Datasheet

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588
Atmel | SMART SAM D20 [DATASHEET]
Atmel-42129K–SAM-D20_datasheet–06/2014
32.10.2 External 32kHz Crystal Oscillator (XOSC32K) Characteristics
32.10.2.1 Digital Clock Characteristics
The following table describes the characteristics for the oscillator when a digital clock is applied on XIN32 pin.
Table 32-35. Digital Clock Characteristics
32.10.2.2 Crystal Oscillator Characteristics
Figure 32-4 and the equation in “Crystal Oscillator Characteristics” on page 586 also applies to the 32kHz oscillator
connection. 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 datasheet.
Note: 1. See revD/revC/revB errata concerning the XOSC32K.
32.10.3 Digital Frequency Locked Loop (DFLL48M) Characteristics
Table 32-37. DFLL48M Characteristics
(2)
Symbol Parameter Conditions Min. Typ. Max. Units
f
CPXIN32
XIN32 clock frequency
I
- 32.768 - kHz
I
XIN32 clock duty cycle
I
- 50 - %
Table 32-36. 32kHz Crystal Oscillator Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units
f
OUT
Crystal oscillator frequency
I
- 32768 - Hz
t
STARTUP
Startup time ESR
XTAL
= 39.9kΩ, C
L
= 12.5pF - 28K 30K cycles
C
L
Crystal load capacitance
I
- - 12.5
pF
C
SHUNT
Crystal shunt capacitance
I
- 0.1 -
C
XIN32
Parasitic capacitor load
TQFP64/48/32 packages
- 3.1 -
C
XOUT32
Parasitic capacitor load - 3.3 -
I
XOSC32K
Current consumption
AGC off - 1.22 2.19
µA
AGC on
(1)
- - -
ESR
Crystal equivalent series
resistance f=32.768kHz
Safety Factor = 3
C
L
=12.5pF - - 141 kΩ
Symbol Parameter Conditions Min. Typ. Max. Units
f
OUT
Output frequency
I
Open loop after calibration at
room temperature
47 48 49 MHz
f
REF
Reference frequency
I
0.732 32.768 33 kHz
Maximum fine step size
(1)
Open loop - - 0.15
%
Maximum coarse step size
(1)
Open loop - - 2.5