Datasheet

714
11011B–ATARM–21-Feb-12
SAM3N
35.4.6 3 to 20 MHz Crystal Oscillator Characteristics
Notes: 1. R
S
is the series resistor
2. Rs = 100-200 Ohms; Cs = 2.0 - 2.5pF; Cm = 2 – 1.5 fF(typ, worst case) using 1 KΩ serial resistor on XOUT.
3. Rs = 50-100 Ohms; Cs = 2.0 - 2.5pF; Cm = 4 - 3 fF(typ, worst case).
4. Rs = 25-50 Ohms; Cs = 2.5 - 3.0pF; Cm = 7 - 5 fF (typ, worst case).
5. Rs = 20-50 Ohms; Cs = 3.2 - 4.0pF; Cm = 10 - 8 fF(typ, worst case).
C
LEXT
= 2x(C
CRYSTAL
– C
L
– C
PCB
)
Where
C
PCB
is the capacitance of the printed circuit board (PCB) track layout from the crystal to the SAM3 pin.
Table 35-24. 3 to 20 MHz Crystal Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
F
req
Operating Frequency Normal mode with crystal 3 16 20 MHz
F
req_bypass
Operating Frequency In Bypass Mode External Clock on XIN 50 MHz
Supply Ripple Voltage (on VDDPLL) Rms value, 10 KHz to 10 MHz 30 mV
Duty Cycle 40 50 60 %
T
ON
Startup Time
3 MHz, C
SHUNT
= 3pF
8 MHz, C
SHUNT
= 7pF
12 to 16 MHz, C
SHUNT
= 7pF
20 MHz, C
SHUNT
= 7pF
14.5
4
1.4
1
ms
I
DD_ON
Current consumption
3 MHz
(2)
8 MHz
(3)
12 to 16 MHz
(4)
20 MHz
(5)
150
200
250
350
230
300
350
450
µA
P
ON
Drive level
3 MHz
8 MHz
12 MHz, 16 MHz, 20 MHz
15
30
50
µW
R
f
Internal resistor between XIN and XOUT 1 MΩ
C
LEXT
Maximum external capacitor
on XIN and XOUT
12.5 17.5 pF
C
L
Internal Equivalent Load Capacitance
Integrated Load Capacitance
(XIN and XOUT in series)
7.5 9.5 11.5 pF
XIN
XOUT
C
LEXT
C
L
C
LEXT
C
Crystal
SAM3
R=1K if Crystal Frequency
is lower than 8MHz