4 layers135.8 × 149.3 mm
TapBadgeV2
Xasin/TapBadgeV2
The second, far more ambitious version of the TapBadge wearable
110 parts6GPL-3.0
4 layers17.8 × 21.4 mm
Epsilon PCB
yassin-v2/EpsilonA very compact development board integrating the RP2354A MCU, named Epsilon.
- Size
- 17.8 × 21.4 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 41
- Nets
- 57
- Pads
- 188
- Tracks, vias
- 553, 87
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 7 Jun 2026
- Updated
- 7 Sep 2026
Overview
Epsilon PCB is an open-source printed circuit board by yassin-v2, from the yassin-v2/Epsilon repository on GitHub, published under the Apache-2.0 licence. It is a 4-layer board of 17.8 × 21.4 mm with 41 parts on 57 nets, routed with 553 tracks and 87 vias.
It is built around the RP2354A and TPSM828214SILR. Its parts include 22 capacitors, 8 resistors, 3 connectors, 2 ICs and 2 diodes. It belongs with the microcontroller boards boards and the RP2350 boards of this library.
Main components
2
RP2354A
QFN-60(7x7)150MHz 32 Bit ARM Cortex-M33 Built-in+External Power-on reset (POR)、Undervoltage detection (BOR/LVD/LVR/LVI)、Watchdog reset、Built-in general-purpose timer、Integrated LDO、Calendar function、True random number generator (TRNG)、Hardware ECC check、Independent watchdog (IWDG) QFN-60(7x7) Microcontrollers (MCU/MPU/SOC) ROHSRaspberry PiMicrocontrollers (MCU/MPU/SOC)
TPSM828214SILR
TFDFN-10(2x2.5)-40℃~+125℃@(TJ) 1 1A 2.4V~5.5V 4MHz Buck Buck Built-in Yes TFDFN-10(2x2.5) DC-DC Converters ROHSTexas InstrumentsDC-DC Converters
README
README.mdEpsilon
A very compact, 4-layer devboard integrating the RP2354A MCU, named Epsilon.
Features
- RP2354A MCU - 32bit dual core ARM Cortex-M33 MCU, with RISC-V cores and 2Mb of internal flash memory.
- Very compact, XIAO SEEED inspired formfactor.
- 4 ADC and 7 digital GPIO pins.
- 5V and 3.3V output power pins.
- Power indicator LED and addressable LED.
- USB C - for programming and power.
PCB Design
Find the PCB files here.
The PCB is 4 layers with dimensions 21mm × 17.8mm.
| Top Layer | Inner Plane 1; GND |
|---|---|
 |  |
| Inner Plane 2; Power | Bottom Layer |
|---|---|
 |  |
Schematic Design
Find the Schematic files here, or as a PDF, here.
Pinout
Parts
41| Qty | Value | Footprint | References |
|---|---|---|---|
| 11 | 100nF | Capacitor_SMD:C_0402_1005Metric | C8, C11, C12, C13, C14, C15, C16, C17, C18, C20, C21 |
| 5 | 10uF | Capacitor_SMD:C_0402_1005Metric | C1, C2, C5, C19, C22 |
| 4 | 4.7uF | Capacitor_SMD:C_0402_1005Metric | C6, C7, C9, C10 |
| 3 | 33 | Resistor_SMD:R_0402_1005Metric | R2, R3, R6 |
| 2 | 15pF | Capacitor_SMD:C_0402_1005Metric | C3, C4 |
| 2 | 470 | Resistor_SMD:R_0402_1005Metric | R4, R5 |
| 2 | 5.1K | Resistor_SMD:R_0402_1005Metric | R7, R8 |
| 2 | Conn_01x07 | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Vertical | J2, J3 |
| 2 | LED | LED_SMD:LED_0402_1005Metric | D2, D3 |
| 2 | TestPoint | TestPoint:TestPoint_Pad_1.0x1.0mm | TP1, TP2 |
| 1 | 12MHz | Crystal:Crystal_SMD_Abracon_ABM8G-4Pin_3.2x2.5mm | Y1 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 3.3uH | LDO:IND-SMD_L2.0-W1.6_AOTA-B201610S3R3-101-T | L1 |
| 1 | RP2354A | Package_DFN_QFN:QFN-60-1EP_7x7mm_P0.4mm_EP3.4x3.4mm | U1 |
| 1 | TPSM828214SILR | LDO:USIP-10_L2.5-W2.0-P0.50-BL | U2 |
| 1 | USB_C_Receptacle_USB2.0_16P | Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
Questions
How big is the Epsilon PCB PCB?
It measures 17.8 × 21.4 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Epsilon PCB use?
41 parts, built around the RP2354A and TPSM828214SILR. 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 Epsilon PCB KiCad files?
From the yassin-v2/Epsilon repository on GitHub, at the commit this page was made from: the board is PCB/Epsilon PCB.kicad_pcb and its schematic PCB/Epsilon Schematic.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Epsilon PCB 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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