# 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:** ddsd - **Created:** 6/19/2026 - **Last Updated:** 6/19/2026 - **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 - **Stars:** 1 - **Copies:** 1 ## Key Components ### AE1 — [2450AT42E010BE](https://www.flux.ai/vasy_skral/2450at42e010be~g4d.md) - Role: 2.4GHz antenna - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 2450AT42E010BE - Datasheet URL: https://www.johansontechnology.com/datasheets/2450AT42E010B/2450AT42E010B.pdf - Manufacturer Name: JOHANSON TECHNOLOGY - 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) - Datasheet URL: http://www.ti.com/lit/ds/symlink/tpd4e02b04.pdf - Manufacturer Name: Texas Instruments Inc. - Package or Case Code: USON-10_2.5x1.0mm_P0.5mm - Manufacturer Part Number: TPD4E02B04DQA - 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) - Symbol Style: parametric-v1 - Datasheet URL: https://gct.co/files/specs/usb4520-spec.pdf - Role: USB-C input - Manufacturer Name: GCT - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: USB4520-03-0-A **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 — [Connector 01x06](https://www.flux.ai/jharwinbarrozo/connector-01x06~yh.md) - Role: AMOLED/touch connector placeholder - Part Type: 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] ### 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) - Resistance: 10kΩ - Manufacturer Part Number: NTCSC0402E3103FLFT - Manufacturer Name: Vishay Dale - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.vishay.com/docs/29238/ntcsc0402e3t.pdf - Part Type: Thermistor - Role: Sensing (Shunt) **Pins:** - ~ [pin 2] - ~ [pin 1] ### U1 — [QFN50P800X800X100-57V5N](https://www.flux.ai/ipc-7351-packages/qfn50p800x800x100-57v5n~or.md) - Manufacturer Name: Nordic Semiconductor - Manufacturer Part Number: nRF54LM20A - Package or Case Code: QFN50P800X800X100-57V5N - Part Type: Integrated Circuit - Allow Substitutes: No - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Use as schematic/layout placeholder only. Final symbol pin mapping and recommended package/footprint must be validated against Nordic nRF54LM20A datasheet before manufacturing. Keep within 10–15 mm of AE1 antenna feed; RF path 50 ohm controlled impedance with minimal vias. - Role: Main BLE MCU placeholder; exact library part unavailable **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 Part Number: NPM1300-QEAA-R7 - Manufacturer Name: Nordic Semiconductor - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6443/NPM1300-QEAA-R7.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Package or Case Code: QFN50P500X500X90-33N **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) - Manufacturer Part Number: BME690 - Symbol Style: parametric-v1 - Manufacturer Name: BOSCH - Role: Environmental sensor - Part Type: Sensors - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6476/Bosch%20SensortecBME690_Product%20Flyer1.pdf - 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) - Manufacturer Name: MAXIM(美信) - Manufacturer Part Number: MAXM86161EFD+ - JLCPCB Part Class: Extended Part - Role: PPG optical sensor - LCSC Part Number: C1530834 - Package or Case Code: OLGA-14_L4.3-W2.9-P0.60-TL **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) - Part Type: Integrated Circuit - 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 Name: Winbond - Allow Substitutes: No - Role: QSPI NAND flash placeholder - Manufacturer Part Number: W25N08LV - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: QFN50P500X500X80-33W5N **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) - Manufacturer Part Number: BNO086 - Part Type: Sensor - Role: 9-axis IMU - Manufacturer Name: CEVA Technologies, Inc. - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6531/BNO080_085_Datasheet-3196201.pdf **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 — [QFN50P500X500X80-33W5N](https://www.flux.ai/ipc-7351-packages/qfn50p500x500x80-33w5n~sy.md) - Manufacturer Part Number: GD60914AA - Allow Substitutes: No - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: QFN50P500X500X80-33W5N - Part Type: Integrated Circuit - Manufacturer Name: Winbond - Role Details: Bottom-side optical/FOV sensor placeholder. Final I2C/UART pin mapping, package, optical aperture, and keepout must be validated from GD60914AA datasheet/enclosure stackup before manufacturing. - Role: IR non-contact skin temperature sensor placeholder **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] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/ddsd/52mm-biomedical-ble-smartwatch~3j](https://www.flux.ai/ddsd/52mm-biomedical-ble-smartwatch~3j).* --- *Generated from [https://www.flux.ai/ddsd/52mm-biomedical-ble-smartwatch~3j](https://www.flux.ai/ddsd/52mm-biomedical-ble-smartwatch~3j)*