LMX2694-SEP: Questions about the PLLattinum Sim tool

Tsujimoto Naohiro

Part Number: LMX2694-SEP

Tool/software:

Hello, I am a member of the following group.

I have a question about the PLLattinum Sim tool designed by your company.

After selecting the device (LMX2694-SEP) as shown in the image below, when I set the Loop Filter value, the SNR value is -46.8dBm.

I saved this setting from File⇒Save Design.
When I opened the File⇒Load Design file, the SNR value had changed to -48.1 dBm.
The Loop Filter constant was not changed.
Please tell me why the SNR is changing.

6 months ago

0 Noel Fung 6 months ago

TI__Guru** 110970 points

Hi Naohiro-san,

Looks like this is a bug of the tool.

Every time I load the design, the VCO range is not correct.

Toggling the VCO core from VCO1 --> VCO2 --> VCO1, then every time returns to normal.

I will let the developer knows about this issue.

0 Tsujimoto Naohiro 6 months ago in reply to Noel Fung

Prodigy 20 points

Hallo Noel Fung

So there was a bug. Understood.
Just to confirm, after doing the Load Design file, the value of the VCO core is the correct value when you change the VCO core from VCO1 → VCO2 → VCO1, right?

0 Noel Fung 5 months ago in reply to Tsujimoto Naohiro

TI__Guru** 110970 points

Hi Naohiro-san,

Since the VCO frequency range has changed, I believe the wrong VCO core is loaded. After toggling the core, the tool uses the correct core for the calculation and return the original jitter and SNR.

Clock & timing

Clock & timing forum

LMX2694-SEP: Questions about the PLLattinum Sim tool