2 layers65 × 56 mm
Industrial hat rpi4
V2gkr/industrial_hat_rpi4
hat to communicate via rs232, rs485, can fd with galvanic isolation
52 parts
4 layers100 × 100 mm
Usb instrument
FynnK/Reflectometer- Size
- 100 × 100 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 74
- Nets
- 69
- Pads
- 282
- Tracks, vias
- 470, 313
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 21 Apr 2026
- Updated
- 2 Jul 2026
Overview
Usb instrument is an open-source printed circuit board by FynnK, from the FynnK/Reflectometer repository on GitHub. It is a 4-layer board of 100 × 100 mm with 74 parts on 69 nets, routed with 470 tracks and 313 vias.
It is built around the LM321, TLV172IDCK and ISO6742, with the BS170 and BSS84 among its other parts. Its parts include 27 resistors, 22 capacitors, 9 ICs, 4 diodes and 4 transistors. It belongs with the ESP32 and RISC-V boards of this library.
Main components
5
LM321
SOT-23-50℃~+70℃ 1 2mV 3nA 400V/ms 40mA 430uA 45nA 90dB SOT-23-5 Operational Amplifier ROHSPJSEMIOperational Amplifier
TLV172IDCK
SC-70-5-18V~-2.25V、2.25V~18V -40℃~+125℃ 1 1.6mA 10MHz 10V/us 10pA 116dB 1uV/℃ 2pA 4.5V~36V 500uV 75mA 9nV/√Hz@1kHz ESD protection Rail-to-rail output SC-70-5 Operational Amplifier ROHSTexas InstrumentsOperational Amplifier
ISO6742
WSON-16-5x4SOP-16-300mil New Arrivals ROHSTexas InstrumentsUncategorised
BS170
TO-92-55℃~+150℃ 1 N-channel 1.2Ω@10V 17pF 2.1V 24pF 500mA 60V 7pF 830mW N-Channel TO-92 MOSFETs ROHSonsemiMOSFETs
BSS84
SOT-23-55℃~+150℃ 1 P-Channel 130mA 2.8pF 24.6pF 2V 3.2Ω@5V 300mW 4.7pF 50V 590pC@10V SOT-23 MOSFETs ROHSDiodes IncorporatedMOSFETs
Parts
74| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 100n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4, C9, C10, C13, C17, C18 |
| 5 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8, R11, R12, R26, R27 |
| 5 | 1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3, R4, R28 |
| 4 | 100 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R29, R30, R34, R36 |
| 4 | 10u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C11, C14, C16, C21 |
| 4 | 1u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C5, C22, C23, C24 |
| 3 | 10n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C2, C19 |
| 3 | 220n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C12, C20, C25 |
| 3 | 47k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R31, R35, R37 |
| 3 | BS170 | Package_TO_SOT_SMD:SOT-23-3 | Q5, Q7, Q8 |
| 3 | LED | LED_SMD:LED_1206_3216Metric | D5, D6, D7 |
| 2 | 4.7k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R18, R19 |
| 2 | 5k1 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R5, R6 |
| 2 | LM321 | Package_TO_SOT_SMD:SOT-23-5 | U12, U13 |
| 1 | 1 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R33 |
| 1 | 100u | Capacitor_SMD:CP_Elec_6.3x5.7 | C15 |
| 1 | 18k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R13 |
| 1 | 22 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R7 |
| 1 | 220 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R14 |
| 1 | 33 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R32 |
| 1 | 360 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R15 |
| 1 | 47p (optional) | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C3 |
| 1 | ADS131M02IPWR | Footprints:TSSOP20_PW_TEX | U6 |
| 1 | BPW34-SMD | OptoDevice:Osram_BPW34S-SMD | D4 |
| 1 | BSS84 | Package_TO_SOT_SMD:SOT-23 | Q6 |
| 1 | FerriteBead | Inductor_SMD:L_0603_1608Metric_Pad1.05x0.95mm_HandSolder | FB1 |
| 1 | ISO6742 | Package_SO:SOIC-16W_7.5x10.3mm_P1.27mm | U4 |
| 1 | LM317_SOT-223 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U3 |
| 1 | LOGO | LOGO | G*** |
| 1 | MCP2221AxSL | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U5 |
| 1 | MCP_RX | TestPoint:TestPoint_Pad_D2.5mm | TP1 |
| 1 | MCP_TX | TestPoint:TestPoint_Pad_D2.5mm | TP2 |
| 1 | TEA 1-0505 | Converter_DCDC:Converter_DCDC_TRACO_TEA1-xxxx_THT | U8 |
| 1 | TLV172IDCK | Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.514x3.2mm | U9 |
| 1 | TestPoint | TestPoint:TestPoint_Pad_D2.5mm | TP17 |
| 1 | USB_B_Micro | Connector_USB:USB_Micro-B_Amphenol_10103594-0001LF_Horizontal | J1 |
| 1 | USB_C_Receptacle_USB2.0_14P | Connector_USB:USB_C_Receptacle_G-Switch_GT-USB-7010ASV | J2 |
| 1 | XIAO-ESP32-C3-DIP | Xiao:XIAO-ESP32-C3-DIP-SMD | U1 |
| 1 | XO32 | Crystal:Crystal_SMD_7050-4Pin_7.0x5.0mm | Y1 |
Questions
How big is the Usb instrument PCB?
It measures 100 × 100 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Usb instrument use?
74 parts, built around the LM321, TLV172IDCK, ISO6742 and BS170. 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 instrument KiCad files?
From the FynnK/Reflectometer repository on GitHub, at the commit this page was made from: the board is kicad/usb-instrument/usb-instrument.kicad_pcb and its schematic kicad/usb-instrument/input_stage.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Usb instrument design in my own project?
Its repository states no licence, so its author keeps all rights: ask FynnK before reusing the design.
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