Products > Test Equipment
Hioki IM3570 LCR & Impedance Analyzer
KungFuJosh:
--- Quote from: mawyatt on September 29, 2024, 06:09:13 pm ---Repeatability was key in the development, we couldn't get good results with low Z SMDs before this custom fixture, even the Standard SMD fixtures weren't very good.
That's really good, $20 for 5 gold plated custom PCBs with shipping!!! Did the PCBs come from JLCPCB (where ours are from)?
Glad you could use the design, wish others would note the advantage of this technique, it's not like it's expensive.
--- End quote ---
My generic SMD fixture is ok, and usually pretty stable, but doesn't fit all SMD stuff. For example, the 10mΩ resistor was too thin, and fell beneath the contacts.
Yes, JLC. I use JLC for most stuff, sometimes WellPCB for more robust stuff or weirder details. $20 was including removing the order number, shipping, ENIG, PayPal fee, etc. For more expensive PCB orders I pay for the better shipping. In this case, better shipping cost as much as the PCBs, so I took the risk. 😉 It was still pretty fast though. Order placed on 9/15 and delivered on 9/27.
Thanks,
Josh
mawyatt:
--- Quote from: KungFuJosh on September 29, 2024, 06:56:37 pm ---My generic SMD fixture is ok, and usually pretty stable, but doesn't fit all SMD stuff. For example, the 10mΩ resistor was too thin, and fell beneath the contacts.
--- End quote ---
If the Standard SMD Fixture is like ours, getting repeatable results for say a 10 miil-Ω 2512 Resistor within 100~200uΩ was extremely difficult. The plunger contact impedance was the culprit, which of course is partially removed by the Split-Kelvin Technique :-+
Of course the Standard Fixture works quite well for higher Z SMD components, where the contact variations have less impact on the overall DUT measurement.
Best
KungFuJosh:
Ha, well, I couldn't even get the low Z stuff on my generic fixture. 😉
mawyatt:
Yes very difficult with the Standard Fixture. The Zero/Short calibration gives a hint at why this is so. If we do a Zero/Short cal and then come back and make a Zero/Short measurement later we don't get anything repeatable around 0.000Ω for the two Standard SMD Fixtures we have/had (one has been converted to accept External DC Bias).
In defense of these Standard SMD Fixtures they were not intended for low Z measurements because the Force and Sense Terminals on the Hi and Low sides make contact at the thin brass bolt at the plunger bottom. This leaves the entire Low and Hi plunger large diameter cores and thin tip impedances un-sensed as well as the DUT contact impedance on each side un-sensed, which creates an overall high built-in uncertainty in low Z measurements, and this shows up in the Zero/Short Cal attempts :o
However, the Split-Klevin Technique SMD Fixture provides a remedy for such and produces excellent low Z results with good repeatability as you've demonstrated :-+
Simply stated this technique works and works quite well for low Z SMD measurements within capable hands ;)
Best
KungFuJosh:
--- Quote from: mawyatt on September 30, 2024, 02:05:29 pm ---However, the Split-Klevin Technique SMD Fixture provides a remedy for such and produces excellent low Z results with good repeatability as you've demonstrated :-+
--- End quote ---
Not only that, it gives better low Z results on a broader frequency range. I've found with other fixtures it's not too hard to get 0.00mΩ Z at 1kHz after short cal, but going higher will shift that (not too much, but still not 0.00). With your 5A fixture it showed 0.00mΩ at 100kHz, which I don't think I've seen with another fixture.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version