LMX2594EVM: Wrong read back @ +75°C

user5941540

Part Number: LMX2594EVM

Hi,

I have an issue when I want to readback the R110 register (rb_LD_VTUNE) in order to know the state of the LMX. I'm using my own script to control the LMX which works correctly.

When I go over +60°C, the R110 register give me only two answer: 0 or 1. I'm still investigating on this problem (maybe it's my script but I'm confident about it), but I would like to know if you already notice this problem and if you have a solution ?

Thanks

Stéphane

over 5 years ago

0 Noel Fung over 5 years ago

TI__Guru** 108550 points

Hi Stephane,

Did you mean you got either 0x0 or 0x1 instead of 0x2 (= locked)? If you configure MUXout to lock detect output, did it say lock? What is the setting for LD_DLY?

0 user5941540 over 5 years ago in reply to Noel Fung

Intellectual 280 points

Hi Noel,

That's right, I don't read 0x2 (or even 0x3), whereas the LMX is locked (Lock Detect is high for the same configuration). I do not use the LD_DLY, so this parameter is equal to 0.

0 Noel Fung over 5 years ago in reply to user5941540

TI__Guru** 108550 points

Hi Stephane,

As far as I know, the lock detect algorithm between R110 and MUXOUT is different. MUXOUT reflects the true lock state accurately if you have made LD_TYPE = 1. I don't know, maybe if you re-calibrate the part at 60C, R110 will report lock again.

0 user5941540 over 5 years ago in reply to Noel Fung

Intellectual 280 points

Hi Noel,

Finally, I've found the problem: the SPI link is sensitive to the temperature. Lowering the clock speed resolves the problem. I'm sorry for the disturbance, that was my fault.

Regards,

Stéphane

Clock & timing

Clock & timing forum

LMX2594EVM: Wrong read back @ +75°C