• HMC440 ref duty cycle

    I am working on a 1GHz reference clock source with HMC440 PLL. I am planning to use a square wave 100MHz reference signal (0-5dBm). Does the duty cycle have to be strictly 50%?

  • A question about HMC440 Loop Filter

    Dear all,

    I've been working on a HMC440 PLL with Wenzel 100MHz OCXO as reference, and a very narrow band (Ko = 120kHz/V) VCO runs at 1GHz.

    The "Hittite Microwave PLL Design & Analysis Tool Version 1.1" shows the output phase noise is dominated by…

  • some questions about the simulation of HMC440  


     when i use HITTITE PLL DESIGN (v1.1) to simulate the loop filter of HMC440. i  find some questions.

    Firstly, i simulate the loop filter of HMC440 in its datasheet . The schematic  just like below.

    but the 3dB bandwidth of the simulation does…

  • HMC738 and HMC440 available in DIE form?

    I would like to know if the HMC738 VCO and HMC440 PLL can be made available in DIE. Also if it possible to have these devices screened for Tjc max of 150 degC?

  • HMC440 Evaluation Board - defect or am I doing something wrong?


    I am currently working on a project using the HMC440 Evaluation Board. I started working with the board on Monday and it did seem to work then. When I attempted to do some more tests with it on Tuesday I couldn't get it to work at all. The only…

  • RE: HMC394LP4E datasheet


    The datasheet for HMC394 on the website is suspect and has some errors as you mentioned. We are going to update it asap. For now, I recommend you to reference to HMC440 datasheet, which actually is HMC394 incorporating a digital PFD. Their specifications…

  • RE: Getting a voltage proportional to phase from a charge pump.

    Hi David,

    I've no idea of your application, but have you looked at the Hittite (now ADI) HMC440?

  • RE: HMC3716 PFD in adiSimPLL

    Hi there,

    Please reference the EZ post below. The documents referred apply to all HMC PFD / INT PLL products including the HMC439, HMC440, HMC3716, HMC4069, HMC698 and HMC699.


    Best Regards,


  • RE: What is the phase noise of HMC439 at 10Hz offset for 10 MHz pdf?

    Hi David,

    Thank you for information.

    HMC3716 seems to be a good alternative to reduce circuit size. Is there any alternative to HMC440 including LD and INV functions and having similar phase noise performance?

    Best regards,


  • RE: Single tone signal generation at microwave frequency with best phase noise and spurious performance

    Thanks @viktor_vojta. Yes PLL is very good. But by the best PFDs with the best phase noise floor, as I know, such as HMC440 with about -150dBc/Hz phase noise floor for 100MHz input, the PLL output signal at near offsets in the loop bandwidth is limited…