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Original question:

LMX2594: mash_seed usage

LMX2594: output of lmx2594

user5959213
Intellectual 865 points
Part Number: LMX2594


Hi all,

     The lmx2594 on my board which output is above 7.5G ,that's mean the VCO output directly.And i have set outa_mux and outb_mux=VCO even if there is only one channel output.But the output harmonics,in addition to the second and third harmonics, there are also half  output frequencies. The datasheet part 6.5 at page 9 is also not mention this spur when mux=VCO,does that mean there's no such spur at this time?

Thanks.

  • 0
    TI__Guru** 110060 points

    Hi There,

    Did you set R31[14] = 0?

    Can you setup TICS Pro to your configuration, save the file and then send here for us to review?

  • 0 in reply to Noel Fung
    Intellectual 865 points

    Hi Noel,

         Yes,i set R31[14]=0.My configuration is here

    Fullscreen 11288.16M.txt Download 
    lmx2592wr 2,112,0x0000
lmx2592wr 2,111,0x0000
lmx2592wr 2,110,0x0000
lmx2592wr 2,109,0x0000
lmx2592wr 2,108,0x0000
lmx2592wr 2,107,0x0000
lmx2592wr 2,106,0x0000
lmx2592wr 2,105,0x0021
lmx2592wr 2,104,0x0000
lmx2592wr 2,103,0x0000
lmx2592wr 2,102,0x3F80
lmx2592wr 2,101,0x0011
lmx2592wr 2,100,0x0000
lmx2592wr 2,99,0x0000
lmx2592wr 2,98,0x0200
lmx2592wr 2,97,0x0888
lmx2592wr 2,96,0x0000
lmx2592wr 2,95,0x0000
lmx2592wr 2,94,0x0000
lmx2592wr 2,93,0x0000
lmx2592wr 2,92,0x0000
lmx2592wr 2,91,0x0000
lmx2592wr 2,90,0x0000
lmx2592wr 2,89,0x0000
lmx2592wr 2,88,0x0000
lmx2592wr 2,87,0x0000
lmx2592wr 2,86,0x0000
lmx2592wr 2,85,0xD300
lmx2592wr 2,84,0x0001
lmx2592wr 2,83,0x0000
lmx2592wr 2,82,0x1E00
lmx2592wr 2,81,0x0000
lmx2592wr 2,80,0x6666
lmx2592wr 2,79,0x0026
lmx2592wr 2,78,0x00A7
lmx2592wr 2,77,0x0000
lmx2592wr 2,76,0x000C
lmx2592wr 2,75,0x0800
lmx2592wr 2,74,0x0000
lmx2592wr 2,73,0x003F
lmx2592wr 2,72,0x0001
lmx2592wr 2,71,0x0081
lmx2592wr 2,70,0xC350
lmx2592wr 2,69,0x0000
lmx2592wr 2,68,0x03E8
lmx2592wr 2,67,0x0000
lmx2592wr 2,66,0x01F4
lmx2592wr 2,65,0x0000
lmx2592wr 2,64,0x1388
lmx2592wr 2,63,0x0000
lmx2592wr 2,62,0x0322
lmx2592wr 2,61,0x00A8
lmx2592wr 2,60,0x0000
lmx2592wr 2,59,0x0001
lmx2592wr 2,58,0x8001
lmx2592wr 2,57,0x0020
lmx2592wr 2,56,0x0000
lmx2592wr 2,55,0x0000
lmx2592wr 2,54,0x0000
lmx2592wr 2,53,0x0000
lmx2592wr 2,52,0x0820
lmx2592wr 2,51,0x0080
lmx2592wr 2,50,0x0000
lmx2592wr 2,49,0x4180
lmx2592wr 2,48,0x0300
lmx2592wr 2,47,0x0300
lmx2592wr 2,46,0x07FD
lmx2592wr 2,45,0xC8DF
lmx2592wr 2,44,0x1FA3
lmx2592wr 2,43,0xAE60
lmx2592wr 2,42,0x0000
lmx2592wr 2,41,0x0000
lmx2592wr 2,40,0x0000
lmx2592wr 2,39,0xD000
lmx2592wr 2,38,0x0002
lmx2592wr 2,37,0x0304
lmx2592wr 2,36,0x003D
lmx2592wr 2,35,0x0004
lmx2592wr 2,34,0x0000
lmx2592wr 2,33,0x1E21
lmx2592wr 2,32,0x0393
lmx2592wr 2,31,0x03EC
lmx2592wr 2,30,0x318C
lmx2592wr 2,29,0x318C
lmx2592wr 2,28,0x0488
lmx2592wr 2,27,0x0002
lmx2592wr 2,26,0x0DB0
lmx2592wr 2,25,0x0624
lmx2592wr 2,24,0x071A
lmx2592wr 2,23,0x007C
lmx2592wr 2,22,0x0001
lmx2592wr 2,21,0x0401
lmx2592wr 2,20,0xE048
lmx2592wr 2,19,0x27B7
lmx2592wr 2,18,0x0064
lmx2592wr 2,17,0x0146
lmx2592wr 2,16,0x0080
lmx2592wr 2,15,0x064F
lmx2592wr 2,14,0x1E70
lmx2592wr 2,13,0x4000
lmx2592wr 2,12,0x5002
lmx2592wr 2,11,0x0018
lmx2592wr 2,10,0x10D8
lmx2592wr 2,9,0x0604
lmx2592wr 2,8,0x2000
lmx2592wr 2,7,0x40B2
lmx2592wr 2,6,0xC802
lmx2592wr 2,5,0x00C8
lmx2592wr 2,4,0x0A43
lmx2592wr 2,3,0x0642
lmx2592wr 2,2,0x0500
lmx2592wr 2,1,0x0809
lmx2592wr 2,0,0x251C

  • 0 in reply to user5959213
    TI__Guru** 110060 points

    Hi There,

    Can you try:

    (1) after programming and PLL locked, write R2[10] = 0

    or

    (2) set R46[1:0] = 0x2 (set OUTB_MUX = SysRef)

  • 0 in reply to Noel Fung
    Intellectual 865 points

    Hi Noel,

      I have tried as you say above,they don't work.But there is good news when i set R46[1:0]=0x1 (OUTB_MUX=VCO),the half frequency output is improved.

    So the question is, why does the setting here affect the output? And there is any other problem  with my configuration?

    Thanks.

  • 0 in reply to user5959213
    TI__Guru** 110060 points

    Hi There,

    In your register setting, you already have R46[1:0] set to 0x1(lmx2592wr 2,46,0x07FD), this is the recommended setting as it matches with RFoutA.

    if you put this register to 0x0 (Channel Divider), then it is not surprise that you got 1/2 of VCO frequency signal, as the divider is not shut down although you have power down RFoutB buffer.