Datasheet

1125
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
44.5.5 3 to 20 MHz Crystal Oscillator Characteristics
Notes: 1. R
S
is the series resistor
2. Rs = 100–200 Ohms; Cs = 2.0–2.5 pF; Cm = 2–1.5 fF(typ, worst case) using 1 KΩ serial resistor on XOUT.
3. Rs = 50–100 Ohms; Cs = 2.0–2.5 pF; Cm = 4–3 fF(typ, worst case).
4. Rs = 25–50 Ohms; Cs = 2.5–3.0 pF; Cm = 7–5 fF (typ, worst case).
5. Rs = 20–50 Ohms; Cs = 3.2–4.0 pF; Cm = 10–8 fF(typ, worst case).
C
LEXT
= 2 x (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 SAM4 pin.
Table 44-28. 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
Duty Cycle 40 50 60 %
t
ON
Startup Time
3 MHz, C
SHUNT
= 3 pF
8 MHz, C
SHUNT
= 7 pF
16 MHz, C
SHUNT
= 7 pF with Cm = 8 fF
16 MHz, C
SHUNT
= 7 pF with Cm = 1.6 fF
20 MHz, C
SHUNT
= 7 pF
——
14.5
4
1.4
2.5
1
ms
I
DD_ON
Current Consumption
(on VDDIO)
3 MHz
(2)
8 MHz
(3)
16 MHz
(4)
20 MHz
(5)
—
230
300
390
450
350
400
470
560
µA
P
ON
Drive Level
3 MHz
8 MHz
16 MHz, 20 MHz
——
15
30
50
µW
R
f
Internal Resistor Between XIN and XOUT — 0.5 — MΩ
C
LEXT
Maximum External Capacitor
on XIN and XOUT
— — 17 pF
C
L
Internal Equivalent Load Capacitance
Integrated load capacitance
(XIN and XOUT in series)
7.5 9.5 10.5 pF
XIN
XOUT
C
LEXT
C
L
C
LEXT
C
Crystal
SAM4
R = 1K if Crystal Frequency
is lower than 8 MHz