{ "guild": { "id": "1361349522684510449", "name": "wafer.space Community", "iconUrl": "2025-10_media/fb143eaa45770cbb40493d09b625e98b-09FD1.png" }, "channel": { "id": "1408135265427394661", "type": "GuildTextChat", "categoryId": "1409664731760955403", "category": "\uD83D\uDCD0 - Designing", "name": "\uD83D\uDD70️-analog", "topic": null }, "dateRange": { "after": "2025-09-30T23:59:59.999+00:00", "before": "2025-11-01T00:00:00+00:00" }, "exportedAt": "2026-07-08T06:54:52.1308047+00:00", "messages": [ { "id": "1425663911406862337", "type": "Default", "timestamp": "2025-10-09T01:59:24.034+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "ooh, so it's basically close to a 3.58 mhz bandpass filter? :3", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1425700758694658099", "type": "Default", "timestamp": "2025-10-09T04:25:49.112+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "If you are looking for example projects and designs, mostly in analog, take a look at https://vlsidesignlab.org. The site has several years of project websites and videos of the VLSI design lab class at Columbia University where students design a chip in the spring, it gets fabricated in summer, and they test it in fall. There is quite a bit of design information available, and there is a search and index also. Have fun!", "author": { "id": "853313068871188530", "name": "peterkinget", "discriminator": "0000", "nickname": "peterkinget", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/3-FB033.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1426213521422815293", "type": "Default", "timestamp": "2025-10-10T14:23:21.273+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "Question... Is it reasonable to try to implement an Operational Transconductance Amplifier in the target process? - something in the vein of LM13700 ( https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ti.com/lit/ds/symlink/lm13700.pdf&ved=2ahUKEwiOqube6ZmQAxWEj4kEHSjgB54QFnoECBkQAQ&usg=AOvVaw3GXAglJwE-LG-Gg1gfRkxv )... if yes, I imagine it might have tighter limits on currents/voltage/wattage?", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1426374309911335022", "type": "Reply", "timestamp": "2025-10-11T01:02:16.236+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "@Tim Edwards - Any thoughts on @madbrain's question?", "author": { "id": "169786952432746498", "name": "mithro_", "discriminator": "0000", "nickname": "Tim 'mithro' Ansell", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/9679bb77da48d47c905b398d98a83780-75B68.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [ { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, { "id": "1365118310701600900", "name": "rtimothyedwards_19428", "discriminator": "0000", "nickname": "Tim Edwards", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/6bcc8e61db497b620550682309ace5d5-D89B4.png" } ], "reference": { "messageId": "1426213521422815293", "channelId": "1408135265427394661", "guildId": "1361349522684510449" }, "inlineEmojis": [] }, { "id": "1427200882931400774", "type": "Reply", "timestamp": "2025-10-13T07:46:46.601+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "You won't have anything like the supply range of the 13700, which is over 30 volts (from memory). If that isn't an issue then there is nothing to stop you making such a circuit while also including extra circuits like a voltage-controlled input for gm control. I used a similar process for a 4MHz gm-C bandpass filter many years ago with good results, and there are many MOS 'tricks' that you can use to get significantly lower distortion than the 13700 has.", "author": { "id": "732905260091310090", "name": "valgamaa", "discriminator": "0000", "nickname": "Valgamaa", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/3-FB033.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [ { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" } ], "reference": { "messageId": "1426213521422815293", "channelId": "1408135265427394661", "guildId": "1361349522684510449" }, "inlineEmojis": [] }, { "id": "1427201726154408007", "type": "Default", "timestamp": "2025-10-13T07:50:07.641+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "great to know \uD83D\uDC4D the applications I'm looking into are boutique synthesizers so the S-curve shaped distortion is often a feature rather than a bug \uD83D\uDE09", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [ { "id": "", "name": "\uD83D\uDC4D", "code": "thumbsup", "isAnimated": false, "imageUrl": "2025-10_media/1f44d-27259.svg" }, { "id": "", "name": "\uD83D\uDE09", "code": "wink", "isAnimated": false, "imageUrl": "2025-10_media/1f609-9EC67.svg" } ] }, { "id": "1427216446047518780", "type": "Default", "timestamp": "2025-10-13T08:48:37.137+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "You won't get a tanh curve, but you will get something similar with MOS transistors. DC offsets might need some consideration and the capacitor options on-chip will be too low density to be much use. Making the circuits differential might give the headroom you will want, and with that gyrators become very simple (that's the key to most filters in CMOS) but I doubt you will want to implement standard filter responses like Butterworth etc. I half-wondered if it might be synthesiser-related when I saw mention of the 13700!", "author": { "id": "732905260091310090", "name": "valgamaa", "discriminator": "0000", "nickname": "Valgamaa", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/3-FB033.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1427223856355213353", "type": "Default", "timestamp": "2025-10-13T09:18:03.892+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "yeah typically for synthesizers the more common filter types are state variable (SVF) and moog-style 4 pole ladder... often deliberately non-linear so that the response doesn't blow up when you crank up the Q-factor... might have to look into having the output current mirrors have a digitally controllable multiplication factor \uD83E\uDD14", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [ { "id": "", "name": "\uD83E\uDD14", "code": "thinking", "isAnimated": false, "imageUrl": "2025-10_media/1f914-15707.svg" } ] }, { "id": "1427244764423655456", "type": "Default", "timestamp": "2025-10-13T10:41:08.764+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "The SSM2044-type topology would map onto this process pretty well, I think. How much experience do you have with MOS circuit design? Most of the blocks you would want for a synthesiser are a really good vehicle to cover most of the circuit topologies that make for good CMOS design. A temperature-insensitive VCO should also be quite practical in this process too.", "author": { "id": "732905260091310090", "name": "valgamaa", "discriminator": "0000", "nickname": "Valgamaa", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/3-FB033.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1427287256338665596", "type": "Default", "timestamp": "2025-10-13T13:29:59.626+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "I'm kindof out of my depth ngl :3 my usual gig is synths in C++ on desktop computers", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1427321156603609193", "type": "Default", "timestamp": "2025-10-13T15:44:42.079+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "(and reverse engineering... including some time on the CEM synthesizer chips which are really all OTA variants similar to lm13700 inside in different arrangements...)", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1428161230907904072", "type": "Default", "timestamp": "2025-10-15T23:22:51.401+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "https://hackaday.com/2025/10/15/more-than-100-sub-circuit-designs-from-texas-instruments/", "author": { "id": "169786952432746498", "name": "mithro_", "discriminator": "0000", "nickname": "Tim 'mithro' Ansell", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/9679bb77da48d47c905b398d98a83780-75B68.png" }, "attachments": [], "embeds": [ { "title": "More Than 100 Sub-Circuit Designs From Texas Instruments", "url": "https://hackaday.com/2025/10/15/more-than-100-sub-circuit-designs-from-texas-instruments/", "timestamp": null, "description": "We were recently tipped off to quite a resource — on the Texas Instruments website, there’s a page where you can view and download a compendium of analog sub-circuits. Individual circui…", "color": "#1A1A1A", "author": { "name": "John Elliot V", "url": "https://hackaday.com/author/johnelliot/" }, "thumbnail": { "url": "2025-10_media/Texas-Instruments-B56DA.jpg", "width": 800, "height": 413 }, "images": [], "fields": [], "inlineEmojis": [] } ], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1429228175019347969", "type": "Default", "timestamp": "2025-10-18T22:02:30.7+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "it's all op amp basic circuits for the most part?", "author": { "id": "316742122751655939", "name": "mrmadbrain", "discriminator": "0000", "nickname": "madbrain", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/1e8f71f13f3da5b168f4886e538778bf-134DE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [], "inlineEmojis": [] }, { "id": "1432427038031220899", "type": "Reply", "timestamp": "2025-10-27T17:53:39.074+00:00", "timestampEdited": null, "callEndedTimestamp": null, "isPinned": false, "content": "That rules. My design class just built in IBM8RF but we did not build it as it was too expensive. Hilariously 8RF was either 130 or 90nm, so the stuff we're doing now. Although it was SOI.", "author": { "id": "323874444344950794", "name": "markemer", "discriminator": "0000", "nickname": "Mark Anderson", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/a976ec32aab182dad158688cea0f5724-4A8BE.png" }, "attachments": [], "embeds": [], "stickers": [], "reactions": [], "mentions": [ { "id": "853313068871188530", "name": "peterkinget", "discriminator": "0000", "nickname": "peterkinget", "color": null, "isBot": false, "roles": [], "avatarUrl": "2025-10_media/3-FB033.png" } ], "reference": { "messageId": "1425700758694658099", "channelId": "1408135265427394661", "guildId": "1361349522684510449" }, "inlineEmojis": [] } ], "messageCount": 14 }