Ancestors

Written by Cosmic Meow Background on 2025-01-22 at 14:48

🥔 active emi filters

i just think they're neat

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Written by Cosmic Meow Background on 2025-01-22 at 14:49

posts will get more deranged the longer i have to stare into all those friggin datasheets

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Written by Cosmic Meow Background on 2025-01-22 at 14:50

procrastinating assembling the BMS by procrastinating a DC/DC by doing another DC/DC.

damn my workdays are quite... monotone these days (i'll see myself out, sorry to anyone who gets that joke)

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Written by Cosmic Meow Background on 2025-01-22 at 15:31

elen in the jlc part search, when Results remaining: 0

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Written by Cosmic Meow Background on 2025-01-22 at 15:31

i should touch some grass

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Toot

Written by Cosmic Meow Background on 2025-01-22 at 15:36

i lied, i don't have grass at home, come join me on my descent into madness drawing this compensation network

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Descendants

Written by Cosmic Meow Background on 2025-01-22 at 16:03

alright alright alright, i think i got it: https://www.infineon.com/dgdl/Infineon-BSC072N08NS5-DataSheet-v02_01-EN.pdf?fileId=5546d4624ad04ef9014ae3d8e8192c7c

this is the FET. it's available, it's <1 USD for JLC assembly and i'm out of ideas where i could find something better. Qg could be lower but Rdson is pretty much the lowest i could find with those specs.

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Written by Graham Sutherland / Polynomial on 2025-01-22 at 16:05

@cmb this sounds like a fun design! what's the rough spec?

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Written by Cosmic Meow Background on 2025-01-22 at 16:10

@gsuberland just doing a revision of the wide Vin point-of-load board for 48V home bus.

i'm going with the LM5148 for this revision, but i'm designing around the LM5149 too and just dnp-ing the active emi filter stuff, i'll switch out one or two to get tested maybe sometime.

uhh, design constraints are just that i got lost in squeezing out the last bit of efficiency because... reasons.

that and goal is to be able to just order it from JLC whenever i need some more PoLs to switch all the wallwarts at home to the dc bus.

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Written by Graham Sutherland / Polynomial on 2025-01-22 at 16:47

@cmb nice!

if you want to save a bit of money, maybe take a look at the BSZ075N08NS5 as an alternative, which is £0.63/pc instead of £0.97/pc.

the Rds(on) maximum is about 4% higher, but if you look at the detailed spec it's 6.4mΩ typ @ Vgs=10V for both. the Qg is identical but the BSZ075 has a lower Miller plateau voltage so its switching times are improved by about 40% versus the BSC072, so in a switching application they'll probably be roughly identical.

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Written by Cosmic Meow Background on 2025-01-22 at 16:51

@gsuberland oh thanks, that's perfect! there's even more of it in stock too

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Written by Graham Sutherland / Polynomial on 2025-01-22 at 16:51

@cmb the BSC072 does have slightly better thermals (50K/W for 6cm^2 board area versus 60K/W on the BSZ075) but that's mostly just because it's a physically larger package, so you get a larger thermal transfer area from the drain pad.

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Written by Cosmic Meow Background on 2025-01-22 at 16:57

@gsuberland yeah, i like the smol package of the BSZ better anyways and it's ideally not going to be an issue thermally, if it is I did something wrong :D

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