Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: john larkin Newsgroups: sci.electronics.design Subject: Re: neat Hall sensor Date: Fri, 03 Jan 2025 08:07:49 -0800 Organization: A noiseless patient Spider Lines: 73 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Injection-Date: Fri, 03 Jan 2025 17:07:52 +0100 (CET) Injection-Info: dont-email.me; posting-host="29fc9ee0f58f512cfafc48402205d147"; logging-data="4182257"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/bj4V8h7lDnNs2RrGu3418" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:NKo44gIZ2s+iCaX3TpeMSauFv7w= Bytes: 3446 On Fri, 03 Jan 2025 09:33:01 -0500, legg wrote: >On Thu, 02 Jan 2025 08:09:16 -0800, john larkin wrote: > >>On Thu, 02 Jan 2025 09:05:03 -0500, legg wrote: >> >>>On Tue, 31 Dec 2024 15:58:07 -0800, john larkin >>>wrote: >>> >>>> >>>>https://www.monolithicpower.com/en/mcs1802.html?srsltid=AfmBOoq2BNuYQ-Ef5ee9o7-gyHDqRkK_xS5TAKb-MgxtjZ6r71FItxXm >>>> >>>>Really nice, as compared to a shunt and an isolated ADC and all that >>>>stuff. Reasonably accurate, especially above 20c. >>>> >>>>But they can't be serious about pushing 50 amps through an SO8 >>>>package. Or not for long. >>>> >>>>Their demo board thermal design is kinda silly. >>>> >>>> >>> >>>Demo board makes sense to me. Simplest thermal conductivity >>>test. >> >>They used 4 oz copper, hardly practical. > >? > >What's impractical about 4oz copper in a power circuit? >Are you saying it's not enough? I'm saying that you can't put any other reasonable parts on the board. 4 Oz is fine for a demo board, but not so good for a board with 0402 parts and FPGAs and anything that does anything but measure current. It would be interesting to get the eval board and actually push 50 amps through it. I see a lot of data sheets with absurd power and current ratings, like a dpak rated for hundreds of amps and watts, with tiny footnote somewhere that cautions about package or lead limits. IR started the trend of specifying chip therortetical limits that can't be approached in real life, and then everybody had to tag along. > >I'd say it was more than could be expected from a >simple demo board and is typical of higher current >layout in this neck of the woods, where power and >control circuits try not to share the same board or >board layer. Exactly. > >Also, using a part with a 50A full scale in a 25-30A >continuous rated circuit would be normal pactice, >where duty cycle, crest factor or pulse/surge are >anticipated under normal operating conditions. > >There are 'better' SMD packages available, if that is your >only concern. You seem to have found some. They could at least merged the high current pin pairs into big paddles. It's a nice part. We're using the 10 amp version at up to 7.5 amps. The 50 amp version is silly. > >RL