Datasheet

1433
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
Figure 47-12. 3 to 20 MHz Crystal Oscillator Schematics
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 SAM4 pin.
47.4.6 3 to 20 MHz Crystal Characteristics
47.4.7 3 to 20 MHz XIN Clock Input Characteristics in Bypass Mode
Note: 1. These characteristics apply only when the 3-20 MHz crystal oscillator is in Bypass mode.
XIN
XOUT
C
LEXT
C
L
C
LEXT
C
CRYSTAL
SAM4
R = 1kΩ if Crystal Frequency
is lower than 8 MHz
Table 47-21. Crystal Characteristics
Symbol Parameter Conditions Min Typ Max Unit
ESR Equivalent Series Resistor (R
S
)
Fundamental @ 3 MHz
Fundamental @ 8 MHz
Fundamental @ 12 MHz
Fundamental @ 16 MHz
Fundamental @ 20 MHz
—
—
—
—
—
—
—
—
—
—
200
100
80
80
50
Ω
C
M
Motional capacitance — — — 8 fF
C
SHUNT
Shunt capacitance — — — 7 pF
Table 47-22. XIN Clock Electrical Characteristics (In Bypass Mode)
Symbol Parameter Conditions Min Typ Max Units
1/(t
CPXIN
) XIN Clock Frequency
(1)
——50 MHz
t
CPXIN
XIN Clock Period
(1)
20 — — ns
t
CHXIN
XIN Clock High Half-period
(1)
8—— ns
t
CLXIN
XIN Clock Low Half-period
(1)
8—— ns
t
CLCH
Rise Time
(1)
2.2 — — ns
t
CHCL
Fall Time
(1)
2.2 — — ns
V
XIN_IL
V
XIN
Low-level Input Voltage
(1)
-0.3 —
MIN
[0.8V,0.3 x V
VDDIO
]
V
V
XIN_IH
V
XIN
High-level Input Voltage
(1)
MIN
[2.0V,0.7 x V
VDDIO
]
—V
VDDIO
+0.3V V