# 52mm Biomedical BLE Smartwatch ## Description Professional-grade ultra-low-power 52 mm circular BLE smartwatch PCB with biomedical sensing, AMOLED display, USB-C charging, and 6-layer RF/mixed-signal layout constraints. ## Project Details - **Owner:** 12eda - **Created:** 6/19/2026 - **Last Updated:** 6/20/2026 - **Visibility:** Public - **Power Requirements:** Li-ion - **Connectivity:** Bluetooth LE - **Implementation Details:** 52mm circular 6-layer mixed-signal RF biomedical PCB - **Human Interface:** AMOLED - **Domain:** Wearable ## Key Components ### AE1 — [2450AT42E010BE](https://www.flux.ai/vasy_skral/2450at42e010be~g4d.md) - Manufacturer Name: JOHANSON TECHNOLOGY - Role: 2.4GHz antenna - Datasheet URL: https://www.johansontechnology.com/datasheets/2450AT42E010B/2450AT42E010B.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 2450AT42E010BE - Symbol Style: Parametric **Pins:** - FEEDING_POINT [pin 1] - GND_1 [pin 3] - GND_2 [pin 4] - NC [pin 2] ### D1 — [TPD4E02B04DQA](https://www.flux.ai/kicad-part-library/tpd4e02b04dqa~id.md) - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: http://www.ti.com/lit/ds/symlink/tpd4e02b04.pdf - Manufacturer Part Number: TPD4E02B04DQA - Package or Case Code: USON-10_2.5x1.0mm_P0.5mm - Role: Protection **Pins:** - G [pin 3] - G [pin 8] - IO1 [pin 1] - IO2 [pin 2] - IO3 [pin 4] - IO4 [pin 5] - NC [pin 10] - NC [pin 7] - NC [pin 9] - NC [pin 6] ### J1 — [USB4520-03-0-A](https://www.flux.ai/adrian95/usb4520-03-0-a~ufd.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: USB-C input - Manufacturer Part Number: USB4520-03-0-A - Manufacturer Name: GCT - Datasheet URL: https://gct.co/files/specs/usb4520-spec.pdf - Part Type: Connector - Symbol Style: parametric-v1 **Pins:** - CC1 [pin A5] - CC2 [pin B5] - DN1 [pin A7] - DN2 [pin B7] - DP1 [pin A6] - DP2 [pin B6] - GND_A [pin A1] - GND_A [pin B12] - GND_B [pin B1] - GND_B [pin A12] - MH1 [pin S1] - MH2 [pin S4] - MH3 [pin S3] - MH4 [pin S2] - SBU1 [pin A8] - SBU2 [pin B8] - VBUS_A [pin A4] - VBUS_A [pin B9] - VBUS_B [pin B4] - VBUS_B [pin A9] ### J2 — [505110-2491](https://www.flux.ai/vasyl/505110-2491~9sf.md) - Manufacturer Part Number: FINAL_AMOLED_TOUCH_24P_0.4MM_FPC_PINOUT - Connector Pitch: 0.4mm - Manufacturer Name: Molex - Part Type: Connector - Connector Positions: 24 - Role: 24-pin AMOLED + Touch FPC connector placeholder - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: FPC-24P-0.4MM-PLACEHOLDER - Role Details: Final user-approved 24-pin AMOLED+Touch+Power pinout implemented. Electrical pin map: 1 GND, 2 GND, 3 IOVCC=3V3, 4 VBAT/VCI=VBAT, 5 QSPI_CLK, 6 QSPI_CS, 7 QSPI_D0, 8 QSPI_D1, 9 QSPI_D2, 10 QSPI_D3, 11 RESET, 12 TE, 13 BL_EN, 14 BL_PWM, 15 TP_SCL=I2C1_SCL, 16 TP_SDA=I2C1_SDA, 17 TP_INT, 18 TP_RST, 19 TP_VCC=3V3, 20-22 NC, 23 GND, 24 GND, shields to GND. Current library footprint remains 24-pin 0.5mm FPC placeholder; replace mechanical footprint with exact 24-pin 0.4mm FPC before manufacturing. - Allow Substitutes: No - Datasheet URL: https://www.molex.com/pdm_docs/ps/PS-505110-001.pdf **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] - 17 [pin 17] - 18 [pin 18] - 19 [pin 19] - 2 [pin 2] - 20 [pin 20] - 21 [pin 21] - 22 [pin 22] - 23 [pin 23] - 24 [pin 24] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] - SHIELD [pin S1] - SHIELD__1 [pin S2] ### J3 — [Connector 01x06](https://www.flux.ai/jharwinbarrozo/connector-01x06~yh.md) - Part Type: Connector - Role: Li-ion battery connector **Pins:** - Pin_1 [pin 1] - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] - Pin_5 [pin 5] - Pin_6 [pin 6] ### RT1 — [NTCSC0402E3103FLFT](https://www.flux.ai/adrian95/ntcsc0402e3103flft~i0t.md) - Part Type: Thermistor - Datasheet URL: https://www.vishay.com/docs/29238/ntcsc0402e3t.pdf - Manufacturer Name: Vishay Dale - Manufacturer Part Number: NTCSC0402E3103FLFT - Role: Sensing (Shunt) - Resistance: 10kΩ - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - ~ [pin 2] - ~ [pin 1] ### U1 — [QFN50P800X800X100-57V5N](https://www.flux.ai/ipc-7351-packages/qfn50p800x800x100-57v5n~or.md) - Manufacturer Name: Nordic Semiconductor - Role Details: Main BLE MCU placeholder. User provided nRF54LM20A-QFN52 pin image: RF ANT dedicated pad is U1 pin34 and is now the only MCU-side RF feed into L3/matching network/AE1. Display QSPI uses P2.01/pin1 CLK, P2.05/pin5 CS, P2.02/pin2 D0, P2.04/pin4 D1, P2.03/pin3 D2, P2.00/pin52 D3 through R11-R16. USB uses U1 pins 10/11 per existing design. Exact Nordic symbol/land pattern is still required before manufacturing. - Allow Substitutes: No - Role: Main BLE MCU placeholder; exact library part unavailable - Package or Case Code: 52-QFN - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Manufacturer Part Number: nRF54LM20A-QFN52 **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] - 17 [pin 17] - 18 [pin 18] - 19 [pin 19] - 2 [pin 2] - 20 [pin 20] - 21 [pin 21] - 22 [pin 22] - 23 [pin 23] - 24 [pin 24] - 25 [pin 25] - 26 [pin 26] - 27 [pin 27] - 28 [pin 28] - 29 [pin 29] - 3 [pin 3] - 30 [pin 30] - 31 [pin 31] - 32 [pin 32] - 33 [pin 33] - 34 [pin 34] - 35 [pin 35] - 36 [pin 36] - 37 [pin 37] - 38 [pin 38] - 39 [pin 39] - 4 [pin 4] - 40 [pin 40] - 41 [pin 41] - 42 [pin 42] - 43 [pin 43] - 44 [pin 44] - 45 [pin 45] - 46 [pin 46] - 47 [pin 47] - 48 [pin 48] - 49 [pin 49] - 5 [pin 5] - 50 [pin 50] - 51 [pin 51] - 52 [pin 52] - 53 [pin 53] - 54 [pin 54] - 55 [pin 55] - 56 [pin 56] - 57 [pin 57] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] ### U2 — [NPM1300-QEAA-R7](https://www.flux.ai/adrian95/npm1300-qeaa-r7~zb.md) - Role: Battery charger and PMIC - Manufacturer Name: Nordic Semiconductor - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: NPM1300-QEAA-R7 - Package or Case Code: QFN50P500X500X90-33N - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6443/NPM1300-QEAA-R7.pdf - Part Type: Integrated Circuit **Pins:** - AVSS [pin 33] - CC1 [pin 23] - CC2 [pin 24] - GPIO0 [pin 7] - GPIO1 [pin 8] - GPIO2 [pin 9] - GPIO3 [pin 10] - GPIO4 [pin 11] - LED0 [pin 25] - LED1 [pin 26] - LED2 [pin 27] - LSIN1/VINLDO1 [pin 28] - LSIN2/VINLDO2 [pin 30] - LSOUT1/VOUTLDO1 [pin 29] - LSOUT2/VOUTLDO2 [pin 31] - NTC [pin 18] - PVDD [pin 4] - PVSS1 [pin 2] - PVSS2 [pin 6] - SCL [pin 14] - SDA [pin 13] - SHPHLD [pin 15] - SW1 [pin 3] - SW2 [pin 5] - VBAT [pin 19] - VBUS [pin 21] - VBUSOUT [pin 22] - VDDIO [pin 12] - VOUT1 [pin 1] - VOUT2 [pin 32] - VSET1 [pin 17] - VSET2 [pin 16] - VSYS [pin 20] ### U3 — [BME690](https://www.flux.ai/adrian95/bme690.md) - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6476/Bosch%20SensortecBME690_Product%20Flyer1.pdf - Role: Environmental sensor - Manufacturer Name: BOSCH - Part Type: Sensors - Symbol Style: parametric-v1 - Manufacturer Part Number: BME690 - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - CSB [pin 2] - GND_1 [pin 1] - GND_2 [pin 7] - SCK [pin 4] - SDI [pin 3] - SDO [pin 5] - VDD [pin 8] - VDDIO [pin 6] ### U4 — [MAXM86161EFD+](https://www.flux.ai/lcsc/maxm86161efdplus~wz8a.md) - Role: PPG optical sensor - Manufacturer Name: MAXIM(美信) - LCSC Part Number: C1530834 - Manufacturer Part Number: MAXM86161EFD+ - Package or Case Code: OLGA-14_L4.3-W2.9-P0.60-TL - JLCPCB Part Class: Extended Part **Pins:** - GND_ANA [pin 11] - GND_DIG [pin 10] - GPIO [pin 13] - INTB [pin 14] - LDO_EN [pin 3] - N.C. [pin 7] - N.C. [pin 6] - N.C. [pin 8] - PGND [pin 9] - SCL [pin 2] - SDA [pin 1] - VLDO [pin 4] - VLED [pin 5] - VREF [pin 12] ### U5 — [QFN50P500X500X80-33W5N](https://www.flux.ai/ipc-7351-packages/qfn50p500x500x80-33w5n~sy.md) - Role: QSPI NAND flash placeholder - License: https://creativecommons.org/licenses/by/4.0/ - Allow Substitutes: No - Role Details: QSPI NAND placeholder. Final package, pinout, supply voltage, IO voltage, and QSPI timing must be validated against Winbond W25N08LV datasheet before layout release. - Manufacturer Part Number: W25N08LV - Part Type: Integrated Circuit - Package or Case Code: QFN50P500X500X80-33W5N - Manufacturer Name: Winbond **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] - 17 [pin 17] - 18 [pin 18] - 19 [pin 19] - 2 [pin 2] - 20 [pin 20] - 21 [pin 21] - 22 [pin 22] - 23 [pin 23] - 24 [pin 24] - 25 [pin 25] - 26 [pin 26] - 27 [pin 27] - 28 [pin 28] - 29 [pin 29] - 3 [pin 3] - 30 [pin 30] - 31 [pin 31] - 32 [pin 32] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] - EP [pin 33] ### U6 — [BNO086](https://www.flux.ai/adrian95/bno086~4k7.md) - Role: 9-axis IMU - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6531/BNO080_085_Datasheet-3196201.pdf - Manufacturer Name: CEVA Technologies, Inc. - Part Type: Sensor - Manufacturer Part Number: BNO086 **Pins:** - BOOTN [pin 4] - CAP [pin 9] - CLKSEL0 [pin 10] - ENV_SCL [pin 15] - ENV_SDA [pin 16] - GND_1 [pin 2] - GND_2 [pin 25] - H_CSN [pin 18] - H_INTN [pin 14] - H_SCL/SCK/RX [pin 19] - H_SDA/H_MISO/TX [pin 20] - NRST [pin 11] - PS0/WAKE [pin 6] - PS1 [pin 5] - RESV_NC_1 [pin 1] - RESV_NC_2 [pin 7] - RESV_NC_3 [pin 8] - RESV_NC_4 [pin 12] - RESV_NC_5 [pin 13] - RESV_NC_6 [pin 21] - RESV_NC_7 [pin 22] - RESV_NC_8 [pin 23] - RESV_NC_9 [pin 24] - SA0/H_MOSI [pin 17] - VDD [pin 3] - VDDIO [pin 28] - XIN32 [pin 27] - XOUT32/CLKSEL1 [pin 26] ### U7 — [SYP10-A6106](https://www.flux.ai/lcsc/syp10-a6106~3hfj.md) - JLCPCB Part Class: Extended Part - Role: IR skin temperature sensor; GD60914AA I2C TO-39 placeholder - Operating Voltage: 2.4–3.6V - Allow Substitutes: No - Package or Case Code: TO-39-4 - Manufacturer Name: GooDeTek - Connectivity: I2C1_SDA/I2C1_SCL, 3V3, GND - Part Type: Temperature Sensors - Role Details: GD60914AA I2C confirmed by user. Placeholder library pin mapping: U7 TP+::1 = physical Pin1 GND; U7 NTC+::2 = physical Pin2 VDD; U7 TP-::3 = physical Pin3 SDA; U7 GND::4 = physical Pin4 SCL. User provided GD60914A/B mechanical: can OD about 9.12mm, body height about 4.10mm, lead length about 13.8mm, pin circle details must be verified from original drawing. I2C address 0x18; supply 3V3; use 4.7k pullups and local 0.1uF. Final TO-39 pad geometry/order must be verified before manufacturing. - Current: 2.1mA - LCSC Part Number: C2982913 - Manufacturer Part Number: GD60914AA-I2C **Pins:** - GND [pin 4] - NTC+ [pin 2] - TP- [pin 3] - TP+ [pin 1] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/12eda/52mm-biomedical-ble-smartwatch~9h](https://www.flux.ai/12eda/52mm-biomedical-ble-smartwatch~9h).* --- *Generated from [https://www.flux.ai/12eda/52mm-biomedical-ble-smartwatch~9h](https://www.flux.ai/12eda/52mm-biomedical-ble-smartwatch~9h)*