LMX2541: Register programming after power down

Brian Antheunisse

Part Number: LMX2541
Other Parts Discussed in Thread: LMX2531

Hi team,

I have a customer using the LMX2541 and LMX2531 on a project, and they have a few questions.

I believe If you cycle chip enable on the synthesizers, you have to reprogram the registers. Is that correct?

It looks like from the Code Loader software that the LMX2541 has a power down feature. If we use that do we have to reprogram the registers afterward?

If yes, is there a similar feature on the LMX2531 part?

Thanks,

Brian

over 7 years ago

0 Noel Fung over 7 years ago

TI__Guru** 109630 points

Hi Brian,

assume you have both devices locked. now if you pull their CE pins low, they will be powered down. When you pull the CE pins back to HIGH, both devices will lock to the previous configuration.
LMX2541 can be soft power down/up, again it will lock to the previous configuration after resuming from powerdown.
LMX2531 can only be power down/up using the CE pin.

0 Brian Antheunisse over 7 years ago in reply to Noel Fung

TI__Expert 5305 points

Noel,

That answered my question, sorry for not marking it resolved.

One final question before I close the thread. Is there a minimum delay requirement between assertion of chip enable and starting to program the synthesizers?

Thanks,
Brian

0 Noel Fung over 7 years ago in reply to Brian Antheunisse

TI__Guru** 109630 points

Hi Brian,

I would recommend wait 100µs before programming the device.

Clock & timing

Clock & timing forum

LMX2541: Register programming after power down