LMX2571: Calculate the output frequency

Jingtai

Genius 4575 points

Part Number: LMX2571
Other Parts Discussed in Thread: ADS6125

I'm not able to find out how calculate the output frequency from SNAS654A.

Suppose

OSCin=26MHz

Output frequency=20MHz

The synthesizer mode is selected.

Set the value of the output channel divider of R22 register.

Is the VOC frequency divided? If it is . VOC frequency is from 4300 to 5376 MHz. How to determine the VOC frequency.

over 8 years ago

0 Noel Fung over 8 years ago

TI__Guru** 118590 points

Hi Jingtai,

the output is divided down from the VCO, so
VCO = CHDIV1 x CHDIV2 x RFout.
if RFout=20MHz, one of the possible VCO frequencies is 5120MHz.

0 Jingtai over 8 years ago in reply to Noel Fung

Genius 4575 points

Thanks for your support.

CHDIV1 X CHDIV2=5120/20=256

How are CHDIV1 and CHDIV2 determined respectively?

0 Noel Fung over 8 years ago in reply to Jingtai

TI__Guru** 118590 points

Hi Jingtai,
CHDIV1 = 4, 5, 6 or 7
CHDIV2 = 2, 4, 8, 16, 32 or 64

0 Jingtai over 8 years ago in reply to Noel Fung

Genius 4575 points

Thanks for your support!

0 Jingtai over 8 years ago in reply to Noel Fung

Genius 4575 points

Is LMX2571 a correct selection as the input clock of the ADS6125?

0 Noel Fung over 8 years ago in reply to Jingtai

TI__Guru** 118590 points

Yes, they should work together.

0 Jingtai over 8 years ago in reply to Noel Fung

Genius 4575 points

Thank you for the support!

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LMX2571: Calculate the output frequency