2 layers114.9 × 76 mm
Protected power entry
absmach/synth
Open-source circuit compiler for engineers and AI agents
84 parts29Apache-2.0
2 layers41 × 32.2 mm
Usb uart
absmach/synth29Open-source circuit compiler for engineers and AI agents
- Size
- 41 × 32.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 36
- Nets
- 26
- Pads
- 130
- Tracks, vias
- 273, 43
- Pours
- 6
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 9 Sep 2026
- Updated
- 6 Nov 2026
Overview
Usb uart is an open-source printed circuit board by absmach, from the absmach/synth repository on GitHub, published under the Apache-2.0 licence. It is a 2-layer board of 41 × 32.2 mm with 36 parts on 26 nets, routed with 273 tracks and 43 vias.
It is built around the THVD1450D, RS485 and CH342F, with the LP5907MFX-3.3, PTVS6V0S1UR and PRTR5V0U2X among its other parts. Its parts include 9 resistors, 7 diodes, 6 capacitors, 4 connectors and 3 ICs. It belongs with the interfaces and adapters boards of this library.
Main components
9
THVD1450D
SOIC-8-40℃~+125℃ 1 1 256 3V~5.5V 3mA 50Mbps Half-Duplex Transceiver ±18kV SOIC-8 RS-485 / RS-422 ICs ROHSTexas InstrumentsRS-485 / RS-422 ICs
RS485
SOP-81 1 1.2mA 2.5Mbps 256 5V Half-Duplex Transceiver ±4kV SOP-8 RS-485 / RS-422 ICs ROHSGRRS-485 / RS-422 ICs
CH342F
QFN-24-EP(4x4)-40℃~+85℃ 15mA 160uA 2 3.3V、5V 3Mbps USB 2.0 USB to serial QFN-24-EP(4x4) USB Converters ROHSWCH (Nanjing Qinheng Microelectronics)USB Converters
LP5907MFX-3.3
SOT-23-5-40℃~+125℃@(Tj) 1 10uVrms 12uA 250mA 250mV@(250mA) 3.3V 5.5V 82dB@(1kHz) Fixed Positive Short Circuit Protection、Thermal shutdown、Enable control、Input under-voltage protection、Output discharge SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
PTVS6V0S1UR
SOD-123ESD And Surge Protection (TVS/ESD)FUXINSEMI
PRTR5V0U2X
SOT-143-55℃~+125℃ 0.3pF、0.8pF 100W 10V、15V 5V 6.5V 6A 80nA ESD IEC 61000-4-2、IEC 61000-4-5、IEC 61000-4-4 Three channels Unidirectional SOT-143 ESD and Surge Protection (TVS/ESD) ROHSTECH PUBLICESD And Surge Protection (TVS/ESD)
LTST-C190KRKT
0603-30℃~+85℃ 130° 20mA 2V 62.5mW 631nm 639nm 99mcd Discrete Diode Red Water Clear 0603 LED Indication - Discrete ROHSLite-OnLED Indication - Discrete
TYPE-C-31-M-12
SMD-30℃~+80℃ 1 10,000 cycles 16P 20V 5A 7.35mm Female Surface Mount, Right Angle Type-C SMD USB Connectors ROHSHRO ElectronicsUSB ConnectorsLTST-C190KGKT
0603-30℃~+85℃ 130° 20mA 2V 35mcd 567.5nm~576.5nm 574nm 75mW Discrete Diode Water Clear Yellow Green 0603 LED Indication - Discrete ROHSLite-OnLED Indication - Discrete
README
examples/rp2350/README.mdRP2350 routed example
Latest regenerated run
The full-board reconstruction routes with the installed FreeRouting pipeline
on six layers. Local generated artifacts are under
reproductions/rp2350-reconstructed/generated/:
rp2350_devboard_reconstructed.synth— reconstructed Synth sourcerp2350_devboard_reconstructed.layout.toml— recovered placement sidecarrp2350_devboard_freerouted_6layer.kicad_pcb— routed KiCad boardrp2350_devboard_freerouted_6layer.png— rendered review imagefreerouted-6layer-drc.rpt— native KiCad DRC report
FreeRouting completed with 0 unrouted signal nets. The DRC report still contains 14 ground-zone island items and two footprint-library warnings; this is not production sign-off until those items are reviewed.
rp2350_devboard_freerouting_clean.kicad_pcb is a pre-generated compact KiCad
review artifact.
Reference dimensions: approximately 84.5 × 73.1 mm.
Open the KiCad board for an interactive review.
The companion DRC report records the current review state. The authoritative KiCad check currently reports 80 DRC violations and 18 unconnected items. The 18 unconnected entries are zone-to-zone ground-island reports, not ordinary signal-pad pairs, but they are still violations. This is an example and review fixture, not production sign-off; silkscreen and footprint library warnings also require engineering review.
Parts
36| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | (no value) | MountingHole:MountingHole_2.5mm | H1, H2, H3, H4 |
| 4 | 100nF | Capacitor_SMD:C_0603_1608Metric | C4, C5, C6, C7 |
| 3 | 470 | Resistor_SMD:R_0603_1608Metric | R3, R4, R7 |
| 3 | TVS | Diode_SMD:Nexperia_CFP3_SOD-123W | D2, D5, D6 |
| 2 | 10k | Resistor_SMD:R_0603_1608Metric | R8, R9 |
| 2 | 1k | Resistor_SMD:R_0603_1608Metric | R5, R6 |
| 2 | 2.2uF | Capacitor_SMD:C_0603_1608Metric | C2, C3 |
| 2 | 5.1k | Resistor_SMD:R_0603_1608Metric | R1, R2 |
| 1 | 120ohm | Resistor_SMD:R_0603_1608Metric | R_TERM |
| 1 | 4.7k | Resistor_SMD:R_0603_1608Metric | R_TNOW |
| 1 | CH342F | Package_DFN_QFN:QFN-24-1EP_4x4mm_P0.5mm_EP2.6x2.6mm | U1 |
| 1 | FLOW1 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J3 |
| 1 | LDO | Package_TO_SOT_SMD:SOT-23-5 | U2 |
| 1 | RS485 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J4 |
| 1 | THVD1450D | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U3 |
| 1 | TVS | Package_TO_SOT_SMD:SOT-143 | D1 |
| 1 | TX0 | LED_SMD:LED_0603_1608Metric | D4 |
| 1 | TX1 | LED_SMD:LED_0603_1608Metric | D7 |
| 1 | TYPE-C-31-M-12 | Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
| 1 | UART1 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J2 |
| 1 | VIO | LED_SMD:LED_0603_1608Metric | D3 |
| 1 | VIO_SEL | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J_VIO |
Questions
How big is the Usb uart PCB?
It measures 41 × 32.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Usb uart use?
36 parts, built around the THVD1450D, RS485, CH342F and LP5907MFX-3.3. 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 Usb uart KiCad files?
From the absmach/synth repository on GitHub, at the commit this page was made from: the board is qualification/class-b/usb-uart/kicad/usb_uart.kicad_pcb and its schematic qualification/class-a/i2c-sensor-node/export/i2c_sensor_node.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Usb uart design in my own project?
Its repository publishes it under the Apache-2.0 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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