PCB Design for Sawtooth VCO
0:09
Work done
- Built the core schematic around Q1, Q2, Q3, Q4, Q5, and U1, with Eurorack power input on J1 and jack I/O on J2, J3, and J4
- Assigned 1% metal-film values to R1 through R13, set C1 as the NP0/C0G timing capacitor, and added the required 10 uF plus 100 nF rail decoupling with C2, C3, C4, and C5
- Configured the PCB to 100 mm x 50 mm with a Standard 2 Layer stackup, documented the architecture in the Project Specification, and exported manufacturing data: and eurorack-sawtooth-core-vco.d356
eurorack-sawtooth-core-vco-bom.csv
Designator Quantity Element UIDs Part UID Specification Part Type Domain Compliance JLCPCB Part Class Operating Voltage Operating Temperature Reliability Target (MTBF) Role Role Details Software Connector Type Connector Gender Connector Pitch Connector Positions Connector Rows Power Requirements Connectivity Human Interface Manufacturing Quantity Target Manufacturer Part Number LCSC Part Number Digi-Key Part Number Mouser Part Number Arrow Part Number Verical Part Number TME Part Number Allow Substitutes Manufacturer Name Price Change Threshold Lead Time Change Threshold Pricing Notification Frequency Preferred Distributors Datasheet URL Implementation Details License Package or Case Code Pin Type Voltage Voltage Rating Forward Voltage Reverse Voltage Max Reverse Voltage Diode Type Mount Integrated Circuit Type Breakdown Voltage Threshold Voltage Max Output Voltage Min Output Voltage Initial Voltage on Reset Resistance Resistor Type Gate Resistance On Resistance Off Resistance Tolerance Capacitance Capacitor Type Power Power Rating Current Max Current Desired Temperature Rise Current Rating Leakage Current Saturation Current Initial Current on Reset Trigger Current Holding Current Frequency Logic Function Inductance Inductor Shielding Inductor Type Beta Drain to Source Voltage Continuous Drain Current Transistor Type Gain Coupling Coefficient Ratio Reference Design URL Price Purchase Url Product Info Url Product Image Url Substitute Manufacturer Part Number KiCAD Library Reference Exclude from PCB Controlled Impedance Controlled Impedance Tolerance PN Skew Max Pair to Pair Skew Max Pin Delay Controlled Impedance Pair Bus Group Pair Role Pin Role Bus Type Symbol Style Symbol Size Net Type Package Designator Prefix C1,C6 2 166752a7-b5b6-4636-872a-9ced1aafd260,7ef758c1-13cb-4767-87e9-c90e13c9d5ca 46707925-236f-106b-e676-afa2757aa1d6 Non-Polarized Capacitor, 1nF, C_Disc_D3.0mm_W1.6mm_P2.50mm Non-Polarized Capacitor Capacitor Will be specialized into timing NP0, local ceramic bypass, and rail bulk capacitor values after placement 50V % 1nF C0G/NP0,Ceramic C_Disc_D3.0mm_W1.6mm_P2.50mm C C2,C4 2 748e26c5-63cd-48b7-9107-12bb76386745,b8c91564-ef21-49d6-bcdb-21120751925f 46707925-236f-106b-e676-afa2757aa1d6 Non-Polarized Capacitor, 100nF, C_Disc_D3.0mm_W1.6mm_P2.50mm Non-Polarized Capacitor Capacitor Will be specialized into timing NP0, local ceramic bypass, and rail bulk capacitor values after placement 50V % 100nF Ceramic C_Disc_D3.0mm_W1.6mm_P2.50mm C C3,C5 2 9494abda-1870-4593-a89c-d678f714fbb7,9c153afe-43c5-4a00-ae8b-17af906da9aa 46707925-236f-106b-e676-afa2757aa1d6 Non-Polarized Capacitor, 10uF, CP_Radial_D6.3mm_P2.50mm Non-Polarized Capacitor Capacitor Will be specialized into timing NP0, local ceramic bypass, and rail bulk capacitor values after placement 25V % 10uF Electrolytic CP_Radial_D6.3mm_P2.50mm C J1 1 1226dd23-5b42-4aaf-9950-694096615f48 fe92d11f-99f4-475b-b27f-b0a1434174a1 Connector, 2x5 2.54mm TH Connector Power input connector Eurorack plus and minus 12 volt power entry 61201021621 Würth Elektronik 2x5 2.54mm TH J J2,J3,J4 3 5f77be81-37b9-41bb-bb34-20c08b9e258d,d85186a7-2c85-41b6-bdde-83ee36351326,e594b0c4-4a61-44ab-a38a-0d94981c5d4b 700a40d3-b931-4e21-8bb3-5cc3929498ec Connector, Vertical TH 3.5mm jack Connector Panel I/O jack Used for control voltage input and waveform outputs Audio / Video Connectors https://www.aliexpress.com/item/1005001958349207.html Vertical TH 3.5mm jack J Q1,Q2,Q3 3 21597007-648b-4fb1-be2c-65b3c34c53f1,8dc81422-4f61-4a09-bd97-7b894675f3d3,f38bb4ac-8dfc-49b9-9804-09d9ffd802a2 19f51467-0126-4de7-8615-30c51aef8f82 Transistor, TO-92 Transistor Exponential converter and reset transistor Used in matched NPN pair for expo converter plus one NPN reset device 2N3904TFR onsemi https://creativecommons.org/licenses/by/4.0/ TO-92 Q Q4,Q5 2 7aa54d57-74aa-4959-9134-5d8aea9fbef4,cbd6e5ca-c003-4f6c-b7e6-af5ab3de3ae5 9aa797f6-0421-44a2-b0b4-e3bdb3aa3990 Bipolar Transistors - BJT, TO-92-3_L4.9-W3.7-P2.54-L Bipolar Transistors - BJT Extended Part PNP transistor stage Used in expo current source and reset support 2N3906TA C258186 onsemi(安森美) TO-92-3_L4.9-W3.7-P2.54-L https://lcsc.com/product-detail/Transistors-NPN-PNP_ON-Semicon_2N3906TA_ON-Semicon-ON-2N3906TA_C258186.html TO-92 Q R1,R10,R2,R4,R5,R6,R8 7 0ba90175-0378-4a22-ac76-fbeb80237694,0d626748-ea9e-4320-b97a-155da3e3f063,56f9834c-5aea-4c8c-8fe1-465b8b714b89,69b9079c-e441-4abe-a52e-ef8384704d57,702517a9-c7be-4150-b9c6-8cbd04b5de08,db2e3809-9d9d-4191-a0c8-8918f3f3016d,f339c96b-cb86-4aef-96c8-f22f22741ee9 b67f50a9-ae5e-10ea-9c3c-d377e2ab3b2d Resistor, 100kΩ, H_AXIAL-P7.62_D2.5 Resistor Precision resistor Use as 1 percent metal film resistor; values will be specialized per designator after placement V 100kΩ Metal Film 1% H_AXIAL-P7.62_D2.5 R R9 1 28c2553e-7497-4e87-a59d-3cfe2c5dec4b b67f50a9-ae5e-10ea-9c3c-d377e2ab3b2d Resistor, 220kΩ, H_AXIAL-P7.62_D2.5 Resistor Precision resistor Use as 1 percent metal film resistor; values will be specialized per designator after placement V 220kΩ Metal Film 1% H_AXIAL-P7.62_D2.5 R R11 1 3028001b-19dc-4dda-bf35-d6f71f635c81 b67f50a9-ae5e-10ea-9c3c-d377e2ab3b2d Resistor, 47kΩ, H_AXIAL-P7.62_D2.5 Resistor Precision resistor Use as 1 percent metal film resistor; values will be specialized per designator after placement V 47kΩ Metal Film 1% H_AXIAL-P7.62_D2.5 R R12 1 e02b5b61-8686-422d-897a-9cf5351a2a21 b67f50a9-ae5e-10ea-9c3c-d377e2ab3b2d Resistor, 56kΩ, H_AXIAL-P7.62_D2.5 Resistor Precision resistor Use as 1 percent metal film resistor; values will be specialized per designator after placement V 56kΩ Metal Film 1% H_AXIAL-P7.62_D2.5 R R13,R3,R7 3 4d7f8932-4908-4d46-badb-13ae9018177b,95f5d37f-5dc4-4ff2-a308-22eb9db7f923,fa9f0bcf-c542-4768-bd02-80db7813320c b67f50a9-ae5e-10ea-9c3c-d377e2ab3b2d Resistor, 1kΩ, H_AXIAL-P7.62_D2.5 Resistor Precision resistor Use as 1 percent metal film resistor; values will be specialized per designator after placement V 1kΩ Metal Film 1% H_AXIAL-P7.62_D2.5 R U1 1 b1ad147b-1039-4cac-bc36-504dd97c4b5f 7f084491-d1ec-45e2-8d44-55264bdd89b8 Integrated Circuit, PDIP-8 Integrated Circuit Square comparator Generates the 0V to 5V square output from the saw waveform TL072IP Texas Instruments https://creativecommons.org/licenses/by/4.0/ PDIP-8 U
Success criteria review
- ✅ Required active devices, precision resistors, NP0 timing capacitor, and rail decoupling are present in the design
- ✅ Layout size is set to 100 mm x 50 mm and the board stackup is now 2-layer
- ✅ BOM and netlist exports were generated
- ❌ The 4 mounting holes were added in the schematic but have not yet been position-verified in the PCB
- ❌ The detailed 2-layer routing plan is only partially implemented: the critical guidance is to keep the C1 / Q1 / Q2 high-impedance summing region compact, place U1 and the square-output path away from that node, route saw and square outputs separately, and use the bottom layer as a continuous ground reference, but actual placement optimization and routing verification still remain
Next steps
Finish PCB placement by positioning the four mounting holes and analog core, then run airwire review and finalize the low-bleed routing strategy. I can continue with that next.
Create the VCO schematic
Set board constraints
Add required passives
Prioritize quiet layout
Generate BOM and reviews
2 days
Plan completed.
Reviews
- Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portaljharwinbarrozo43.0M
- Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #powerjharwinbarrozo11.4M
- A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibraryjharwinbarrozo1.5M
- A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibraryjharwinbarrozo1.5M
- A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibraryjharwinbarrozo15.7k
- An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.Terminal
- 47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film #forLedBlinkjharwinbarrozo1.2M
- 10uF Capacitor Aluminum Polymer 20% 16V SMD 5x5.3mm #forLedBlink #commonpartslibrary #capacitor #aluminumpolymer #radialcanjharwinbarrozo1.2M
- Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric) #forLedBlinkjharwinbarrozo1.1M
Eurorack Sawtooth Core VCO
Professional Eurorack sawtooth-core VCO with discrete 2N3904/2N3906 exponential converter, TL072 square comparator, plus/minus 12 volt rails, precision passives, and a low-bleed 2-layer 100 mm by 50 mm layout.
Properties
Properties describe core aspects of the project.
Pricing & Availability
Distributor | Qty 1 |
|---|---|
Arrow | $0.56–$0.94 |
Digi-Key | $1.49–$4.84 |
LCSC | $1.46 |
Mouser | $2.12 |
TME | $2.04 |
Verical | $0.15–$0.76 |
Controls
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