Datasheet

1046
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
46.5 Main Oscillator Characteristics
Note: 1. The C
CRYSTAL
value is specified by the crystal manufacturer. In our case, C
CRYSTAL
must be between 15 pF and 20 pF.
All parasitic capacitance, package and board, must be calculated in order to reach 15 pF (minimum targeted load for
the oscillator) by taking into account the internal load C
INT
. So, to target the minimum oscillator load of 15 pF, external
capacitance must be: 15 pF - 4 pF = 11 pF which means that 22 pF is the target value (22 pF from xin to gnd and 22
pF from xout to gnd). If 20 pF load is targeted, the sum of pad, package, board and external capacitances must be 20
pF - 4 pF = 16 pF which means 32 pF (32 pF from xin to gnd and 32 pF from xout to gnd).
Table 46-7. Main Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
1/(t
CPMAIN
) Crystal Oscillator Frequency 12 16 MHz
C
CRYSTAL
(1)
Crystal Load Capacitance 15 20 pF
C
LEXT
External Load Capacitance
C
CRYSTAL
= 15 pF
(1)
27 pF
C
CRYSTAL
= 20 pF
(1)
32 pF
Duty Cycle 40 60 %
t
ST
Startup Time 2ms
I
DDST
Standby Current Consumption Standby mode 1 μA
P
ON
Drive Level 150 μW
I
DD ON
Current Dissipation
@ 12 MHz 0.52 0.55 mA
@ 16 MHz 0.7 1.1 mA
1K
XIN XOUT
GNDPLL
C
LEXT
C
LEXT
C
CRYSTAL