109
XMEGA A4U [DATASHEET]
Atmel-8387G-AVR-ATxmega16A4U-34A4U-64A4U-128A4U-Datasheet_03/2014
36.2.14.8 External 32.768kHz crystal oscillator and TOSC characteristics
Table 36-62. External 32.768kHz crystal oscillator and TOSC characteristics.
Note:
1.
Figure 36-11.TOSC input capacitance.
The parasitic capacitance between the TOSC pins is CL1 + CL2 in series as seen from the crystal when oscillating
without external capacitors.
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
CTOSC1
Parasitic capacitance TOSC1 pin
5.4
pF
Alternate TOSC location
4.0
CTOSC2
Parasitic capacitance TOSC2 pin
7.1
pF
Alternate TOSC location
4.0
Recommended safety factor
capacitance load matched to
crystal specification
3.0
CL1
CL2
2
C
S
O
T
1
C
S
O
T
Device internal
External
32.768kHz crystal
