Datasheet

Figure 54-7. Oscillator Crystal Connection
XIN32
CLEXT
CLEXT
CM
RM
LM
CSHUNT
XOUT32
DEVICE
Crystal
The user must choose a crystal oscillator where the crystal load capacitance C
L
is within the range given
in the table. The exact value of C
L
can be found in the crystal data sheet. The capacitance of the external
capacitors (C
LEXT
) can then be computed as follows:
C
LEXT
= 2 * (C
L
- C
PARA
- C
PCB
- C
SHUNT
)
Where:
• C
PARA
is the internal load capacitor parasitic between XIN32 and XOUT32 and can be computed as
following:
Equation 54-2.


=

32
* 
32

32
+ 
32
• C
PCB
is the capacitance of the PCB
• C
SHUNT
is the shunt capacitance of the crystal as specified by the crystal manufacturer
Table 54-47. 32 kHz Crystal Oscillator Electrical Characteristics
Symbol
Parameter Conditions Min. Typ. Max. Units
F
OUT
(1)
Crystal oscillator frequency - - 32.768 - kHz
CL
(1)
Crystal load capacitance - - - 12.5 pF
C
SHUNT
(1)
Crystal shunt capacitance - - - 1.7 pF
C
M
(1)
Motional capacitance - 2 - 7 fF
ESR Crystal Equivalent Series Resistance -
SF=3
f=32.768
kHz,
C
L
=12.5
pF
Std. Gain - - 58 kΩ
High Gain - - 90
C
XIN32k
Parasitic load capacitor - - 3.1 - pF
C
XOUT32k
- - 3.2 -
t
STARTUP
Startup time f=32.768
kHz,
C
L
=12.5
pF,
C
M
=2.0 fF
Std. Gain - 12 28 kCycles
High Gain - 9 23
Note:
1. These values are based on simulation. They are not covered by production test limits or
characterization.
SAM D5x/E5x Family Data Sheet
Electrical Characteristics at 85°C
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 2015