• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 140 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

LDC1041: questions about Filter capacitor tuning

Kazuhiko Hirano
Genius 11613 points
Part Number: LDC1041
Other Parts Discussed in Thread: LDC1000EVM, LDC1101, LDC3114

Hello,

My customer plans to use LDC1041 for their new design.
They designed an L using WeBench, it is supposed to around 1.2uH.
The L is on their target PCB with a C, 1500pF, in parallel.
They connected their target PCW to LDC1000EVM as follows.

They tried to tune the Filter capacitor on the LDC1000EVM so that CFB pin waveform amplitude gets around 1Vpp.
But, they were not able to see significant amplitude at the CFB pin with 20pF to 1000pF filter capacitor range.
What does TI think is wrong?
Does TI think any suggestions to solve the issue about the L and the C on their target PCB, the Filter capacitor on the LDC1000EVM or any register settings?
What setting is recommended for amplitude bits in the LDC Configuration register?

Best regards,

K.Hirano

  • 0
    TI__Mastermind 33250 points

    Kazuiko,
    What does your customer want to measure?
    We are not recommending the LDC1000/1/41/51 for new designs.
    If they wish to measure L & Rp the LDC1101 would be a better choice than the LDC1041.
    If they only need to measure L, then we have several devices that would be better candidates.

    If they are willing to reconsider their device, please take a look at the LDC Selection Guide.

    A summary of the LDC performance and features from the selction guide:

    If they are determined to use the LDC1041, please have them look at the LDC1000EVM Quick-Start Guide as a next step.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Genius 11613 points

    John,

    Let me confirm some more.
    Q1: What is the LDC1101 specifically better than LDC1041?
    Q2: If my customer would like to measure only L, not Rp, they do not need to tune the filter capacitor at all?

    Best regards,

    K.Hirano

  • 0 in reply to Kazuhiko Hirano
    TI__Mastermind 33250 points

    Kazuhiko,

    The LDC1101 does not require a filter capacitor, has fewer pins (10), and supports up to 16 bits of resolution compared to 16 pins, and only 8 bits for the LDC1041.

    The LDC1101 can estimate Rp and L, but does not require a filter capacitor.
    The other devices mentioned in the table in my last reply do not require a filter capacitor, and will estimate L, but not Rp.
    The LDC3114 is our latest device and supports up to 24 bits of resolution.

    Regards,
    John