Specifications

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AX5051

13

4.3. AC Characteristics

Crystal Oscillator

SYMBOL

DESCRIPTION

CONDITION

MIN.

TYP.

MAX.

UNIT

Crystal frequency

Note 1, 3

15.5

16

25

MHz

Transconductance oscillator

XTALOSCGM=0000

1

mS

XTALOSCGM=0001

2

XTALOSCGM =0010

default

3

XTALOSCGM =0011

4

XTALOSCGM =0100

5

XTALOSCGM =0101

6

XTALOSCGM =0110

6.5

XTALOSCGM =0111

7

XTALOSCGM =1000

7.5

XTALOSCGM =1001

8

XTALOSCGM =1010

8.5

XTALOSCGM =1011

9

XTALOSCGM =1100

9.5

XTALOSCGM =1101

10

XTALOSCGM =1110

10.5

XTALOSCGM =1111

11

Programmable tuning

capacitors

at pins CLK16N and CLK16P

XTALCAP = 000000

default

2

pF

XTALCAP = 111111

33

pF

Programmable tuning

capacitors, increment per LSB

of XTALCAP

0.5

pF

External clock input

Note 2, 3

15.5

16

25

MHz

Input DC impedance

10

k

Notes

1.

Tolerances and start-up times depend on the crystal used. Depending on the RF frequency and channel spacing the IC must be calibrated

to the exact crystal frequency using the readings of the register TRKFREQ

2.

If an external clock is used, it should be input via an AC coupling at pin CLK16P with the oscillator powered up and XTALCAP=000000

3.

Lower frequencies than 15.5 MHz or higher frequencies than 25 MHz can be used. However not all typical RF frequencies can than be

generated.