PIC16C774T-I/SO View Datasheet(PDF) - Microchip Technology
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PIC16C774T-I/SO Datasheet PDF : 202 Pages
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FIGURE 12-2: CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
OSC CONFIGURATION)
C1(1)
OSC1
XTAL
OSC2
RS(2)
C2(1)
RF(3)
To
internal
logic
SLEEP
PIC16C77X
Note1:
2:
3:
See Table 12-1 and Table 12-2 for recom-
mended values of C1 and C2.
A series resistor (RS) may be required for
AT strip cut crystals.
RF varies with the crystal chosen.
FIGURE 12-3: EXTERNAL CLOCK INPUT
OPERATION (HS OSC
CONFIGURATION)
Clock from
ext. system
Open
OSC1
PIC16C77X
OSC2
TABLE 12-1 CERAMIC RESONATORS
Ranges Tested:
Mode
Freq
OSC1
OSC2
XT
455 kHz 68 - 100 pF 68 - 100 pF
2.0 MHz 15 - 68 pF 15 - 68 pF
4.0 MHz 15 - 68 pF 15 - 68 pF
HS
8.0 MHz 10 - 68 pF 10 - 68 pF
16.0 MHz 10 - 22 pF 10 - 22 pF
These values are for design guidance only. See
notes at bottom of page.
Resonators Used:
455 kHz Panasonic EFO-A455K04B 0.3%
2.0 MHz Murata Erie CSA2.00MG 0.5%
4.0 MHz Murata Erie CSA4.00MG 0.5%
8.0 MHz Murata Erie CSA8.00MT 0.5%
16.0 MHz Murata Erie CSA16.00MX 0.5%
All resonators used did not have built-in capacitors.
PIC16C77X
TABLE 12-2 CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Osc Type
Crystal
Freq
Cap. Range Cap. Range
C1
C2
LP
32 kHz
33 pF
33 pF
200 kHz
15 pF
15 pF
XT
200 kHz
47-68 pF
47-68 pF
1 MHz
15 pF
15 pF
4 MHz
15 pF
15 pF
HS
4 MHz
15 pF
15 pF
8 MHz
15-33 pF
15-33 pF
20 MHz
15-33 pF
15-33 pF
These values are for design guidance only. See
notes at bottom of page.
Crystals Used
32 kHz Epson C-001R32.768K-A
± 20 PPM
200 kHz STD XTL 200.000KHz
± 20 PPM
1 MHz ECS ECS-10-13-1
± 50 PPM
4 MHz ECS ECS-40-20-1
± 50 PPM
8 MHz EPSON CA-301 8.000M-C ± 30 PPM
20 MHz EPSON CA-301 20.000M-C ± 30 PPM
Note 1: Recommended values of C1 and C2 are
identical to the ranges tested (Table 12-1).
2: Higher capacitance increases the stability
of oscillator but also increases the start-up
time.
3: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropri-
ate values of external components.
4: Rs may be required in HS mode as well as
XT mode to avoid overdriving crystals with
low drive level specification.
1999-2013 Microchip Technology Inc.
Advance Information
DS30275B-page 129
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