LM25118-Q1: Boost mode phase waveform

Che Wen Yeh

Part Number: LM25118-Q1
Other Parts Discussed in Thread: LM25118

Tool/software:

Hi,

In Boost mode(Vin 9V, Vout 24V, Iout 0.9A), We measure phase node waveform as following.

Vmax 29.5V, Vmin -4.9V, Jitter 125nS, Is this within the normal range for the LM251180-Q1, or are there any adjustments needed for schematic? Thanks.

0 Hassan Jamal 6 months ago

Hi Che,

Thanks for using E2E forum.

You will get a response from us next week.

Best Regards,

Hassan

+1 Stefan Schauer 5 months ago in reply to Hassan Jamal

Hi Che,

the jitter is a little bit high and might come from a not optimized routing of the sense resistor to the LM25118.

Note: this should be done as a Kelvin connection to avoid disturbance to be coupled in, esp. through CSG line.

Also the undershoot of -4.9V is violating the abs max spec of the HS node.

Double check your measurement setup if this is due to wrong probing see also:

Tip & Barrel:

Slide 28

Best regards,

Stefan

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