# EMG PCB ## Description 8-Channel Wearable BLE5 Brain–Computer Interface with 24-bit Biopotential AFE and Cross-Platform SDKs ## Project Details - **Owner:** alikay - **Created:** 1/23/2026 - **Last Updated:** 3/26/2026 - **Visibility:** Public - **BLE MCU Selection:** nRF52840 - **Electrode Connector:** 10-pin board-mount connector for 8 channels, reference, and bias/DRL supporting wet and dry electrodes - **System Architecture:** ```mermaid flowchart TD Power["Power Subsystem"] AFE["Biopotential AFE/ADC"] MCU["BLE MCU/SoC"] Con["Electrode Connector"] LED["Status LEDs"] Power --> AFE Power --> MCU MCU --> AFE Con --> AFE MCU --> LED AFE --> LED ``` ## Key Components ### D1 — [PESD3V3L5UY](https://www.flux.ai/kicad-part-library/pesd3v3l5uy.md) - Max Reverse Voltage: 5.5V - Manufacturer Part Number: PESD3V3L5UY - Datasheet URL: https://assets.nexperia.com/documents/data-sheet/PESDXL5UF_V_Y.pdf - Manufacturer Name: Texas Instruments Inc. - Role: Protection - Role Details: Input ESD protection for AFE channels - Package or Case Code: SOT-363_SC-70-6 **Pins:** - A [pin 2] - K1 [pin 1] - K2 [pin 3] - K3 [pin 4] - K4 [pin 5] - K5 [pin 6] ### D2 — [PESD3V3L5UY](https://www.flux.ai/kicad-part-library/pesd3v3l5uy.md) - Package or Case Code: SOT-363_SC-70-6 - Role: Protection - Max Reverse Voltage: 5.5V - Datasheet URL: https://assets.nexperia.com/documents/data-sheet/PESDXL5UF_V_Y.pdf - Manufacturer Name: Texas Instruments Inc. - Manufacturer Part Number: PESD3V3L5UY - Role Details: Input ESD protection for AFE channels **Pins:** - A [pin 2] - K1 [pin 1] - K2 [pin 3] - K3 [pin 4] - K4 [pin 5] - K5 [pin 6] ### J1 — [929850-01-10-RA](https://www.flux.ai/adrian95/929850-01-10-ra.md) - Package: 929850-01-10-RA - Connector Positions: 10 - Connector Type: Headers and Wire Housings - Connector Rows: 2 - Role: Connector - Datasheet URL: https://multimedia.3m.com/mws/media/22500O/3mtm-boardmount-skt-100-100x-100strt-sldr-tails-ts0815.pdf - Manufacturer Name: Molex - Part Type: Connector - Role Details: Electrode connector for 8 channels, reference, and bias/DRL - Mount: Through Hole - Manufacturer Part Number: 929850-01-10-RA **Pins:** - Pin_1 - Pin_10 - Pin_2 - Pin_3 - Pin_4 - Pin_5 - Pin_6 - Pin_7 - Pin_8 - Pin_9 ### J2 — [USB-C 2.0 Receptacle](https://www.flux.ai/corynrobinson/usb-c-20-receptacle.md) - Manufacturer Part Number: USB4105-GF-A - Datasheet URL: https://gct.co/files/drawings/usb4105.pdf - Role: Connector - Package: USB4105-GF-A - Connector Type: USB Connectors - Mount: Surface Mount - Bus Type: USB 2.0 - Connectivity: USB - Manufacturer Name: GCT - Purchase Url: https://www.digikey.com/en/products/detail/gct/USB4105-GF-A/11198441 - Connector Gender: Receptacle - Role Details: USB-C port for charging and data - Part Type: USB C **Pins:** - CC1 [pin 6] - CC2 [pin 12] - D- [pin 7] - D- [pin 9] - D+ [pin 10] - D+ [pin 8] - GND [pin 1] - GND [pin 16] - GND [pin 15] - GND [pin 2] - SBU1 [pin 11] - SBU2 [pin 5] - VBUS [pin 3] - VBUS [pin 14] - VBUS [pin 4] - VBUS [pin 13] ### J3 — [2x5 Pin Shrouded Header](https://www.flux.ai/rex-flux/2x5-pin-shrouded-header.md) - Datasheet URL: https://www.we-online.com/catalog/datasheet/61201021621.pdf - Package: 61201021621 - Mount: Through Hole - Manufacturer Part Number: 61201021621 - Manufacturer Name: Würth - Part Type: Connector - Connector Rows: 2 - Connector Type: Headers and Wire Housings - Role Details: Debug/programming header for MCU SWD and UART - Role: Connector - Connector Positions: 10 **Pins:** - P1 [pin 1] - P10 [pin 10] - P2 [pin 2] - P3 [pin 3] - P4 [pin 4] - P5 [pin 5] - P6 [pin 6] - P7 [pin 8] - P7 [pin 7] - P9 [pin 9] ### J4 — [S2B-PH-SM4-TB(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-sm4-tblfsn.md) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: JST Sales America Inc. - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Manufacturer Part Number: S2B-PH-SM4-TB(LF)(SN) - Role Details: 2-pin JST-PH battery connector; pin1=BAT+, pin2=GND. - Role: Connector - Package: JST-PH-2 SMD RA **Pins:** - P1 [pin 1] - P2 [pin 2] ### LDO1 — [TLV70033DDCT](https://www.flux.ai/lcsc/tlv70033ddct.md) - Role: Power Conversion - Package or Case Code: SOT-23-5 - Manufacturer Name: TI(德州仪器) - Part Type: Linear Regulator - Package: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR - Footprint: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR - Manufacturer Part Number: TLV70033DDCT - LCSC Part Number: C2877582 - Role Details: Low-noise 3.3V regulator for MCU and AFE power rails - JLCPCB Part Class: Extended Part **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - N/C [pin 4] - OUT [pin 5] ### LDO2 — [TLV70033DDCT](https://www.flux.ai/lcsc/tlv70033ddct.md) - Part Type: Linear Voltage Regulators (LDO) - Manufacturer Name: TI(德州仪器) - Package: SOT-23-5 - Package or Case Code: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR - Role Details: Analog 3.3V LDO dedicated to ADS1299 AVDD (3V3_A). - Role: Power Conversion - LCSC Part Number: C2877582 - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TLV70033DDCT **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - N/C [pin 4] - OUT [pin 5] ### PROG — [61300621121](https://www.flux.ai/adrian95/61300621121.md) - Part Type: Connector - Manufacturer Name: Wurth Elektronik - Datasheet URL: https://www.we-online.com/katalog/datasheet/6130xx21121.pdf - Package or Case Code: HDRV6W64P254_2X3_762X508X889P - Role Details: SWD 2x3 programming header for nRF52840 (SWDIO, SWDCLK, 3V3, GND). - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 61300621121 - Role: Connector - Package: 2x3 2.54mm THT **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] ### U1 — [TXB0108DQSR](https://www.flux.ai/adrian95/txb0108dqsr.md) - Package or Case Code: 20-USON - Role Details: Bidirectional level translation between MCU and AFE digital interfaces - Manufacturer Name: Texas Instruments - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Datasheet URL: https://www.ti.com/lit/ds/symlink/txb0108.pdf - Role: Logic-level Shifting - Footprint: USON-20_2x4mm_P0.4mm - Manufacturer Part Number: TXB0108DQSR **Pins:** - A1 [pin 1] - A2 [pin 2] - A3 [pin 3] - A4 [pin 4] - A5 [pin 7] - A6 [pin 8] - A7 [pin 9] - A8 [pin 10] - B1 [pin 20] - B2 [pin 19] - B3 [pin 18] - B4 [pin 17] - B5 [pin 14] - B6 [pin 13] - B7 [pin 12] - B8 [pin 11] - GND [pin 15] - OE [pin 6] - VCCA [pin 5] - VCCB [pin 16] ### U2 — [ADS1299IPAGR](https://www.flux.ai/adrian95/ads1299ipagr.md) - Role Details: Main 8-channel 24-bit biopotential AFE/ADC for EEG/EMG; 250 SPS per channel; SPI interface; requires bias/ref and input protection - Manufacturer Name: Texas Instruments - Datasheet URL: https://www.ti.com/lit/ds/symlink/ads1299.pdf - Part Type: Integrated Circuit - Footprint: TQFP-64_10x10mm_P0.50 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: ADS1299IPAGR - Package or Case Code: 64-TQFP - Role: Data Conversion **Pins:** - ~CS [pin 39] - ~DRDY [pin 47] - ~PWDN [pin 35] - ~RESET [pin 36] - AVDD_1 [pin 19] - AVDD_2 [pin 22] - AVDD_3 [pin 23] - AVDD_4 [pin 56] - AVDD_5 [pin 59] - AVDD1 [pin 54] - AVSS_1 [pin 20] - AVSS_2 [pin 21] - AVSS_3 [pin 32] - AVSS_4 [pin 57] - AVSS_5 [pin 58] - AVSS1 [pin 53] - BIASIN [pin 62] - BIASINV [pin 61] - BIASOUT [pin 63] - BIASREF [pin 60] - CLK [pin 37] - CLKSEL [pin 52] - DAISY_IN [pin 41] - DGND_1 [pin 33] - DGND_2 [pin 49] - DGND_3 [pin 51] - DIN [pin 34] - DOUT [pin 43] - DVDD_1 [pin 48] - DVDD_2 [pin 50] - GPIO1 [pin 42] - GPIO2 [pin 44] - GPIO3 [pin 45] - GPIO4 [pin 46] - IN1N [pin 15] - IN1P [pin 16] - IN2N [pin 13] - IN2P [pin 14] - IN3N [pin 11] - IN3P [pin 12] - IN4N [pin 9] - IN4P [pin 10] - IN5N [pin 7] - IN5P [pin 8] - IN6N [pin 5] - IN6P [pin 6] - IN7N [pin 3] - IN7P [pin 4] - IN8N [pin 1] - IN8P [pin 2] - NC_1 [pin 27] - NC_2 [pin 29] - RESERVED [pin 64] - RESV1 [pin 31] - SCLK [pin 40] - SRB1 [pin 17] - SRB2 [pin 18] - START [pin 38] - VCAP1 [pin 28] - VCAP2 [pin 30] - VCAP3 [pin 55] - VCAP4 [pin 26] - VREFN [pin 25] - VREFP [pin 24] ### U3 — [nRF52840](https://www.flux.ai/vasyl/nrf52840.md) - Part Type: Microcontroller - Datasheet URL: https://infocenter.nordicsemi.com/pdf/nRF52840_PS_v1.5.pdf - Role: Microcontroller - Manufacturer Name: Nordic Semiconductor ASA - Manufacturer Part Number: NRF52840-QIAA-R - Package: AQFN-73_L7.0-W7.0-P0.50-BL-EP4.8 - Package or Case Code: 73-VFQFN - Role Details: BLE 5 SoC for biopotential data streaming - Footprint: AQFN-73_L7.0-W7.0-P0.50-BL-EP4.8 **Pins:** - AIN0/P0.02 [pin A12] - AIN1/P0.03 [pin B13] - AIN2/P0.04 [pin J1] - AIN3/P0.05 [pin K2] - AIN4/P0.28 [pin B11] - AIN5/P0.29 [pin A10] - AIN6/P0.30 [pin B9] - AIN7/P0.31 [pin A8] - ANT [pin H23] - D- [pin AD4] - D+ [pin AD6] - DCC [pin B3] - DCCH [pin AB2] - DEC1 [pin C1] - DEC2 [pin A18] - DEC3 [pin D23] - DEC4 [pin B5] - DEC5 [pin N24] - DEC6 [pin E24] - DECUSB [pin AC5] - NFC1/P0.09 [pin L24] - NFC2/P0.10 [pin J24] - P0.06 [pin L1] - P0.08 [pin N1] - P0.13 [pin AD8] - P0.14 [pin AC9] - P0.15 [pin AD10] - P0.16 [pin AC11] - P0.17 [pin AD12] - P0.18/~RESET [pin AC13] - P0.19 [pin AC15] - P0.20 [pin AD16] - P0.21 [pin AC17] - P0.22 [pin AD18] - P0.23 [pin AC19] - P0.24 [pin AD20] - P0.25 [pin AC21] - P0.26 [pin G1] - P0.27 [pin H2] - P1.01 [pin Y23] - P1.02 [pin W24] - P1.03 [pin V23] - P1.04 [pin U24] - P1.05 [pin T23] - P1.06 [pin R24] - P1.07 [pin P23] - P1.08 [pin P2] - P1.10 [pin A20] - P1.11 [pin B19] - P1.12 [pin B17] - P1.13 [pin A16] - P1.14 [pin B15] - P1.15 [pin A14] - SWDCLK [pin AA24] - SWDIO [pin AC24] - TRACECLK/P0.07 [pin M2] - TRACEDATA0/P1.00 [pin AD22] - TRACEDATA1/P0.12 [pin U1] - TRACEDATA2/P0.11 [pin T2] - TRACEDATA3/P1.09 [pin R1] - VBUS [pin AD2] - VDD [pin B1] - VDD [pin AD14] - VDD [pin A22] - VDD [pin W1] - VDD [pin AD23] - VDDH [pin Y2] - VSS [pin EP] - VSS [pin B7] - VSS_PA [pin F23] - XC1 [pin B24] - XC2 [pin A23] - XL1/P0.00 [pin D2] - XL2/P0.01 [pin F2] ### U4 — [BQ25895MRTWR](https://www.flux.ai/lcsc/bq25895mrtwr.md) - LCSC Part Number: C485917 - JLCPCB Part Class: Extended Part - Manufacturer Name: TI(德州仪器) - Role: Power Source - Role Details: USB-C Li-ion charger IC; integrated power-path management and CC negotiation up to 2 A - Package or Case Code: 24-WQFN - Manufacturer Part Number: BQ25895MRTWR - Footprint: WQFN-24_L4.0-W4.0-P0.50-TL-EP2.7 **Pins:** - ~{CE} [pin 9] - ~{QON} [pin 12] - BAT [pin 13] - BAT [pin 14] - BTST [pin 21] - D– [pin 3] - D+ [pin 2] - DSEL [pin 24] - EP [pin 18] - ILIM [pin 10] - INT [pin 7] - OTG [pin 8] - PGND [pin 17] - PGND [pin 18] - PMID [pin 23] - REGN [pin 22] - SCL [pin 5] - SDA [pin 6] - STAT [pin 4] - SW [pin 19] - SW [pin 20] - SYS [pin 15] - SYS [pin 16] - TS [pin 11] - VBUS [pin 1] ### Y1 — [NX2016SA-32MHZ-STD-CZS-5](https://www.flux.ai/lcsc/nx2016sa-32mhz-std-czs-5.md) - Role: Oscillator - Package or Case Code: OSC-SMD - Manufacturer Name: NDK - LCSC Part Number: C843260 - Package: OSC-SMD_4P-L2.0-W1.6-BL - Manufacturer Part Number: NX2016SA-32MHZ-STD-CZS-5 - JLCPCB Part Class: Extended Part - Part Type: Oscillator - Role Details: 32 MHz external crystal for MCU - Footprint: OSC-SMD_4P-L2.0-W1.6-BL **Pins:** - 1 [pin 1] - 3 [pin 3] - GND [pin 4] - GND [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/alikay/emg-pcb](https://www.flux.ai/alikay/emg-pcb).* --- *Generated from [https://www.flux.ai/alikay/emg-pcb](https://www.flux.ai/alikay/emg-pcb)*