Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

1434

When choosing a crystal for the 32.768 kHz Slow Clock Oscillator or for the 3-20 MHz Oscillator, several
parameters must be taken into account. Important parameters between crystal and SAM4E specifications are as
follows:



Load Capacitance

̶

C

CRYSTAL

 is the equivalent capacitor value the oscillator must “show” to the crystal in order to oscillate 

at the target frequency. The crystal must be chosen according to the internal load capacitance (C

L

) of 

the on-chip oscillator. Having a mismatch for the load capacitance will result in a frequency drift.



Drive Level

̶

Crystal drive level 

≥ Oscillator Drive Level. Having a crystal drive level number lower than the oscillator 

specification may damage the crystal.



Equivalent Series Resistor (ESR)

̶

Crystal ESR 

≤ Oscillator ESR Max. Having a crystal with ESR value higher than the oscillator may 

cause the oscillator to not start.



Shunt Capacitance

̶

Max. crystal Shunt capacitance 

≤ Oscillator Shunt Capacitance (

C

SHUNT

). 

Having a crystal with ESR 

value higher than the oscillator may cause the oscillator to not start.

SAM4E oscillators are low-power oscillators requiring particular attention when designing PCB systems.

VDDPLL

Supply Voltage Range

1.08

1.2

1.32

V

Allowable Voltage Ripple

RMS value 10 kHz to 10 MHz

RMS value > 10 MHz

—

—

—

—

20

10

mV

f

IN

Input Frequency

—

3

—

32

MHz

f

OUT

Output Frequency

—

80

—

240

MHz

I

PLL

Current Consumption

Active mode @ 80 MHz @1.2V

Active mode @ 96 MHz @1.2V

Active mode @ 160 MHz @1.2V

Active Mode @ 240 MHz @1.2V

—

—

—

—

0.94

1.2

2.1

3.34

1.2

1.5

2.5

4

mA

t

S

Settling Time

—

—

60

150

µs