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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: MOSFET Analog Switch Question Date: Sun, 20 Apr 2025 21:51:27 +1000 Organization: A noiseless patient Spider Lines: 25 Message-ID: References: <877c3fyj1k.fsf@librehacker.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sun, 20 Apr 2025 13:51:30 +0200 (CEST) Injection-Info: dont-email.me; posting-host="a01f12bb441905d8f29ce074a18b3533"; logging-data="3925268"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+eH51CtMRrZZkA/q2WeWhWR6BuVr+QuKM=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:pQG9aQWK534+3Ous/7V4AlXCtQc= In-Reply-To: X-Antivirus: Norton (VPS 250420-2, 20/4/2025), Outbound message X-Antivirus-Status: Clean Content-Language: en-US Bytes: 2191 On 20/04/2025 2:46 pm, john larkin wrote: > On Sat, 19 Apr 2025 12:48:23 -0800, Christopher Howard > wrote: > >> Hi, I have some DG212BDJ Quad SPST CMOS Analog Switches. I am wondering >> if there is some significance, for each switch, to how the source and >> drain pins are used/fed. The data sheet says Analog Signal Range >> (V_Analog) is +/- 15 V, so it doesn't matter which way the current is >> moving across source and drain pins, right? > > It should be symmetric, happy conducting in either direction. Only in the sense of conducting both ways. N-MOSFets tend to be more conductive than P-MOSFets. If they make the P-MOSFets bigger than the N-MOSFets they can can balance the channel resistances, but not the channel capacitances. > Don't let the signals go beyond the rails. That would reverse bias the isolation diodes and feed current into the rails, and elsewhere if you are unlucky. The effects can be unfortunate. -- Bill Sloman, Sydney