• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 21 subscribers
  • Views 578 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.

LMX2594: Suitable MASH_ORDER

Nobuhiko Wasa
Intellectual 1050 points
Part Number: LMX2594

Hi team,

My customer is asking us about suitable MASH_ORDER selection. According to TICS Pro, in case of Fosc = 200MHz and Fvco = 11.3GHz, N = 56 and fraction = 1/2, then MASH_ORDER should be other than interger mode. If we look at the Table 2 in the datasheet, MASH_ORDER = 1 ~ 4 seems to be OK. How can the customer select the best MASH_ORDER option with considering spurious performance? What is the relation between MASH_ORDER and spurious?

Thanks,
Nobuhiko Wasa

  • 0
    TI__Guru** 107030 points

    Hi Nobuhiko,

    I suggest use 3rd order for both integer and fractional channels, this way you don't have to worry about changing MASH order for every frequency channel you are working on.

    Please note, the N-divider has a min. value restriction and this is MASH order dependent, see datasheet Table 2 for details. N-divider is the key factor that will affect your choice of MASH order.

    The order of MASH is proportional to the number of discrete N value that are used to implement fraction. Please watch a small video for the theory of MASH order. In general, a higher order MASH returns better spurs. 

  • 0 in reply to Noel Fung
    TI__Intellectual 1050 points

    Hi Noel,

    Thank you for you prompt reply.
    Let me talk with the customer about your suggestion.

    Thanks,
    Nobuhiko Wasa