PIC16C62B/72A
10.2
Oscillator Configurations
TABLE 10-1
CERAMIC RESONATORS
10.2.1
OSCILLATOR TYPES
Ranges Tested:
The PIC16CXXX can be operated in four different oscil-
lator modes. The user can program two configuration
bits (FOSC1 and FOSC0) to select one of these four
modes:
Mode
XT
Freq
OSC1
OSC2
455 kHz
2.0 MHz
4.0 MHz
68 - 100 pF
15 - 68 pF
15 - 68 pF
68 - 100 pF
15 - 68 pF
15 - 68 pF
• LP
• XT
• HS
• RC
Low Power Crystal
HS
8.0 MHz
16.0 MHz
10 - 68 pF
10 - 22 pF
10 - 68 pF
10 - 22 pF
Crystal/Resonator
These values are for design guidance only. See
notes at bottom of page.
High Speed Crystal/Resonator
Resistor/Capacitor
Resonators Used:
10.2.2 CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
455 kHz Panasonic EFO-A455K04B ± 0.3%
2.0 MHz Murata Erie CSA2.00MG
4.0 MHz Murata Erie CSA4.00MG
8.0 MHz Murata Erie CSA8.00MT
16.0 MHz Murata Erie CSA16.00MX
± 0.5%
± 0.5%
± 0.5%
± 0.5%
In XT, LP or HS modes, a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
pins to establish oscillation (Figure 10-2). The
PIC16CXXX oscillator design requires the use of a par-
allel cut crystal. Use of a series cut crystal may give a
frequency out of the crystal manufacturers specifica-
tions. When in XT, LP or HS modes, the device can use
an external clock source to drive the OSC1/CLKIN pin
(Figure 10-3).
Resonators did not have built-in capacitors.
TABLE 10-2
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Crystal
Freq
Cap. Range
C1
Cap. Range
Osc Type
C2
FIGURE 10-2: CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
LP
32 kHz
200 kHz
200 kHz
1 MHz
33 pF
15 pF
33 pF
15 pF
XT
HS
47-68 pF
15 pF
47-68 pF
15 pF
OSC CONFIGURATION)
C1(1)
4 MHz
15 pF
15 pF
OSC1
4 MHz
15 pF
15 pF
To
internal
8 MHz
15-33 pF
15-33 pF
15-33 pF
15-33 pF
logic
XTAL
RS(2)
RF(3)
20 MHz
OSC2
These values are for design guidance only. See
notes at bottom of page.
SLEEP
PIC16CXXX
C2(1)
Crystals Used
32 kHz
200 kHz
1 MHz
Epson C-001R32.768K-A
STD XTL 200.000KHz
ECS ECS-10-13-1
± 20 PPM
± 20 PPM
± 50 PPM
± 50 PPM
± 30 PPM
± 30 PPM
Note1: See Table 10-1 and Table 10-2 for recom-
mended values of C1 and C2.
2: A series resistor (RS) may be required for
AT strip cut crystals.
3: RF varies with the crystal chosen.
4 MHz
ECS ECS-40-20-1
8 MHz
EPSON CA-301 8.000M-C
EPSON CA-301 20.000M-C
20 MHz
FIGURE 10-3: EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
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 charac-
teristics, the user should consult the resona-
tor/crystal manufacturer for appropriate values of
external components.
OSC CONFIGURATION)
OSC1
OSC2
Clock from
ext. system
PIC16CXXX
Open
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 when
migrating between devices (including
PIC16C62A to PIC16C62B and PIC16C72 to
PIC16C72A)
DS35008B-page 56
Preliminary
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
