Datasheet

 2018 Microchip Technology Inc. Data Sheet Complete DS40002058A-page 97
ATxmega128A1U/ATxmega64A1U
37.1.14.8 External 32.768kHz crystal oscillator and TOSC characteristics
Table 37-30. External 32.768kHz crystal oscillator and TOSC characteristics.
Note: 1. See Figure 37-4 for definition.
Figure 37-4. 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 4.0
pFC
TOSC2
Parasitic capacitance TOSC2 pin 4.1
C
L
Parasitic capacitance load 2.0
Recommended safety factor Capacitive load matched to crystal specification 3
C
L1
C
L2
2CS
O
T
1
CS
O
T
Device internal
External
32.768kHz crystal