• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 68 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.

LM70880QEVM: Modifications and evaluations of the LM70880Q EVM

Spencer Waguespack
Prodigy 50 points
Part Number: LM70880QEVM
Other Parts Discussed in Thread: LM70860, LM70880

Tool/software:

Hello,

I am designing a board that will have a bunch of these DCDC converters on board. I will be modifying the EVM of this part to evaluate my configuration of the LM70860Q in a circuit. I have the following questions:

  1. If I am planning to use the LM70860 Do I need to remove the LM70880 that comes on the part or is the LM70880 close enough to the LM70860 that I do not need to change the parts.
  2. I want to capture Bode plots at various input voltages and output loading conditions. The EVM user manual is unclear about how to capture these. I have a scope with a frequency response analyzer Is there a guide on how to run this test with this EVM? 
  • +1
    TI__Guru 56345 points

    Hi Spencer,

    Spencer Waguespack said:
    If I am planning to use the LM70860 Do I need to remove the LM70880 that comes on the part or is the LM70880 close enough to the LM70860 that I do not need to change the parts.

    I think the part is close enough that you do not need to change the ICs.

    Spencer Waguespack said:
    I want to capture Bode plots at various input voltages and output loading conditions. The EVM user manual is unclear about how to capture these. I have a scope with a frequency response analyzer Is there a guide on how to run this test with this EVM? 

    The LM70880-Q1EVM is not setup to run bode plots because the IC is setup for a fixed output voltage option. You would need to modify the EVM. See below:

    To measure a bode plot, you will need to inject an AC signal by "breaking the loop". See link below for more details on how to measure a bode plot.

    https://www.tij.co.jp/jp/lit/an/sluaa51/sluaa51.pdf

    Ben

  • 0 in reply to Ben C
    TI__Guru 56345 points

    Hi Spencer,

    Are there any updates? Any additional questions? If not, please close the thread by clicking on "resolved". Thanks!

    Ben