SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 1088

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

40.4.9
40.4.9.1
40.4.9.2
1088
1088
SAM3S8/SD8
SAM3S8/SD8
Crystal Oscillators Design Consideration Information
Choosing a Crystal
Printed Circuit Board (PCB)
When choosing a crystal for the 32768 Hz Slow Clock Oscillator or for the 3-20 MHz Oscillator,
several parameters must be taken into account. Important parameters between crystal and
SAM3S specifications are as follows:
SAM3S Oscillators are low power oscillators requiring particular attention when designing PCB
systems.
• Load Capacitance
• Drive Level
• Equivalent Series Resistor (ESR)
• Shunt Capacitance
– C
– Crystal drive level >= Oscillator Drive Level. Having a crystal drive level number
– Crystal ESR <= Oscillator ESR Max. Having a crystal with ESR value higher than
– Max. crystal Shunt capacitance <= Oscillator Shunt Capacitance (
order to oscillate at the target frequency. The crystal must be chosen according to
the internal load capacitance (C
load capacitance will result in a frequency drift.
lower than the oscillator specification may damage the crystal.
the oscillator may cause the oscillator to not start.
crystal with ESR value higher than the oscillator may cause the oscillator to not start.
crystal
is the equivalent capacitor value the oscillator must “show” to the crystal in
L
) of the on-chip oscillator. Having a mismatch for the
C
SHUNT
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
).
Having a