2 layers125 × 56 mm
ML2
brucemack/microlink
An open source EchoLink/AllStarLink implementation that runs on a simple microcontroller.
73 parts18GPL-3.0
2 layers100 × 59 mm
An open source EchoLink/AllStarLink implementation that runs on a simple microcontroller.
- Size
- 100 × 59 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 65
- Nets
- 42
- Pads
- 166
- Tracks, vias
- 209, 27
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 23 Jan 2024
- Updated
- 28 Oct 2025
Overview
ML0 is an open-source printed circuit board by brucemack, from the brucemack/microlink repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 100 × 59 mm with 65 parts on 42 nets, routed with 209 tracks and 27 vias.
It is built around the LMV321, LMV324 and LTV-356T, with the BAT54S among its other parts. Its parts include 20 capacitors, 20 resistors, 6 ICs, 5 connectors and 2 diodes. It belongs with the radio and wireless boards and the RP2040 boards of this library.
Main components
4
LMV321
SOT-23-5L-2.75V~-1.25V、1.25V~2.75V 0℃~+70℃ 1 10pA 10pA 1MHz 2.1V~5.5V 20mA 20nV/√Hz@10kHz 520V/ms 60uA 70dB 800uV Built-in compensation Rail-to-Rail Input, Rail-to-Rail Output SOT-23-5L Operational Amplifier ROHSJiangsu Changjing Electronics Technology (CJ)Operational Amplifier
LMV324
SOP-14-40℃~+85℃ 1MHz 2.8dB 250nA 3V~5.5V 4 400V/ms 40mA 40uV/√Hz@1kHz 430uA 5nA 7mV Built-in compensation、ESD protection SOP-14 Operational Amplifier ROHSIDCHIPOperational Amplifier
LTV-356T
SOP-4-2.54mm-55℃~+110℃ 1 1.2V 200mV@1mA,20mA 3.75kV 3us 4us@2mA,100Ω 50% 50mA 50mA 600% 6V 80V DC Phototransistor SOP-4-2.54mm Transistor, Photovoltaic Output Optoisolators ROHSLite-OnTransistor, Photovoltaic Output Optoisolators
BAT54S
SOT-231 Pair Series Connection 1V@100mA 200mA 2uA@25V 30V 600mA SOT-23 Schottky Diodes ROHSMDDSchottky Diodes
README
hw/ML3/README.mdThis file contains the details for the version 3 (ML3) of the MicroLink hardware. This is the first version that has a real enclosure so we are paying more attention to mechanical detail.
Enclosure Considerations
Connectors That Penetrate the Enclosure
- DC power connector - 5.5mm jack, male center pin positive.
- Signal/audio connector - DB9, female.
Indicators That Penetrate the Enclosure
- Three indicator LEDs - D1 Red, D3 blue, D4 green
Thermal
- The 3.3V LDO gets warm so there should be airflow in that vicinity
Change Log (V3)
R1 (17-Apr-2024)
- Moved Pi Pico W daughter card up by 1.00mm.
- Moved clear area under Pi Pico W daughter card up by 0.75mm.
- Moved J2 (5.5mm power jack) up by 2.5mm.
- Moved J1 (DB9) right by 2.5mm.
DRC Notes:
- There are 12 warnings: "Silkscreen clipped by board edge."
Parts
65| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 0.1u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C5, C18, C21, C29 |
| 4 | MountingHole | MountingHole:MountingHole_4mm | H1, H2, H3, H4 |
| 3 | 100u | KiCad-Library:CAP_KEMET_530_530 | C1, C6, C20 |
| 3 | 10k | KiCad-Library:POT_3362P | RV1, RV3, RV4 |
| 3 | 10u | KiCad-Library:CAP_KEMET_530_530 | C7, C8, C9 |
| 3 | 1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R3, R9, R19 |
| 3 | 2.2k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R12, R13, R14 |
| 2 | 0R | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8, R18 |
| 2 | 1.5k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R15 |
| 2 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R5, R6 |
| 2 | 10n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4, C27 |
| 2 | 2.7k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R2, R17 |
| 2 | 22n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C3, C26 |
| 2 | 270k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R10, R11 |
| 2 | 47u | KiCad-Library:CAP_KEMET_530_530 | C19, C24 |
| 2 | LTV-356T | Package_SO:SO-4_4.4x3.6mm_P2.54mm | U2, U5 |
| 2 | Transformer_1P_1S | KiCad-Library:CheapAudioTransformer | T1, T2 |
| 1 | 12V Supply | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J2 |
| 1 | 1u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C17 |
| 1 | 200 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4 |
| 1 | 220 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R7 |
| 1 | 22k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R16 |
| 1 | 47u (Optional DC Block) | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C10 |
| 1 | 570 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R20 |
| 1 | ADC Connector | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J4 |
| 1 | AF Out | TestPoint:TestPoint_Pad_2.5x2.5mm | TP1 |
| 1 | BAT54S | Package_TO_SOT_SMD:SOT-23 | D2 |
| 1 | Conn_01x03 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J5 |
| 1 | Conn_01x06 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J1 |
| 1 | DAC Address Control | Jumper:SolderJumper-2_P1.3mm_Bridged_Pad1.0x1.5mm | JP1 |
| 1 | Digital Connector | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J3 |
| 1 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1 |
| 1 | LMV321 | Package_TO_SOT_SMD:SOT-23-5_HandSoldering | U1 |
| 1 | LMV324 | Package_SO:TSSOP-14_4.4x5mm_P0.65mm | U9 |
| 1 | MCP4725xxx-xCH | Package_TO_SOT_SMD:SOT-23-6 | U4 |
| 1 | NC | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C22 |
| 1 | NCP1117-3.3_SOT223 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U3 |
| 1 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP2 |
Questions
How big is the ML0 PCB?
It measures 100 × 59 mm and has 2 copper layers, 1.6 mm thick.
What parts does the ML0 use?
65 parts, built around the LMV321, LMV324, LTV-356T and BAT54S. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the ML0 KiCad files?
From the brucemack/microlink repository on GitHub, at the commit this page was made from: the board is hw/ML0/ML0.kicad_pcb and its schematic hw/ML0/AudioIn.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ML0 design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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