• RE: LTC6948-2 ,I can read from LTC6948-2,but I cant write in LTC6948-2 register.


    Are you using the LTC6948 eval board, FracNWizard, and DC2026 (USB to SPI board)?  Or are you trying to write to the part using your own software and hardware?  Can you send a plot of your SCLK, SDI and !CS signals, so I can look at the timing?

    To write…

  • LTC6948 non-simultaneous 3.3V and 5V


    Is it mandatory to power up the PLL LTC6948 with 3V3 and 5V at the same time?

    In other words, can we reset one of the supply while the other is still on?



  • Using LTC6948 as a VCO

    Hello. I'd like to use LTC6948 as a common VCO controlling output freq with an external DAC. But to start VCO i have to keep PLL loop closed. Is there any way to start VCO without the loop at all?

    Best regards, Eugene

  • LTC6948-2 unlock

     i use register as follow,but it does not lock , the ref is 40M,pfd is 20M  output frequency is 985M,integer mode , how can slove this problem


  • combining LTC6948 and LTC5562

    (I asked this also to the technical support, my apologies for double asking but I need a fast answer)

    we combine LTC6948 and LTC5562. LTC6948 creates an LO signal of 920MHz and LTC5562 mixes the baseband onto it.
    Now I measured the output level of…

  • LTC6948's SDO Pin


    If the LTC6948 is not used in a multi-drop configuration, the datasheet recommends a high-value resistor of greater than 200 kOhm between the SDO and GND.

    However, since Ioh = -19.5mA (max), I think that there is no problem if the resistance value…

  • LTC6948 ALCEN default value

    I noticed the datasheet Table 16 shows ALCEN defaults to 1.

    However, the register map in table 15 suggests that ALCEN defaults to 0.  

    I assume that Table 16 is correct, and the ALCEN defaults to 1. So table 15 value for address h03 should be fixed to have…

  • Spurious in LTC6948-2 in fractional mode

    I am using LTC6948-2 device to generate 3.2625 GHz and reference signal is 100 MHz. I am seeing spurious in fractional mode as shown in picture.

    I am using this tool for calculating register value.

    This is my schematic for it.

    Can anyone please tell…

  • LTC6948 issue detection using Demo circuit DC590B

    I am using LTC 6948 in one of my design, I have copied the reference design from the EVAL board of (LTC6948IUFD-3) with DEMO circuit (1959A-C).

    It contain an EEPROM (U5 in the schematic), i would like to know how i can program that EEPROM and what initial…

  • LTC6948-4频率锁不住