• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 23 subscribers
  • Views 498 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMX2492EVM: EVAL board has no clock output.

Jimmy Chou40
Prodigy 110 points

Part Number: LMX2492EVM
Other Parts Discussed in Thread: LMX2492

Hi :

I'm testing a LMx2492 EVM, I mounted R27 & R28 to use on board OSC. I'm trying to use TICS pro to generate a fixes clock output. I change PLL page VCO value, but no clock output at RFout & RFout/2.

1 checked board signals. SPI looks good, CE=high,  VccPLL=3.3V, VccCP=5V, but Vtune only 400mV. Please check if something I need to change on board or TICS S/W.

I suppose it should always have a clock output. If I change VCO value on TICS, RFout will change right away, correct?

Thanks

Jimmy

  • 0
    TI__Guru** 120060 points
    Hi Jimmy,

    If you use the "Default configuration", do you get anything from the EVM?
  • 0 in reply to Noel Fung
    Prodigy 110 points

    No, but I've already found the reason.

    In TICS Default configuration, VCO = 9600MHz. But I found RFVC1843 range is from 9.8GHz to 11.3GHz. PLL can't lock under 9.8GHz, so no clock output.

    If I change VCO > 9800MHz in TICS, then RFout has output.

    This EVM can only output up to 10GHz, due to RFVC1843  Vtune is 0~15V, Vtune at 10GHz is already 5V = VccCP,  PLL can't lock over 10GHz.

    Best Regards

    Jimmy