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LMX25312265EVAL: EVM is not drawing any current form 3V Vcc

Pradeep Kumar68
Intellectual 420 points
Part Number: LMX25312265EVAL
Other Parts Discussed in Thread: USB2ANY, LMX2531

I am using LMX2531LQ2265E EVM to generate 2255.5MHz from 25MHz clock reference. I have fed 3V Vcc to EVM. I feeding 25MHz@8dBm sinewave ref clock from Agilent signal generator.

This EVM has to draw around 40-50mA current. But when I switch on power supply, EVM is not drawing any current form 3V Vcc.

Then I tried to program the device using code-loader, But device is not at all responding. I also tried using Tics-pro. But same problem occurred.

I measured Voltage on EVM, they are correct. CE is 2V(once I load register from code-loader). But I am not geeting any output from EVM.

I using internal Loop filter. And my registers setting are as below.

R5 (INIT1) 0x840005
R5 (INIT2) 0x800005
R5 0x8007F5
R12 0x01048C
R9 0x000BA9
R8 0x028008
R7 0x019207
R6 0x168006
R4 0x3C0004
R3 0x6CC0C3
R2 0x4D4012
R1 0x3E0021
R0 0x5AAF80

Please help.

  • 0
    TI__Expert 7845 points
    Hi Pradeep,

    The power supply is a good first debug step. If there is no current at all, I'd check the routing on the EVM. Are all the jumpers for the Vcc connected? If a power supply is connected to the device and nothing else done, there should be about 12mA flowing into the device's digital circuitry.

    regards,

    Brian Wang
  • 0 in reply to Brian Wang
    Intellectual 420 points

    Hello Brian,

    All jumpers are placed correctly. I am measuring 3V at R2,R3,R4 and R5. Also I am measuring 3V across C9,C12,C18 and C17. So routing should be good.

    It is absolutely not drawing any current. So we have no clue about what is going on.

    I hope this EVM is tested at TI lab.?

    Is there could be any soldering issues.?

  • 0 in reply to Pradeep Kumar68
    TI__Mastermind 27581 points

    Pradeep,

    I would first start debugging the SPI bus.  First of all, the CE pin should be high as it seems like the device might be powered down.

    Also, the LMX2531EVM boards is an older one created before the USB2ANY interface.  I believe that this board needs a converter board to work with USB2ANY.  What I would do is as follows:

    1.Ensure the CE pin is high.  If not, you can tie it high with a resistor and eliminate this variable from teh debugging.

    2. Try programming the device and checking the current using powerdown bit.

    3.  Ensure you see signals on the CLK, DATA, and LE pins for the SPI.

    Regardsl

    Dean

  • 0 in reply to Dean Banerjee
    Intellectual 420 points

    Hello sir,

    CE will be low initially, but once we programme, CE is going high. So no issue with CE.

    My concern is also about SPI interface, as per EVM guide. there is a interface card between USB2ANY module to EVM board. So I connected it.

    When I probed on SPI line, I could see only Clk, and LE. But data line was always low. 

    Since we don't know the USB2ANY output pin details, we could not able figure out from where to where signals are flowing.

    Regards,

    Pradeep

  • 0 in reply to Pradeep Kumar68
    TI__Expert 7845 points

    Pradeep,

    If there is no data line that may be it. Do you have the interface card connected like the attached document (see the table of jumper requirements for LMX2531)?

    USB2ANY_UWIRE_users_guide.docx