Intel N2820 FH8065301616603 Data Sheet

90

Datasheet

There are two crystal oscillators. One for RTC that maintains time and provides initial 
timing reference for power sequencing. The other is for the Integrated Clock, which 
covers clocking for the entire processor.

1.

These are the specifications needed to select a crystal oscillator for the RTC circuit.

2.

Crystal tolerance impacts RTC time. A 10 ppm crystal is recommended for 1.7 s tolerance per day, RTC 

circuit itself contributes addition 10 ppm for a total of 20 ppm in this example.

1.

These are the specifications needed to select a crystal oscillator for the Integrated Clock circuit. Crystal 

must be AT cut, fundamental, parallel resonance.

F

RTC

Frequency

-

32.768

-

kHz

1

T

PPM

Crystal frequency tolerance (see 

notes)

-

-

±50

ppm

1

R

ESR

ESR

-

-

50

kOhm

1

C

X1,2

Capacitance of X1, X2 pins 

pF

1

F

ICLK

Frequency

-

25

-

MHz

1

T

PPM

Crystal frequency tolerance & 

stability

-

-

±30

ppm

1

P

DRIVE

Crystal drive load

-

-

100

uW

1

R

ESR

ESR

-

-

100

Ohm

1

C

LOAD

Crystal load capacitance

18

pF

C

SHUNT

Crystal shunt capacitance

-

-

6

pF

1

C

IN/OUT

Capacitance of oscillator pins 

pF

1