All,
Yes... As soon as I posted it, I realized I should just do a web search.
Duh.
Thanks... I've prior done deep dives into picotest & keysight on PI.
Istvan.... thanks for the pdf link.
Main one I got was this, below, which describes one method with a Network
Analyzer that has a LF out.
You xfmr-couple the LF to the VRM out node, with a DC-block cap & with a
R=1 ohm in the return leg to generate a voltage signal from current.
The NA can do the Z measurement directly (taking into account any scaling
for probes).
It describes another more flexible (?) method using an "electronic load"
box that can also vary the dc load if needed for more extensive tests.
https://community.keysight.com/community/keysight-blogs/general-electronics-measurement/blog/2016/10/12/how-can-i-measure-output-impedance-of-a-dc-power-supply
Regards,
agathon
On Mon, Jul 1, 2019 at 11:07 PM Istvan Novak <istvan.novak@xxxxxxxxxxx>
wrote:
Small signal output impedance, assuming linear and time invariant DUT,
can be measured by applying a stimulus across the converter output and
measuring the response at the same points.?? The stimulus and measurement
can be in the frequency domain by using a Vector Network Analyzer or
Frequency Response Analyzer or it can be done in the time domain by
applying a step-current stimulus and measuring the response with an
oscilloscope.?? in this latter case the time-domain response has to be
transformed into the frequency domain to get impedance versus
frequency.?? You can find measured illustrations for both in
http://www.electrical-integrity.com/Paper_download_files/DC18_PAPER_Track11_HowSpatialVariationofVoltage_Miranda_updated__.pdf
<https://docs.google.com/viewer?url=http%3A%2F%2Fwww.electrical-integrity.com%2FPaper_download_files%2FDC18_PAPER_Track11_HowSpatialVariationofVoltage_Miranda_updated__.pdf>
You can find very good accessories for the measurements on the Picotest
website: https://www.picotest.com/
Regards,
Istvan Novak
Samtec
On 7/1/2019 1:53 PM, agathon wrote:
Small-signal Zout measurement...V,I
This is the primary f-domain characterization of a SMPS.
What is the actual lab setup for this?
(I don't need brand/model instrument recommendations, but separately ok).
I assume the answer is something like ...
the feedback pin node has freq.-swept noise coupled into it and output
are measured (with some nominal dc load). No?
Regards and Thanks.
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