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Sender: "piclist-bounces@mit.edu" Date: Mon, 20 Apr 2020 03:01:57 -0700 Subject: Re: [EE] LDO reg keeps failing. Looking for suggestions. Thread-Topic: [EE] LDO reg keeps failing. Looking for suggestions. Thread-Index: AdYW/FKFJVTuJJnHRb+HPpKmCknRvA== Message-ID: References: <20200420073653.GL12237@laptop.org> List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: 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 packetflux.com designates 209.85.167.42 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.167.42; helo=mail-lf1-f42.google.com; dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=packetflux-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=wfzIUu304hDonGc7u/g+hBnG8mQfcmAhigjcnLKAsys=; b=Dssp3pjlvuhC9jFtUoyEw01G7TNbOW5r/CGzewg1yYv4vq3X+zt3mvLDHJsSMTiMK5 pz9DySVSSYoBagrA2NryrYA7x/AzQR7H2+DQHSguV6Dg2liYTi46nzxlKtcs7hBmUVzI d0XRTLCxUx4wti6vptoW65Bz7X7NvtbnMywmxoxD85Ni5pWve/i9MX4vYllBBHrtM9Rx LzW2vNRJrcRnCdxzsoNthm1Gt2XfWdFEuOwPA/jdaA6zj4gMC+2dCLG46fspfW+G9WKR 3/9wJI9Xsfh5jTDZ6T3vf2fvbW10DxAjSZNEVsAGUmDeEe6lqDFu+G4zbWSixhxlf+18 baOA== authentication-results: spf=pass (sender IP is 209.85.167.42) smtp.mailfrom=packetflux.com; mit.edu; dkim=pass (signature was verified) header.d=packetflux-com.20150623.gappssmtp.com; mit.edu; dmarc=bestguesspass action=none header.from=packetflux.com;compauth=pass reason=109 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:a19:f719:: with SMTP id z25mr10294362lfe.63.1587376928485; Mon, 20 Apr 2020 03:02:08 -0700 (PDT) x-topics: [EE] x-content-filtered-by: Mailman/MimeDel 2.1.6 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 I was just going to suggest that as it isn't there. Diode across the regulator 'pointing' at the input (Vcc) is the correct direction. I'm also wondering about the reverse body diode in the top fet couping emf into Vdd which would cause it to rise somewhat. I don't know enough about your motors to know if this is a possibility or not. On Mon, Apr 20, 2020 at 3:58 AM RussellMc wrote: > On phone. > Can't display diagram. > Is there a reverse biased diode across regulator from input to output > > > > > > Russell > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 - Forrest --=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 .