LMX2582: Is Phase programmable in integer mode?

Shengyue Zhong

Part Number: LMX2582

Hi Team,

I have a question for LMX2582, is phase programmable in integer mode? Like 40MHz input, and the output is the same frequency, but phase is shifted? And what’s the relationship between input and output? Thanks a lot!

over 1 year ago

0 vicente flores prado over 1 year ago

TI__Mastermind 29272 points

Hi Shengyue,
Phase adjustment is only possible in fractional mode.

You can have a 40 MHz input and 40 MHz output in fractional mode as well:

Regards,

Vicente

0 Shengyue Zhong over 1 year ago in reply to vicente flores prado

TI__Intellectual 1290 points

Hi Vicente,

another two questions,

1. When Fnumerator is written as 0, is this an integer division? For example, what is the difference between 48+0/1000 and 47+1000/1000?

2. Can the phase move forward and backward both? Or just one direction, by reset the value of Mash_seed

0 vicente flores prado over 1 year ago in reply to Shengyue Zhong

TI__Mastermind 29272 points

Hi Shengyue,
IF you have N = 48 with no fractional component; you are operating in integer mode which does not use the sigma delta modulator.

47 + 1k/1k will use the sigma delta modulator given it is used for fractional N divider values

Correct, phase adjustment will be in one direction only.

Regards,

Vicente

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LMX2582: Is Phase programmable in integer mode?