<azonenberg>
AKL-PD1 panel received from fab, waiting for it to ship
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<d1b2>
<Hardkrash> @azonenberg The USB-C cables you linked at 2m length had DCR of 1.2Ω to 1.5Ω for all 8 SS conductors. Tested at 100mA load, includes the test boards trace resistance which could be resistance difference.
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<azonenberg>
hardkrash: individually 1.2 to 1.5?
<azonenberg>
using the worst case 1.5 ohms we'll call it 375 milliohms for both positive and negative (four lines in parallel), or 750 mR total series resistance in the power loop
<d1b2>
<Hardkrash> yes, each conductor. using 2 pairs 4 conductors for a circuit would yield about 375mΩ
<d1b2>
<Hardkrash> one direction, not loop
<azonenberg>
let's say 250 mA current drawn by a probe (so far this sounds high, the AKL-AD1 prototype doesn't get over 100 mA)
<azonenberg>
Which comes out to 188 mV drop
<d1b2>
<Hardkrash> and this is a cable twice as long as the original specified.
<azonenberg>
And 47 mW of total joule heating in the cable
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<azonenberg>
So i think we have plenty of margin here
<d1b2>
<Hardkrash> so to me, a 200mV drop and the 50mW is very acceptable.
<azonenberg>
Yes i would be inclined to agree
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<d1b2>
<Hardkrash> I also just did a quick calculation, if 32AWG wire for STP conductor, it's ~165mΩ per foot, so about an Ohm for 6 feet. if 34AWG it would be 260mΩ per foot, so about 1.56Ω at 6ft
<d1b2>
<Hardkrash> so theory and measurements are of the same order.
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<azonenberg>
Interesting
<azonenberg>
I probably should have looked at the ADL5565 s-parameters more before designing the first rev of the AKL-AD1
<azonenberg>
What do you folks think of the LMH3401 for the AKL-AD1 v0.2?
<azonenberg>
vs the ADL5565
<azonenberg>
7 GHz -3 dB BW, but it says "usable" bandwidth of 2 GHz which i'm not clear on the meaning of
<azonenberg>
Fixed gain of 16 dB differential
<azonenberg>
BiCMOS process, vs the ADL5565 is SiGe
<azonenberg>
also compatible with the +/- 2.5V target power supply range i'm going for
<azonenberg>
7 GHz small signal bandwidth, 4 GHz large signal bandwidth (2V p-p output, which is a lot)
<azonenberg>
Or LMH5401
<azonenberg>
ooooh ADL5580
<azonenberg>
lain: ^
<azonenberg>
i think i found a better amp
<azonenberg>
explicitly states dc coupling is ok
<azonenberg>
There is a little bit of P-to-N mismatch which i'm not thrilled about. but it's not huge
<azonenberg>
although it does pull a lot of power
<azonenberg>
276 mA @ 5V, 224 mA @ -1.8V
<lain>
:o
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<azonenberg>
New MEAD MMCX input board came in. This one actually fits the connectors without needing any machining, which is nice
<azonenberg>
gonna populate one tonight probably then if all looks good order enough to outfit the rest of my pods
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<_whitenotifier>
[starshipraider] davidlenfesty opened pull request #5: Active probe testing PCB - https://git.io/JtJd4
<d1b2>
<david.lenfesty> Probably gonna order the PCBs sometime this weekend
<d1b2>
<david.lenfesty> (and do a final final check)
<d1b2>
<david.lenfesty> I really shouldn't be working on this too much over the next few weeks (the semester is starting and I have some other commitments to work on), but I do have a decent chunk of the base FUSB302 and PD library done.