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[49.179.142.238]) by smtp.gmail.com with ESMTPSA id b24sm17769pjq.10.2020.12.08.12.49.45 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 08 Dec 2020 12:49:45 -0800 (PST) Received: from james by esk with local (Exim 4.90_1) (envelope-from ) id 1kmjvZ-0008B0-2Q; Wed, 09 Dec 2020 07:49:41 +1100 From: James Cameron To: Microcontroller discussion list - Public. Sender: "piclist-bounces@mit.edu" Date: Tue, 8 Dec 2020 12:49:41 -0800 Subject: Re: [EE] Eliminating external noise through PS Thread-Topic: [EE] Eliminating external noise through PS Thread-Index: AdbNpNVLFvAvXKUWQvWWdqzN6pGB0A== Message-ID: <20201208204941.GE27145@laptop.org> References: <5FCFC00E.8040703@narwani.org> List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: <5FCFC00E.8040703@narwani.org> Reply-To: Microcontroller discussion list - Public. Accept-Language: en-US X-MS-Exchange-Organization-AuthAs: Anonymous X-MS-Exchange-Organization-AuthSource: TS500.efplus4.local X-MS-Has-Attach: X-Auto-Response-Suppress: All X-MS-Exchange-Organization-SenderIdResult: Pass X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: Pass (protection.outlook.com: domain of laptop.org designates 209.85.215.173 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.215.173; helo=mail-pg1-f173.google.com; dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=laptop-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=xSs9A07JUW/+u0EbSUTAYNqxfsUdIg5ZZnSCxVYso74=; b=df180CZK8ys4E4MpUX/2cp/AaeKdX0ARE6X8kdGOetECRGCOFlA5zNCyWktvVq3AMn /WVw7KfCJ/b09bIxUn1J0pTmjjVY3WbBKIJHNTPC1lQnLEY+z8ulU4h0iCdcd+IVHhmT 6MC48FqxkSh9r1OTCtEruYa2L2spTb6G7g6s4/hQqltyh6fYjnrTe0CWyi8Y6rTFM7Cz Iwj3+oIbqkcMbzZYIWCfXZVF0VTxh8OFC2OV1JMQDwLrw/7Rps8dmvChA4LSgPlFTnYv 5DSQWfxDHX0WdiuddfeLtVbrLGNLkdPUSpkK36So9WdWjuweZVbAVkngsDJaaN/g7YGi KjDg== authentication-results: spf=pass (sender IP is 209.85.215.173) smtp.mailfrom=laptop.org; mit.edu; dkim=pass (signature was verified) header.d=laptop-org.20150623.gappssmtp.com; mit.edu; dmarc=bestguesspass action=none header.from=laptop.org; user-agent: Mutt/1.9.4 (2018-02-28) errors-to: piclist-bounces@mit.edu list-id: "Microcontroller discussion list - Public." list-post: x-beenthere: piclist@mit.edu x-mailman-version: 2.1.6 x-received: by 2002:a62:1ad3:0:b029:19d:cc02:5d07 with SMTP id a202-20020a621ad30000b029019dcc025d07mr18174461pfa.70.1607460586552; Tue, 08 Dec 2020 12:49:46 -0800 (PST) x-topics: [EE] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 The AC path is adjacent and parallel to the 3.3V bus; the motor current will be coupled into that bus to some extent. I would carry the 5V closer to the microcontroller and add another linear 3.3V regulator there. That way everything else that happens on the 3.3V bus won't intrude so easily. --=20 James Cameron http://quozl.netrek.org/ --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .