• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 22 subscribers
  • Views 233 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMX2592: questions to confirm the device can meet their requirements

Noriyuki Takahashi
Genius 12220 points

Part Number: LMX2592

Hi team,

There are three questions. Could you support this?

1. We can see fOUT = 606.25 MHz on the figure 23 of the datasheet. Are there any information of the 2nd, 3rd, 4th and 5th harmonic distortion for fOUT?
If you don't have any data, are there any ways to estimate the distortion?

2. On the figure 23, we can see the divider, 1/8. Is it possible to change the number of denominator, 8 to other number? Especially, they want to change it to not integer, but decimal like 1.2 and so on. Is this possible?

3. From what frequency the VCO doubler start to be activated?

4. Their output range is 3GHz~9GHz. And they want to make the harmonic level -40~-50dBc. Do you think it's possible to achieve the distortion level?
They guess the distortion level of the fundamental frequency for the doubler can be high. 

5. If LMX2592 can't meet their requirement( output range is 3GHz~9GHz,  the harmonic level -40~-50dBc), are there any recommendation else?

Regards,

Noriyuki Takahashi

  • +1
    TI__Guru** 121240 points

    Hi Takahashi-san,

    1. We don't have the harmonic data at this frequency. Since it is a divided down frequency, I expect the 3rd and 5th harmonic will be high. I guess it would be -10dBc and -15dBc respectively. 

    2. The 1/8 is the output divider, which is an integer divider and therefore cannot be a fraction. 

    3. You can enable the VCO doubler at any valid VCO frequency.

    4&5. The 2nd and 3rd harmonic of a 3GHz signal is 6GHz and 9GHz, those are within the required frequency range of 3G - 9GHz. So unless they implement a tracking filter, it is not possible to achieve this level of harmonic reduction.