LMX2820: 18.5GHz frequency is out of lock

Part Number: LMX2820

Tool/software:

Hi Noel,
 I hv used LMX2820 for 18.5GHz frequency generation, I am observing 18.5GHz is going out of lock over the period .

Among 50ICs assembled 23 ICs are having this issue Plz suggest some solution Here I am attaching Registers  value here


 uint8_t R122[3]={0x7A,0x00,0x00};
uint8_t R121[3]={0x79,0x00,0x00};
uint8_t R120[3]={0x78,0x00,0x00};
uint8_t R119[3]={0x77,0x00,0x00};
uint8_t R118[3]={0x76,0x00,0x00};
uint8_t R117[3]={0x75,0x00,0x00};
uint8_t R116[3]={0x74,0x00,0x00};
uint8_t R115[3]={0x73,0x00,0x00};
uint8_t R114[3]={0x72,0x00,0x00};
uint8_t R113[3]={0x71,0x00,0x00};
uint8_t R112[3]={0x70,0xFF,0xFF};
uint8_t R111[3]={0x6F,0x00,0x00};
uint8_t R110[3]={0x6E,0x00,0x1F};
uint8_t R109[3]={0x6D,0x00,0x00};
uint8_t R108[3]={0x6C,0x00,0x00};
uint8_t R107[3]={0x6B,0x00,0x00};
uint8_t R106[3]={0x6A,0x00,0x00};
uint8_t R105[3]={0x69,0x00,0x0A};
uint8_t R104[3]={0x68,0x00,0x14};
uint8_t R103[3]={0x67,0x00,0x14};
uint8_t R102[3]={0x66,0x00,0x28};
uint8_t R101[3]={0x65,0x03,0xE8};
uint8_t R100[3]={0x64,0x05,0x33};
uint8_t R99[3]={0x63,0x19,0xB9};
uint8_t R98[3]={0x62,0x1C,0x80};
uint8_t R97[3]={0x61,0x00,0x00};
uint8_t R96[3]={0x60,0x17,0xF8};
uint8_t R95[3]={0x5F,0x00,0x00};
uint8_t R94[3]={0x5E,0x00,0x00};
uint8_t R93[3]={0x5D,0x10,0x00};
uint8_t R92[3]={0x5C,0x00,0x00};
uint8_t R91[3]={0x5B,0x00,0x00};
uint8_t R90[3]={0x5A,0x00,0x00};
uint8_t R89[3]={0x59,0x00,0x00};
uint8_t R88[3]={0x58,0x03,0xFF};
uint8_t R87[3]={0x57,0xFF,0x00};
uint8_t R86[3]={0x56,0x00,0x40};
uint8_t R85[3]={0x55,0x00,0x00};
uint8_t R84[3]={0x54,0x00,0x40};
uint8_t R83[3]={0x53,0x0F,0x00};
uint8_t R82[3]={0x52,0x00,0x00};
uint8_t R81[3]={0x51,0x00,0x00};
uint8_t R80[3]={0x50,0x01,0xC0};
uint8_t R79[3]={0x4F,0x01,0x1E};
uint8_t R78[3]={0x4E,0x00,0x02};
uint8_t R77[3]={0x4D,0x07,0x08};
uint8_t R76[3]={0x4C,0x00,0x00};
uint8_t R75[3]={0x4B,0x00,0x00};
uint8_t R74[3]={0x4A,0x00,0x00};
uint8_t R73[3]={0x49,0x00,0x00};
uint8_t R72[3]={0x48,0x00,0x00};
uint8_t R71[3]={0x47,0x00,0x00};
uint8_t R70[3]={0x46,0x00,0x0E};
uint8_t R69[3]={0x45,0x00,0x11};
uint8_t R68[3]={0x44,0x00,0x20};
uint8_t R67[3]={0x43,0x10,0x00};
uint8_t R66[3]={0x42,0x00,0x3F};
uint8_t R65[3]={0x41,0x00,0x00};
uint8_t R64[3]={0x40,0x40,0x80};
uint8_t R63[3]={0x3F,0xC3,0x50};
uint8_t R62[3]={0x3E,0x00,0x00};
uint8_t R61[3]={0x3D,0x03,0xE8};
uint8_t R60[3]={0x3C,0x01,0xF4};
uint8_t R59[3]={0x3B,0x13,0x88};
uint8_t R58[3]={0x3A,0x00,0x00};
uint8_t R57[3]={0x39,0x00,0x01};
uint8_t R56[3]={0x38,0x00,0x01};
uint8_t R55[3]={0x37,0x00,0x02};
uint8_t R54[3]={0x36,0x00,0x00};
uint8_t R53[3]={0x35,0x00,0x00};
uint8_t R52[3]={0x34,0x00,0x00};
uint8_t R51[3]={0x33,0x20,0x3F};
uint8_t R50[3]={0x32,0x00,0x80};
uint8_t R49[3]={0x31,0x00,0x00};
uint8_t R48[3]={0x30,0x41,0x80};
uint8_t R47[3]={0x2F,0x03,0x00};
uint8_t R46[3]={0x2E,0x03,0x00};
uint8_t R45[3]={0x2D,0x66,0x66};
uint8_t R44[3]={0x2C,0x66,0x66};
uint8_t R43[3]={0x2B,0x00,0x01};
uint8_t R42[3]={0x2A,0x00,0x00};
uint8_t R41[3]={0x29,0x00,0x00};
uint8_t R40[3]={0x28,0x00,0x00};
uint8_t R39[3]={0x27,0x00,0x04};
uint8_t R38[3]={0x26,0x00,0x00};
uint8_t R37[3]={0x25,0x03,0x00};
uint8_t R36[3]={0x24,0x00,0x2E};
uint8_t R35[3]={0x23,0x31,0x00};
uint8_t R34[3]={0x22,0x00,0x10};
uint8_t R33[3]={0x21,0x00,0x00};
uint8_t R32[3]={0x20,0x10,0x81};
uint8_t R31[3]={0x1F,0x04,0x01};
uint8_t R30[3]={0x1E,0xB1,0x8C};
uint8_t R29[3]={0x1D,0x31,0x8C};
uint8_t R28[3]={0x1C,0x06,0x39};
uint8_t R27[3]={0x1B,0x80,0x01};
uint8_t R26[3]={0x1A,0x0D,0xB0};
uint8_t R25[3]={0x19,0x06,0x24};
uint8_t R24[3]={0x18,0x0E,0x34};
uint8_t R23[3]={0x17,0x11,0x02};
uint8_t R22[3]={0x16,0xE2,0xBF};
uint8_t R21[3]={0x15,0x1C,0x64};
uint8_t R20[3]={0x14,0x27,0x2C};
uint8_t R19[3]={0x13,0x21,0x20};
uint8_t R18[3]={0x12,0x00,0x00};
uint8_t R17[3]={0x11,0x15,0xC0};
uint8_t R16[3]={0x10,0x17,0x1C};
uint8_t R15[3]={0x0F,0x20,0x01};
uint8_t R14[3]={0x0E,0x30,0x01};
uint8_t R13[3]={0x0D,0x00,0x38};
uint8_t R12[3]={0x0C,0x04,0x08};
uint8_t R11[3]={0x0B,0x06,0x12};
uint8_t R10[3]={0x0A,0x10,0x00};
uint8_t R9[3]={0x09,0x00,0x05};
uint8_t R8[3]={0x08,0xC8,0x02};
uint8_t R7[3]={0x07,0x00,0x00};
uint8_t R6[3]={0x06,0x0A,0x43};
uint8_t R5[3]={0x05,0x00,0x32};
uint8_t R4[3]={0x04,0x42,0x04};
uint8_t R3[3]={0x03,0x00,0x41};
uint8_t R2[3]={0x02,0x81,0xF4};
uint8_t R1[3]={0x01,0x57,0xA0};
uint8_t R0[3]={0x00,0x64,0x70};
                                      

  • Hi there,

    what is your reference clock frequency?

  • 100MHz is the reference frequency

  • uint8_t R122[3]={0x7A,0x00,0x00};
    uint8_t R121[3]={0x79,0x00,0x00};
    uint8_t R120[3]={0x78,0x00,0x00};
    uint8_t R119[3]={0x77,0x00,0x00};
    uint8_t R118[3]={0x76,0x00,0x00};
    uint8_t R117[3]={0x75,0x00,0x00};
    uint8_t R116[3]={0x74,0x00,0x00};
    uint8_t R115[3]={0x73,0x00,0x00};
    uint8_t R114[3]={0x72,0x00,0x00};
    uint8_t R113[3]={0x71,0x00,0x00};
    uint8_t R112[3]={0x70,0xFF,0xFF};
    uint8_t R111[3]={0x6F,0x00,0x00};
    uint8_t R110[3]={0x6E,0x00,0x1F};
    uint8_t R109[3]={0x6D,0x00,0x00};
    uint8_t R108[3]={0x6C,0x00,0x00};
    uint8_t R107[3]={0x6B,0x00,0x00};
    uint8_t R106[3]={0x6A,0x00,0x00};
    uint8_t R105[3]={0x69,0x00,0x0A};
    uint8_t R104[3]={0x68,0x00,0x14};
    uint8_t R103[3]={0x67,0x00,0x14};
    uint8_t R102[3]={0x66,0x00,0x28};
    uint8_t R101[3]={0x65,0x03,0xE8};
    uint8_t R100[3]={0x64,0x05,0x33};
    uint8_t R99[3]={0x63,0x19,0xB9};
    uint8_t R98[3]={0x62,0x1C,0x80};
    uint8_t R97[3]={0x61,0x00,0x00};
    uint8_t R96[3]={0x60,0x17,0xF8};
    uint8_t R95[3]={0x5F,0x00,0x00};
    uint8_t R94[3]={0x5E,0x00,0x00};
    uint8_t R93[3]={0x5D,0x10,0x00};
    uint8_t R92[3]={0x5C,0x00,0x00};
    uint8_t R91[3]={0x5B,0x00,0x00};
    uint8_t R90[3]={0x5A,0x00,0x00};
    uint8_t R89[3]={0x59,0x00,0x00};
    uint8_t R88[3]={0x58,0x03,0xFF};
    uint8_t R87[3]={0x57,0xFF,0x00};
    uint8_t R86[3]={0x56,0x00,0x40};
    uint8_t R85[3]={0x55,0x00,0x00};
    uint8_t R84[3]={0x54,0x00,0x40};
    uint8_t R83[3]={0x53,0x0F,0x00};
    uint8_t R82[3]={0x52,0x00,0x00};
    uint8_t R81[3]={0x51,0x00,0x00};
    uint8_t R80[3]={0x50,0x01,0xC0};
    uint8_t R79[3]={0x4F,0x01,0x1E};
    uint8_t R78[3]={0x4E,0x00,0x02};
    uint8_t R77[3]={0x4D,0x07,0x08};
    uint8_t R76[3]={0x4C,0x00,0x00};
    uint8_t R75[3]={0x4B,0x00,0x00};
    uint8_t R74[3]={0x4A,0x00,0x00};
    uint8_t R73[3]={0x49,0x00,0x00};
    uint8_t R72[3]={0x48,0x00,0x00};
    uint8_t R71[3]={0x47,0x00,0x00};
    uint8_t R70[3]={0x46,0x00,0x0E};
    uint8_t R69[3]={0x45,0x00,0x11};
    uint8_t R68[3]={0x44,0x00,0x20};
    uint8_t R67[3]={0x43,0x10,0x00};
    uint8_t R66[3]={0x42,0x00,0x3F};
    uint8_t R65[3]={0x41,0x00,0x00};
    uint8_t R64[3]={0x40,0x40,0x80};
    uint8_t R63[3]={0x3F,0xC3,0x50};
    uint8_t R62[3]={0x3E,0x00,0x00};
    uint8_t R61[3]={0x3D,0x03,0xE8};
    uint8_t R60[3]={0x3C,0x01,0xF4};
    uint8_t R59[3]={0x3B,0x13,0x88};
    uint8_t R58[3]={0x3A,0x00,0x00};
    uint8_t R57[3]={0x39,0x00,0x01};
    uint8_t R56[3]={0x38,0x00,0x01};
    uint8_t R55[3]={0x37,0x00,0x02};
    uint8_t R54[3]={0x36,0x00,0x00};
    uint8_t R53[3]={0x35,0x00,0x00};
    uint8_t R52[3]={0x34,0x00,0x00};
    uint8_t R51[3]={0x33,0x20,0x3F};
    uint8_t R50[3]={0x32,0x00,0x80};
    uint8_t R49[3]={0x31,0x00,0x00};
    uint8_t R48[3]={0x30,0x41,0x80};
    uint8_t R47[3]={0x2F,0x03,0x00};
    uint8_t R46[3]={0x2E,0x03,0x00};
    uint8_t R45[3]={0x2D,0x00,0x00};
    uint8_t R44[3]={0x2C,0x40,0x00};
    uint8_t R43[3]={0x2B,0x00,0xFA};
    uint8_t R42[3]={0x2A,0x00,0x00};
    uint8_t R41[3]={0x29,0x00,0x00};
    uint8_t R40[3]={0x28,0x00,0x00};
    uint8_t R39[3]={0x27,0x03,0xE8};
    uint8_t R38[3]={0x26,0x00,0x00};
    uint8_t R37[3]={0x25,0x05,0x00};
    uint8_t R36[3]={0x24,0x00,0x2E};
    uint8_t R35[3]={0x23,0x31,0x00};
    uint8_t R34[3]={0x22,0x00,0x10};
    uint8_t R33[3]={0x21,0x00,0x00};
    uint8_t R32[3]={0x20,0x10,0x01};
    uint8_t R31[3]={0x1F,0x04,0x01};
    uint8_t R30[3]={0x1E,0xB1,0x8C};
    uint8_t R29[3]={0x1D,0x31,0x8C};
    uint8_t R28[3]={0x1C,0x06,0x39};
    uint8_t R27[3]={0x1B,0x80,0x01};
    uint8_t R26[3]={0x1A,0x0D,0xB0};
    uint8_t R25[3]={0x19,0x06,0x24};
    uint8_t R24[3]={0x18,0x0E,0x34};
    uint8_t R23[3]={0x17,0x11,0x02};
    uint8_t R22[3]={0x16,0xE2,0xBF};
    uint8_t R21[3]={0x15,0x1C,0x64};
    uint8_t R20[3]={0x14,0x27,0x2C};
    uint8_t R19[3]={0x13,0x21,0x20};
    uint8_t R18[3]={0x12,0x00,0x00};
    uint8_t R17[3]={0x11,0x15,0xC0};
    uint8_t R16[3]={0x10,0x17,0x1C};
    uint8_t R15[3]={0x0F,0x20,0x01};
    uint8_t R14[3]={0x0E,0x30,0x01};
    uint8_t R13[3]={0x0D,0x00,0x38};
    uint8_t R12[3]={0x0C,0x04,0x08};
    uint8_t R11[3]={0x0B,0x06,0x12};
    uint8_t R10[3]={0x0A,0x00,0x00};
    uint8_t R9[3]={0x09,0x00,0x05};
    uint8_t R8[3]={0x08,0xC8,0x02};
    uint8_t R7[3]={0x07,0x00,0x00};
    uint8_t R6[3]={0x06,0x0A,0x43};
    uint8_t R5[3]={0x05,0x00,0x32};
    uint8_t R4[3]={0x04,0x42,0x04};
    uint8_t R3[3]={0x03,0x00,0x41};
    uint8_t R2[3]={0x02,0x81,0xF4};
    uint8_t R1[3]={0x01,0x57,0xA0};
    uint8_t R0[3]={0x00,0x64,0x70};

    I have updated these registers still I am getting signal out of lock (noisy ) plz suggest

  • Hi There, 

    Your configuration is fine, however, you have the output muted if the MUTE pin is LOW, because PINMUTE_POL is set to Active LOW. If you have the MUTE pin connected to Ground, set PINMUTE_POL to 0, you should see signal coming output from RFOUTA.