Datasheet

128
XMEGA A3U [DATASHEET]
Atmel-8386D-AVR-ATxmega64A3U-128A3U-192A3U-256A3U–03/2014
36.3.14.8 External 32.768kHz crystal oscillator and TOSC characteristics
Table 36-94. External 32.768kHz crystal oscillator and TOSC characteristics.
Note: 1. See Figure 36-4 for definition.
Figure 36-18.TOSC input capacitance.
The parasitic capacitance between the TOSC pins is C
L1
+ C
L2
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
C
TOSC1
Parasitic capacitance TOSC1 pin 4.2 pF
C
TOSC2
Parasitic capacitance TOSC2 pin 4.3 pF
Recommended safety factor
capacitance load matched to
crystal specification
3
C
L1
C
L2
2CS
O
T
1
CS
O
T
Device internal
External
32.768kHz crystal