start-up time.
2: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for
appropriate values of external components.
3: R
S
may be required to avoid overdriving
crystals with a low drive level specification.
4: Always verify oscillator performance over
the V
DD
and temperature range that is
expected for the application.