PIC16C63A/65B/73B/74B
TABLE 13-1:
Ranges Tested:
Mode
Freq
OSC1
OSC2
CERAMIC RESONATORS
Note 1:
Higher capacitance increases the stability
of the oscillator, but 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 compo-
nents.
3:
Rs may be required in HS mode, as well
as XT mode, to avoid overdriving crystals
with low drive level specification.
4:
Oscillator performance should be verified
at the expected voltage and temperature
extremes in which the application is
expected to operate.
XT
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
16.0 MHz
68 - 100 pF
15 - 68 pF
15 - 68 pF
10 - 68 pF
10 - 22 pF
68 - 100 pF
15 - 68 pF
15 - 68 pF
10 - 68 pF
10 - 22 pF
HS
Note:
These values are for design guidance only.
See notes following Table 13-1 and Table 13-2.
Resonators Used:
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
16.0 MHz
Note:
Panasonic EFO-A455K04B
Murata Erie CSA2.00MG
Murata Erie CSA4.00MG
Murata Erie CSA8.00MT
Murata Erie CSA16.00MX
± 0.3%
± 0.5%
± 0.5%
± 0.5%
± 0.5%
13.2.3
RC OSCILLATOR
Resonators used did not have built-in capacitors.
TABLE 13-2:
Osc Type
LP
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Crystal
Freq
32 kHz
200 kHz
Cap. Range
C1
33 pF
15 pF
47-68 pF
15 pF
15 pF
15 pF
15-33 pF
15-33 pF
Cap. Range
C2
33 pF
15 pF
47-68 pF
15 pF
15 pF
15 pF
15-33 pF
15-33 pF
XT
200 kHz
1 MHz
4 MHz
For timing insensitive applications, the “RC” device
option offers additional cost savings. The RC oscillator
frequency is a function of the supply voltage, the resis-
tor (R
EXT
) and capacitor (C
EXT
) values, and the operat-
ing temperature. The oscillator frequency will vary from
unit to unit due to normal process variation. The differ-
ence in lead frame capacitance between package
types will also affect the oscillation frequency, espe-
cially for low C
EXT
values. The user also needs to take
into account variation due to tolerance of external R
and C components used. Figure 13-3 shows how the
R/C combination is connected to the PIC16CXX.
The oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin, and can be used for test pur-
poses or to synchronize other logic (see Figure 3-2 for
waveform).
HS
4 MHz
8 MHz
20 MHz
FIGURE 13-3:
V
DD
R
EXT
RC OSCILLATOR MODE
Note:
These values are for design guidance only.
See notes following Table 13-1 and Table 13-2.
Crystals Used:
32 kHz
200 kHz
1 MHz
4 MHz
8 MHz
20 MHz
Epson C-001R32.768K-A
STD XTL 200.000KHz
ECS ECS-10-13-1
ECS ECS-40-20-1
EPSON CA-301 8.000M-C
EPSON CA-301 20.000M-C
± 20 PPM
± 20 PPM
± 50 PPM
± 50 PPM
± 30 PPM
± 30 PPM
OSC1
C
EXT
V
SS
F
OSC
/4
OSC2/CLKOUT
Internal
Clock
PIC16CXX
Recommended Values: R
EXT
= 3 kW to 100 kW
C
EXT
= 20 pf to 30 pF
2000 Microchip Technology Inc.
DS30605C-page 87
MICROCHIP [ MICROCHIP TECHNOLOGY ]
