Warning: mysqli::__construct(): (HY000/1203): User howardkn already has more than 'max_user_connections' active connections in D:\Inetpub\vhosts\howardknight.net\al.howardknight.net\includes\artfuncs.php on line 21
Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: john larkin Newsgroups: sci.electronics.design Subject: Re: BAW Date: Wed, 22 Jan 2025 08:27:40 -0800 Organization: A noiseless patient Spider Lines: 59 Message-ID: <1072pj1g4lm05dsnoshped7m9r2r4ies2t@4ax.com> References: <1vptojlpiellv6m47bnjtfblv4u1sa9u05@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Wed, 22 Jan 2025 17:27:41 +0100 (CET) Injection-Info: dont-email.me; posting-host="8835fc4cc479ca23cb28c563d96df0ba"; logging-data="1162307"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/KdrFLva1loxcfTIygTDiu" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:VWTVeLbK1kY9K3Nay2PtIFLf5bk= On Wed, 22 Jan 2025 10:36:06 +0100, Jeroen Belleman wrote: >On 1/22/25 09:38, John R Walliker wrote: >> On 22/01/2025 04:30, Bill Sloman wrote: >>> On 22/01/2025 10:52 am, Buzz McCool wrote: >>>> On 1/21/2025 10:56 AM, john larkin wrote: >>>>> >>>>> This has got to crush the XO business. It looks like it's a single >>>>> chip that's encapsulated like any other IC. XOs are complex and need >>>>> hermetic cans. >>> >>> XOs used to use handmounted crystals. There's nothing all that >>> complicated about them, but low volume manufacture tends to be a bit >>> knife and fork. >>> >>>> Looking through this BAW app note >>>> https://www.ti.com/lit/an/snaa362/snaa362.pdf, I couldn't tell BAW >>>> devices would work at high altitude or in a vacuum. I have to ask >>>> because the "acoustic" in the name makes me want to make sure that >>>> some sort of atmosphere isn't needed. >>> >>> As far as I can see these are surface acoustic wave devices. >>> Integrated circuits are pretty well encapsulated. This one probably >>> dumps any heat it generates into the board it is mounted on, which >>> might run a bit warmer in a vacuum, but that would be the only risk I >>> can see. >>> >> >> It does look more like bulk acoustic waves - hence the name!  There >> is no cavity inside, so they should be immune to the effects of >> helium, unlike the  oscillators that use MEMS resonators where it >> appears that helium can diffuse through the silicon to clog up >> the vacuum cavity. >> Phase noise performance looks excellent as is the temperature >> stability. >> John >> > >You can look up the patent: >. > >Apparently the resonator is built up layer by layer, first >the multi-layer Bragg reflector, then the bottom resonator >electrode, the resonator material itself, and finally the >top electrode. The patent does not mention a top reflector, >so such a resonator would need a bit of free space above. > >The patent text is voluntarily vague about the materials >used for the reflector and resonator layers. They mention >lots of examples, without clearly saying what they really >used. I'd expect that most examples don't work. > >Jeroen Belleman The next step might be to have BAWs on uPs or FPGAs or watch circuits or something, super accurate clocks instead of external XOs or bad RC oscillators.