Datasheet

SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
680
38.5 Crystal Oscillator Characteristics
The following characteristics are applicable to the operating temperature range: T
A
= -40°C to 85°C and worst case of
power supply, unless otherwise specified.
38.5.1 32 kHz Oscillator Characteristics
Notes: 1. R
S
is the equivalent series resistance, C
L
is the equivalent load capacitance.
2. C
LEXT32
is determined by taking into account internal parasitic and package load capacitance.
3. Additional user load capacitance should be subtracted from C
LEXT32
.
Figure 38-2. 32 kHz Oscillator Schematic
38.5.2 32 kHz Crystal Characteristics
Table 38-8. 32 kHz Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
1/(t
CP32KHz
) Crystal Oscillator Frequency – – 32.768 – kHz
C
CRYSTAL32
Crystal Load Capacitance Crystal @ 32.768 kHz 6 – 12.5 pF
C
LEXT32
(2)
External Load Capacitance
C
CRYSTAL32
= 6 pF
(3)
–4–
pF
C
CRYSTAL32
= 12.5 pF
(3)
–17–
– Duty Cycle – 40 60 %
t
START
Startup Time
V
DDBU
= 1.2V
R
S
= 50 kΩ, C
L
= 6 pF
(1)
––400
ms
V
DDBU
= 1.2V
R
S
= 50 kΩ, C
L
= 12.5 pF
(1)
––900
V
DDBU
= 1.2V
R
S
= 100 kΩ, C
L
= 6 pF
(1)
––600
V
DDBU
= 1.2V
R
S
= 100 kΩ, C
L
= 12.5 pF
(1)
– – 1200
XIN32 XOUT32 GNDBU
C
LEXT32
C
LEXT32
C
CRYSTAL32
Table 38-9. 32 kHz Crystal Characteristics
Symbol Parameter Conditions Min Typ Max Unit
ESR Equivalent Series Resistor Rs Crystal @ 32.768 kHz – 50 100 kΩ
C
m
Motional Capacitance Crystal @ 32.768 kHz – – 3 fF
C
SHUNT
Shunt Capacitance Crystal @ 32.768 kHz – – 2 pF