• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 3 answers
  • Subscribers 20 subscribers
  • Views 348 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

LMX2572EVM: Question about the loop filter components that are installed on the LMX2752EVM development board

LMX2572EVM: Question about the loop filter components that are installed on the LMX2752EVM development board

Alex OHM
Prodigy 70 points
Part Number: LMX2572EVM

Hi,

I also appear to have a newer revision of the EVM with a built in TCXO reference and different loop filter components

I am hoping you can send the component values of the supplied loop filter values (other than the loop filter bandwidth of 30kHz)

Thanks in advance,

Alex

  • 0
    TI__Guru* 85330 points
    Hi Alex,

    What is the rev. of the board? It is shown in the bottom side of the board.
    could you also provide a photo of the board? Thanks.
  • 0 in reply to Noel Fung
    Prodigy 70 points

    Hi,

    Thank you for the fast reply,

    On the back of the board it says:

    SV601308 - 003 (in sticker)

    Rev B

    I don't have an easy way to send a picture of the board, but I think it's all that's needed

    From what I tested it is about a 30kHz bandwidth Loop Filter @ 3GHz Output (FVco/2) with Reference of 100MHz built in TCXO (Default Configuration from TICS Pro)

    (I don't know the exact phase margin)

    Hope the revision # is enough,

    Alex

  • 0 in reply to Alex OHM
    TI__Mastermind 27641 points
    Alex,

    Do the components match what the EVM instructions say?

    C1_LF = C3_LF = open
    C2_LF = 15 nF
    C4_LF = 2.2 nF
    R2_LF = 330 ohm
    R3_LF=R4_LF = 0 ohm

    The caps are hard to check, but the resistors should be easy to verify.

    Regards,
    Dean
  • 0 in reply to Dean Banerjee
    TI__Guru* 85330 points

    Hi Alex,

    In Rev. B, there were some errors in production, the loop filter was populated with some other values like below:

    Please change it back to what is shown in the EVM user's guide. Sorry for the inconvenient caused.