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Replicating/Copying HP/Agilent/Keysight 16065A High Voltage LCR Meter Fixture
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ZGoode:
I'm working on making a copy of the Keysight 16065A for use with my HP LCR meter and some of my existing fixtures and wanted feedback on my choice of suitable components for this project.  The diodes were relatively straightforward, I think I have the correct ones.  Where I would greatly appreciate feedback would be on my choice of capacitors since nothing is listed in the Keysight manual other than the uF values.  I went ahead and chose caps rated for at least 200V, but wasn't sure if the particular type or tolerance I chose is the best option instead of something else.

C1: 5.6µF https://www.digikey.com/en/products/detail/kemet/C4AQJBU4560M1XJ/13563463
C2: 1µF https://www.digikey.com/en/products/detail/kemet/R75PR410050H3J/12144507
C3,4: 0.001µF https://www.digikey.com/en/products/detail/kemet/PHE426MJ4100JR05/13176743

R1,2: 61.9kΩ https://www.digikey.com/en/products/detail/yageo/MFR-25FTE52-61K9/9140331
R3,4: 38.3kΩ https://www.digikey.com/en/products/detail/yageo/MFR50SFTE52-38K3/9151447
R5,6: 20Ω 20W https://www.digikey.com/en/products/detail/yageo/SQP20AJB-20R/9167197

CR1,2,3,6: BZX55B10 https://www.digikey.com/en/products/detail/vishay-general-semiconductor-diodes-division/BZX55B10-TAP/4826033
CR4,5,7,8: UG56G https://www.digikey.com/en/products/detail/taiwan-semiconductor-corporation/UG56G/7367414
CR9,10,11,12,13,14,15,16: 1N4936 https://www.digikey.com/en/products/detail/diodes-incorporated/1N4936-T/21905
Kean:
Have you seen the design by Mike Wyatt?

He has documented the component values and capacitor types used in his design
https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/msg4133314/#msg4133314

Also there is a post with an internal photo of an original 16065A that might help
https://www.eevblog.com/forum/projects/lcr-measurements-at-high-dc-bias-agilent-16065a-dc-bias-fixture-teardown/msg3958007/#msg3958007
ZGoode:
OOOO, thank you!
I was trying to track down pictures of the actual board itself, but was not having any luck on that.  I'm gonna have to check those posts out.
Based on those two posts, looks like I got pretty close to what they did.  I'm gonna give it a go and see how it performs when the parts come in from Digikey
Kean:
Please update us on how it goes.  I have one of the PCBs that Mike designed but I have not yet ordered the parts for it.
mawyatt:
Notes for the OP.

The 5.6uF in the HP design limits the Low Frequency response (our IM3536 goes down to 4Hz) as it's in series with the Force Signal (Hcur), especially important for measuring low Z DUT at lower frequencies as this forms a voltage divider with the DUT and creates a small voltage at the Sense terminal (Hpot) which is more difficult to measure.

In our rendition we included larger film capacitors (lower voltage tho as we don't generally require anything above 100VDC) for general use, and included ability to add back to back high capacitance electrolytics (jumper terminal on PCB for this) for use with low Z DUT devices.

After much use we also added the ability to quickly charge or discharge the DUT with a push botton, this aids when evaluating larger capacitors as they can take a long time to charge to steady state DC bias. This also serves a similar function as the HP interlock, dumping charge into the power resistor for discharging the DUT.

The only issue we've had with our version, which can be directly connected to LCR bench meter with BNC Male to Male adapters and directly connected to standard fixtures (Like SMD Fixtures) without adapters, is that the spacing of the BNCs was slightly off, someone we know well didn't pay attention during PCB layout |O

We couldn't find anywhere the nice lever arm Male BNC used on the bench LCR meter fixtures, so had to resort to BNC Male to Male adapters for the direct LCR meter interface, of course you can use a standard BNC cable and we have some short ones just for this purpose.

Also we included the ability for the external charge discharge switch with an JST connector (now ours has a PCB wire soldered to a component, sloppy but works). We have an updated version of the PCB and were considering ordered PCBs if interested.

Make sure your version has complete electrical shielding (ground) and is mechanically stable, this is why we chose the extruded aluminum case with aluminum end plates (covered with 3D printed plastic for text and feet), see link Kean mentioned.

Edit: The components you've selected look fine for the HP version, good choices :-+

Anyway, good luck with your implementation, we're here to help if need be.

Best,
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