ATXMEGA128B1 Datasheet, PDF (84/138 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA B1 Microcontroller

36.14.8 External 32.768kHz crystal oscillator and TOSC characteristics
Table 36-28. External 32.768kHz crystal oscillator and TOSC characteristics.
Symbol Parameter
Condition
Min
Typ
Max Units
ESR/R1
Recommended crystal equivalent
series resistance (ESR)
Crystal load capacitance 6.5pF
Crystal load capacitance 9.0pF
Crystal load capacitance 12.0pF
60
35
k
28
C_{IN_TOSC} Input capacitance between TOSC pins
Normal mode
Low power mode
3.5
pF
3.5
Recommended Safety factor
capacitance load matched to
crystal specification
3
Long term Jitter (SIT)
0
%
Note:
1. See Figure 36-4 on page 84 for definition
Figure 36-4. TOSC input capacitance
TOSC1
C_L1
C_L2
Device internal
External
TOSC2
32.768kHz crystal
The input capacitance between the TOSC pins is C_L1 + C_L2 in series as seen from the crystal when oscillating without
external capacitors.
XMEGA B1 [DATASHEET] 84
8330C–AVR–07/2012