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

Alex OHM

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

over 5 years ago

0 Noel Fung over 5 years ago

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 Alex OHM over 5 years ago 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 Dean Banerjee over 5 years ago 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 Noel Fung over 5 years ago 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.

Clock & timing

Clock & timing forum

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