
154
XMEGA C3 [DATASHEET]
8492F–AVR–07/2013
Note:
1.
Numbers for negative impedance are not tested in production but guaranteed from design and characterization.
33.5.13.8 External 32.768kHz crystal oscillator and TOSC characteristics
Table 33-143.External 32.768kHz crystal oscillator and TOSC characteristics.
Note:
Figure 33-32.TOSC input capacitance.
The parasitic capacitance between the TOSC pins is C
L1 + CL2 in series as seen from the crystal when oscillating without
external capacitors.
C
XTAL1
Parasitic capacitance
XTAL1 pin
5.9
pF
C
XTAL2
Parasitic capacitance
XTAL2 pin
8.3
C
LOAD
Parasitic capacitance load
3.5
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
ESR/R1
Recommended crystal equivalent
series resistance (ESR)
Crystal load capacitance 6.5pF
60
k
Crystal load capacitance 9.0pF
35
Crystal load capacitance 12pF
28
CTOSC1
Parasitic capacitance TOSC1 pin
3.5
pF
CTOSC2
Parasitic capacitance TOSC2 pin
3.5
Recommended safety factor
capacitance load matched to
crystal specification
3
CL1
CL2
2
C
S
O
T
1
C
S
O
T
Device internal
External
32.768kHz crystal