2 layers38.3 × 15.5 mm
PPG Watch
gavin4d/PPG-Watch
Smart watch with a photoplethysmography analog front end and e-paper display
22 parts
6 layers21 × 36 mm
PPG Watch
gavin4d/PPG-WatchSmart watch with a photoplethysmography analog front end and e-paper display
- Size
- 21 × 36 mm
- Copper layers
- 6
- Thickness
- 0.85 mm
- Parts
- 89
- Nets
- 112
- Pads
- 380
- Tracks, vias
- 976, 182
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 23 Oct 2025
- Updated
- 20 Nov 2025
Overview
PPG Watch is an open-source printed circuit board by gavin4d, from the gavin4d/PPG-Watch repository on GitHub. It is a 6-layer board of 21 × 36 mm with 89 parts on 112 nets, routed with 976 tracks and 182 vias.
It is built around the MCP3561R-E/NC, SFH 7072 and LSM6DSM, with the NJL5821R, SR4W035 and TPS78227DDC among its other parts. Its parts include 30 capacitors, 28 resistors, 10 ICs, 7 transistors and 4 diodes. It belongs with the wearables and lEDs and displays boards and the nRF52 and nRF5x boards of this library.
Main components
11
MCP3561R-E/NC
UQFN-20(3x3)-40℃~+125℃ 1 106.7dB 10LSB 153.6kHz 153.6kHz 15ppm/℃ 1MHz~20MHz、3.3MHz~6.6MHz 2.7V~3.6V 24 Built-in External、Built-in External、Built-in SPI Sigma-Delta Support Yes UQFN-20(3x3) Analog to Digital Converters (ADC) ROHSMicrochip TechnologyAnalog To Digital Converters (ADC)
SFH 7072
DFN-12(3.9x7.5)DFN-12(3.9x7.5) Human Body Sensing Sensor ROHSOSRAM Opto SemiconHuman Body Sensing Sensor
LSM6DSM
LGA-14(2.5x3)-40℃~+85℃ 1.71V~3.6V 4KB Accelerometer Gyroscope SPI、I2C X,Y,Z X,Y,Z ±16g ±2000dps LGA-14(2.5x3) Accelerometers ROHSSTMicroelectronicsAccelerometersNJL5821R
DFN6UncategorisedNisshinbo Micro Devices Inc.
SR4W035
SMD6040-6P-40℃~+140℃ 0.4mm 1.8 100MHz 2.4GHz 3.5dBi 4mm 50Ω 6mm Patch Antenna SMD6040-6P Antennas ROHSAntenovaAntennas
TPS78227DDC
SOT-23-5-40℃~+125℃@(Tj) 1 108uVrms 150mA 2.7V 250mV@(150mA) 40dB@(10Hz) 5.5V 500nA Fixed Over Current Protection、Thermal Shutdown、Enable control Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) RegulatorsTXU0102
UncategorisedTexas Instruments
RE1C002UN-TP
SOT-5231 N-channel 120pF 15pF 20V 20pF 250mΩ@4.5V、300mΩ@2.5V 280mW 750mV 800mA SOT-523 MOSFETs ROHSTECH PUBLICMOSFETs
CTS05S30,L3F
SOD-8821 Independent 150uA@10V 2A 30V 340mV@100mA 500mA SOD-882 Schottky Diodes ROHSToshibaSchottky Diodes
RE1C002ZPTL
SOT-416F-55℃~+150℃ 1 P-Channel 1.2Ω@4.5V 1.4nC@4.5V 115pF 150mW 200mA 20V 300mV SOT-416F MOSFETs ROHSROHM SemiconductorMOSFETs
SI2302CDS
SOT-231 N-channel 2.9A 20V 3.5nC@10V,4.5V 550mW 75mΩ@2.5V 850mV N-Channel SOT-23 MOSFETs ROHSVishay IntertechnologyMOSFETs
Parts
89| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 1u | Capacitor_SMD:C_0402_1005Metric | C6, C7, C9, C10, C12, C13, C16, C22, C23, C25, C26, C32 |
| 11 | R | Resistor_SMD:R_0402_1005Metric | R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 |
| 7 | 0 | Resistor_SMD:R_0402_1005Metric | R21, R24, R25, R26, R27, R28, R29 |
| 6 | C | Capacitor_SMD:C_0402_1005Metric | C15, C17, C18, C19, C20, C21 |
| 5 | RE1C002UN | Package_TO_SOT_SMD:SOT-416 | Q1, Q4, Q5, Q6, Q7 |
| 4 | 4u7 | Capacitor_SMD:C_0603_1608Metric | C1, C2, C4, C5 |
| 3 | 1M | Resistor_SMD:R_0402_1005Metric | R1, R4, R6 |
| 3 | CTS05S30 | Diode_SMD:D_SOD-882 | D1, D2, D3 |
| 2 | 100n | Capacitor_SMD:C_0402_1005Metric | C28, C29 |
| 2 | 1u | Capacitor_SMD:C_0603_1608Metric | C3, C11 |
| 2 | 5k1 | Resistor_SMD:R_0402_1005Metric | R7, R8 |
| 1 | 100p | Capacitor_SMD:C_0402_1005Metric | C30 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R30 |
| 1 | 10u | Inductor_SMD:L_0603_1608Metric | L3 |
| 1 | 15n | Inductor_SMD:L_0402_1005Metric | L4 |
| 1 | 1M5 | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 1p2 | Capacitor_SMD:C_0402_1005Metric | C14 |
| 1 | 1p5 | Capacitor_SMD:C_0402_1005Metric | C8 |
| 1 | 220k | Resistor_SMD:R_0402_1005Metric | R5 |
| 1 | 2R2 | Resistor_SMD:R_0402_1005Metric | R3 |
| 1 | 2k2 | Resistor_SMD:R_0402_1005Metric | R9 |
| 1 | 47n | Capacitor_SMD:C_0402_1005Metric | C31 |
| 1 | 47u | Inductor_SMD:L_Bourns-SRN4018 | L1 |
| 1 | 4n2 | Inductor_SMD:L_0402_1005Metric | L2 |
| 1 | Battery | Library:Battery | BT1 |
| 1 | Conn_01x02_Pin | Connector_PinSocket_1.00mm:PinSocket_1x02_P1.00mm_Vertical | J3 |
| 1 | Conn_ARM_SWD_TagConnect_TC2030-NL | Connector:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical | J2 |
| 1 | GDEH0154D67 | Library:GDEH0154D67 | DIS1 |
| 1 | LSM6DSM | Package_LGA:LGA-14_3x2.5mm_P0.5mm_LayoutBorder3x4y | U1 |
| 1 | MCP23S18x-x-MJ | Package_DFN_QFN:HVQFN-24-1EP_4x4mm_P0.5mm_EP2.6x2.6mm_ThermalVias | U11 |
| 1 | MCP3561R | Package_DFN_QFN:QFN-20-1EP_3x3mm_P0.4mm_EP1.65x1.65mm | U10 |
| 1 | MCP73832-2-OT | Package_TO_SOT_SMD:SOT-23-5 | U3 |
| 1 | NJL5821R | Library:NJL5821R | U8 |
| 1 | OPA2381 | Package_DFN_QFN:DFN-8-1EP_3x3mm_P0.65mm_EP1.55x2.4mm | U4 |
| 1 | RE1C002ZP | Package_TO_SOT_SMD:SOT-416 | Q3 |
| 1 | SFH7072 | Library:SFH7072 | D4 |
| 1 | SI2302CDS | Package_TO_SOT_SMD:SOT-23 | Q2 |
| 1 | SR4W035 | Library:SR4W035_4X6_ANT | U5 |
| 1 | SiT1552 | Library:SiT1552 | Y1 |
| 1 | TPS78227DDC | Package_TO_SOT_SMD:SOT-23-5 | U6 |
| 1 | TXU0102 | Library:X1SON-8_1.05x2mm_P0.5mm | U7 |
| 1 | USB_C_Receptacle_USB2.0_16P | Library:GCT_USB4720-03-A_REVA | J1 |
| 1 | nRF52833_QDxx | Package_DFN_QFN:QFN-40-1EP_5x5mm_P0.4mm_EP3.6x3.6mm | U2 |
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Questions
How big is the PPG Watch PCB?
It measures 21 × 36 mm and has 6 copper layers, 0.85 mm thick.
What parts does the PPG Watch use?
89 parts, built around the MCP3561R-E/NC, SFH 7072, LSM6DSM and NJL5821R. 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 PPG Watch KiCad files?
From the gavin4d/PPG-Watch repository on GitHub, at the commit this page was made from: the board is PCB/PPG-Watch.kicad_pcb and its schematic PCB/PPG-Watch.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PPG Watch design in my own project?
Its repository states no licence, so its author keeps all rights: ask gavin4d before reusing the design.