GPSDO
About the GPSDO PCB
GPSDO is an open source PIC PCB design by dewayne57, published on GitHub under the Apache-2.0 license. It is a 2-layer board measuring 203.2 × 152.4 mm, with 157 components from 115 distinct parts.
Its main chip is the 24AA02-OT, from the PIC family. Other key parts include the LM7912, LM2574N-3.3, LM2596T-5, DAC8571IDGK and NEO-M8M. By type, the board carries 36 resistors, 29 capacitors, 20 diodes, 19 connectors, 16 ICs and 11 test points.
It belongs with the rf & radio designs in this gallery.
From the project
GPS Disciplined Oscillator
This repository contains a hardware and firmware design for a GPS-disciplined oscillator (GPSDO). The system uses a local oven-controlled crystal oscillator (OCXO) disciplined by a GPS reference (1PPS and time) via a digital control loop implemented on a PIC microcontroller.
Purpose: provide a compact, buildable GPSDO that combines the short-term stability of an OCXO with the long-term accuracy of GPS. The design favors through-hole assembly and flexible OCXO support so hobbyists and technicians can adapt the board to available oscillators.
Main components on the GPSDO
GPSDO bill of materials (BOM)
157 components, 115 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | LM7912 | TO-220-3_Vertical | U201 |
| 1 | LM2574N-3.3 LM2596T-5 | TO-220-5_P3.4x3.7mm_StaggerOdd_Lead3.8mm_Vertical | U202 |
| 1 | LM2596T-5 LM2596T-12 | TO-220-5_P3.4x3.7mm_StaggerOdd_Lead3.8mm_Vertical | U203 |
| 1 | DAC8571IDGK | MSOP-8_3x3mm_P0.65mm | U301 |
| 1 | NEO-M8M OP07 | SOIC-8_3.9x4.9mm_P1.27mm | U302 |
| 1 | OP07 | SOIC-8_3.9x4.9mm_P1.27mm | U303 |
| 1 | OP07 GALI-52 | SOT-89-3 | U304 |
| 1 | TXS0108EPW 74LVC1G17 | SOT-353_SC-70-5 | U305 |
| 1 | GALI-52 74LVC1G17 | SOT-353_SC-70-5 | U306 |
| 1 | 74LVC1G17 MAX232 | DIP-16_W7.62mm_LongPads | U307 |
| 1 | 74LVC1G17 MCP23017_SO | SOIC-28W_7.5x17.9mm_P1.27mm | U308 |
| 1 | MCP23017_SO 24AA04 | SOIC-8_5.3x6.2mm_P1.27mm | U309 |
| 1 | 24AA02-OT PIC18F27Q43 | SOIC-28W_7.5x18.7mm_P1.27mm | U310 |
| 1 | PIC18F27Q43 FT232RL | SSOP-28_5.3x10.2mm_P0.65mm | U311 |
| 1 | ADCMP600 | SOT-23-5 | U401 |
| 1 | 74LVC1G17 | SOT-353_SC-70-5 | U402 |
| 1 | 2N3904 | TO-92L_HandSolder | Q301 |
| 1 | IsoTemp 131 | ISOTEMP 131 | X401 |
| 1 | Bliley N47/NV47 | Bliley N47 | X402 |
| 1 | IsoTemp 143N | ISOTEMP 143N | X403 |
Show 95 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | VECTRON C4550A | VectronC4550-A | X404 |
| 1 | Oscilloquartz 8663 | OQ8663 | X405 |
| 1 | IsoTemp 143A | ISOTEMP 143A | X406 |
| 1 | Line | Amp Faston 250 THT | J201 |
| 1 | Earth | Amp Faston 250 THT | J202 |
| 1 | Neutral | Amp Faston 250 THT | J203 |
| 1 | 44472-0453 | 44472-04YY | J204 |
| 1 | Encoder | PinHeader_1x06_P2.54mm_Vertical | J302 |
| 2 | Ref Select | PinHeader_1x03_P2.54mm_Vertical | J303, J314 |
| 1 | GPS Module | PinHeader_1x05_P2.54mm_Vertical | J304 |
| 1 | VCO Range | PinHeader_1x03_P2.54mm_Vertical | J305 |
| 1 | LCD | PinHeader_1x14_P2.54mm_Vertical | J306 |
| 1 | Serial | PinHeader_1x10_P2.54mm_Vertical | J307 |
| 1 | RF 50 Ohm | SMA_Amphenol_901-144_Vertical | J308 |
| 1 | RF TTL | SMA_Amphenol_901-144_Vertical | J309 |
| 1 | 1PPS TTL | SMA_Amphenol_901-144_Vertical | J310 |
| 1 | Program | PinHeader_1x02_P2.54mm_Vertical | J311 |
| 1 | ICSP | PinHeader_1x05_P2.54mm_Vertical | J312 |
| 1 | USB | PinSocket_1x05_P2.54mm_Vertical | J313 |
| 1 | OCXO Signal | PinHeader_1x03_P2.54mm_Vertical | J401 |
| 1 | OCXO Voltage | PinHeader_1x03_P2.54mm_Vertical | J402 |
| 1 | CR2302 CR2032 | Battery_Panasonic_CR2032-HFN_Horizontal_CircularHoles | BT301 |
| 2 | 0805L010 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | F301, F302 |
| 1 | Tie | SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP201 |
| 2 | N10SP005M | N10SP005M | RT201, RT202 |
| 3 | MOV-20D241KKTR 150V | MOV20D241KKTR | RV201, RV202, RV203 |
| 1 | 1K | Potentiometer_Bourns_3266W_Vertical | RV301 |
| 1 | B82732R2142 | TDK B82732R Series | T201 |
| 1 | 14A-56-28 FS24-1500 | FS-36VA | T202 |
| 1 | Gnd | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP201 |
| 1 | +16.9 | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP202 |
| 1 | -16.9 | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP203 |
| 1 | -12 | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP204 |
| 1 | +5 | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP205 |
| 1 | +12 | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP206 |
| 1 | VRef | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP301 |
| 1 | VCO | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP302 |
| 1 | RF | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP303 |
| 1 | 1PPS | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP304 |
| 1 | Clock | TestPoint_Bridge_Pitch2.54mm_Drill1.0mm | TP305 |
| 1 | GBU6A | Diode_Bridge_Vishay_GBU | D201 |
| 1 | 1N5819 1N5822 | D_SOD-128 | D202 |
| 1 | 1N5822 | D_SOD-128 | D203 |
| 1 | 1N5819 SS38 | D_SMB_Handsoldering | D301 |
| 3 | SS38 | D_SMB_Handsoldering | D302, D303, D304 |
| 1 | SS38 Red | LED_D3.0mm_Horizontal_O3.81mm_Z2.0mm | D305 |
| 1 | Red | LED_D3.0mm_Horizontal_O3.81mm_Z2.0mm | D306 |
| 3 | Green | LED_D3.0mm_Horizontal_O3.81mm_Z2.0mm | D307, D309, D312 |
| 1 | Yellow | LED_D3.0mm_Horizontal_O3.81mm_Z2.0mm | D308 |
| 2 | SS38 | D_SMB_Handsoldering | D310, D311 |
| 1 | 1N5819 Red | LED_D3.0mm_Horizontal_O3.81mm_Z2.0mm | D313 |
| 4 | 1N4148W | D_SOD-323_HandSoldering | D401, D402, D403, D404 |
| 2 | Bead | L_0805_2012Metric_Pad1.15x1.40mm_HandSolder | FB301, FB302 |
| 1 | 330UH 47uH | Bourns PM5022 | L201 |
| 1 | 47UH 68uH | Bourns PM5022 | L202 |
| 1 | 68UH 3.3uH | Bourns SDE04030 | L203 |
| 1 | 3.3UH 3.3uH | Bourns SDE04030 | L204 |
| 1 | 1 uH | L_1206_3216Metric_Pad1.42x1.75mm_HandSolder | L301 |
| 6 | C731U222MSVDBAWL35 2200 | C731U222MSVDBAWL35 | C201, C202, C203, C204, C205, C206 |
| 4 | 2000 | CP_Elec_18x22 | C207, C208, C209, C210 |
| 2 | 330 | CP_Elec_10x10.5 | C211, C213 |
| 1 | 220 330 | CP_Elec_10x10.5 | C212 |
| 1 | 330 150 | CP_Elec_10x10 | C214 |
| 1 | 220 150 | CP_Elec_10x10 | C215 |
| 4 | 100n | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C301, C303, C309, C313 |
| 1 | 100N 47 | CP_Elec_8x6.9 | C302 |
| 1 | 100N 100n | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C304 |
| 2 | 0.1 | CP_Elec_4x5.4 | C305, C307 |
| 2 | 0.1 | CP_Elec_4x5.4 | C306, C308 |
| 1 | 4.7 | CP_Elec_6.3x5.4 | C310 |
| 1 | 47 | CP_Elec_8x6.9 | C311 |
| 1 | 0.1 | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C312 |
| 1 | 220P 220p | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C401 |
| 2 | 4.7K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R201, R202 |
| 1 | 2.2K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R203 |
| 2 | 1 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R204, R205 |
| 1 | 22K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R206 |
| 1 | 10K 47K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R207 |
| 1 | 3.3 51.1K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R301 |
| 3 | 51.1K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R302, R303, R304 |
| 1 | 51.1K 330 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R305 |
| 1 | 4.7K 150 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R306 |
| 1 | 330 2.2K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R307 |
| 2 | 150 8.55 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R308, R312 |
| 1 | 2.2K 142 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R309 |
| 1 | 8.55 150 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R310 |
| 1 | 142 150 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R311 |
| 1 | 150 330 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R313 |
| 1 | 8.55 330 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R314 |
| 5 | 330 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R315, R316, R317, R318, R319 |
| 1 | 330 4.7K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R320 |
| 1 | 330 10K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R321 |
| 2 | 4.7K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R322, R323 |
| 2 | 470 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R401, R406 |
| 4 | 100K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R402, R403, R404, R405 |
GPSDO design files
The KiCad project lives in the dewayne57/GPSDO repository on GitHub; these links point at the commit this page was built from.
- LayoutHardware/GPSDO.kicad_pcb
- SchematicHardware/GPSDO.kicad_sch
- BOMHardware/GPSDO.csv
GPSDO: common questions
What microcontroller does the GPSDO use?
The GPSDO is built around the 24AA02-OT, from the PIC family.
How big is the GPSDO PCB?
The GPSDO measures 203.2 × 152.4 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the GPSDO?
157 components, from 115 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the GPSDO design files?
From the dewayne57/GPSDO repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the GPSDO design in my own project?
Yes, under the terms of its Apache-2.0 license, which dewayne57 chose for the repository.
Can I test firmware for the GPSDO without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug PIC firmware against it before you order a PCB.
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