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ADF4158+BGT24MTR11 Frequency lock

I am developing a CW radar using the ADF4158+BGT24MTR11, the BGT24MTR11 is currently working and I am ready to set the lock frequency to 23.5GHZ(This frequency is divided by 16 and then input to the ADF4158),However, when I wrote the configuration information of the ADF4158, the modulation voltage output reached 3.2V, which was far beyond the VCO range of the BGT24MTR11。

REF_IN:10MHZ
Configuration information:
unsigned char R0[] = { 0x00, 0x24, 0xB8, 0x00}; // 23.50001 GHz
unsigned char R1[] = {0x02, 0x26, 0x00, 0x01}; // 23.50001 GHz
unsigned char R2[] = { 0x02, 0x00, 0xFD, 0x02};
unsigned char R3[] = { 0x00, 0x00, 0x00, 0x43};
unsigned char R4[] = { 0x00, 0x18, 0xF4, 0x04};
unsigned char R5_load1[] = { 0x00, 0x49, 0x40, 0x05};
unsigned char R5_load2[] = { 0x00, 0x80, 0x00, 0x7D};
unsigned char R6_load1[] = { 0x00, 0x00, 0x00, 0x56};
unsigned char R6_load2[] = { 0x00, 0x80, 0x00, 0x06};
unsigned char R7[] = { 0x00, 0x02, 0xFD, 0x07};
void ADF4158_config(void)
{

WriteToADF4158(R7);
WriteToADF4158(R6_load1);
WriteToADF4158(R6_load2);
WriteToADF4158(R5_load1);
WriteToADF4158(R5_load2);
WriteToADF4158(R4);
WriteToADF4158(R3);
WriteToADF4158(R2);
WriteToADF4158(R1);
WriteToADF4158(R0); //last one to be loaded (double-buffered).
}


23.5GHZ corresponding voltage range:

Top Replies

    •  Analog Employees 
    •  Super User 
    Aug 3, 2023 in reply to flyman +1 verified

    Hi ,

    I investigated BGT24MTR11 and found that this chip has two different Vtune structures. Did you set the COARSE Vtune value to achieve 23.5 GHz? Can you debug the system by using the following method…

Parents Reply
  • The configuration is as follows:
    unsigned char R0[] = { 0x00, 0x24, 0xB8, 0x00}; // 23.50001 GHz
    unsigned char R1[] = {0x02, 0x26, 0x00, 0x01}; // 23.50001 GHz
    unsigned char R2[] = { 0x02, 0x20, 0xFD, 0x02};
    unsigned char R3[] = { 0x00, 0x00, 0x00, 0x43};
    unsigned char R4[] = { 0x00, 0x18, 0xF4, 0x04};
    unsigned char R5_load1[] = { 0x00, 0x49, 0x40, 0x05};
    unsigned char R5_load2[] = { 0x00, 0x80, 0x00, 0x7D};
    unsigned char R6_load1[] = { 0x00, 0x00, 0x00, 0x56};
    unsigned char R6_load2[] = { 0x00, 0x80, 0x00, 0x06};
    unsigned char R7[] = { 0x00, 0x02, 0xFD, 0x07};

    The modulation voltage has not changed

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