Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 64 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.

LP5910YKA18EVM: LDO measurement environment

Roy Chou1
Genius 14255 points
Part Number: LP5910YKA18EVM
Other Parts Discussed in Thread: THS3120EVM, LM317

Tool/software:

Hi Team,

We would like measure LDO PSRR. For our measurement, we would like to use scope to check.

1. First setup, we used THS3120EVM to generate the DC+AC voltage signal. And remove the Cin of LP5910EVM like training video said. 

For the scope measured results, (CH1 yellow is the input/ CH2 blue is the output, using AC coupling):

200mA Load

300mA Load

You can see there are spikes on input side.

2. Second setup, DC powering by linear regulator LM317

Oscilloscope measured results (CH1 yellow is the input/ CH2 blue is the output, using DC coupling):

100 mA load:

200mA load

And my question is that

1. How to mitigate these spikes?

2. Do we have LDO measurement environment can be referred? I found the below training video, but would like to double check if we have updated setup.

https://www.ti.com/zh-tw/video/4459556475001

3. Our purpose is that input maybe 10kHz AC signal 1Vpk-pk and see may 0.1Vpk-pk 10kHz AC signal. And we can get PSRR = -20dB at 10kHz.

Regards,

Roy