# Yelling Lime Memory Implanter ## Description Bioimpedance + ECG/PTT node (USB-C protected 5V in, Howland pump, INA128 front end, STM32WB55 BLE, I2C sensors, SWD) ## Project Details - **Owner:** varshars1711 - **Created:** 2/18/2026 - **Last Updated:** 2/18/2026 - **Visibility:** Public - **System Architecture:** flowchart TD subgraph Power [Power] USB[USB-C 5V] --> Prot[Reverse OV UVLO OCP] Prot --> Reg33[3.3V Regulation] end subgraph Electrodes [Electrodes] EConn[Tetrapolar Electrode Connector\nI+ I- V+ V-] end subgraph Injection [Bioimpedance Injection] DAC[MCU DAC/PWM->Filter] --> Howland[Howland Current Pump\nOP07 + Matched R] Howland --> EConn end subgraph Sensing [Analog Sensing] EConn --> INA[Instrumentation Amplifier] INA --> ADC[MCU ADC] ECG[ECG/PTT Front End] --> ADC end subgraph Sensors [Digital Sensors] PPG[MAX30102 PPG] --> I2C[I2C] IMU[IMU] --> I2C SHT[SHT3x Temp/RH] --> I2C end subgraph MCU_RF [MCU and RF] Reg33 --> MCU[STM32WB55 BLE MCU] MCU --> I2C MCU --> BLE[2.4GHz Antenna\nKeepout] MCU --> OptionalWiFi[Optional Wi-Fi Module] end Power --> Injection Power --> Sensing Power --> Sensors Power --> MCU_RF - **Floorplanning Notes:** Partition PCB into 3 zones: (1) Power entry/regulation: J1 USB-C, U2 eFuse, input bulk C9/C10, LDO U3, bulk C7/C8/C11/C12. Keep high di/dt loops tight, place TVS/fuse as needed. (2) Analog: Howland current pump U4 + R3/R4/R5/R6 matched network, electrode connector J2, INA128 U5 + RG resistor R7, guard ring around INA inputs, route V_SENSE_P/V_SENSE_N as tightly-coupled pair with GND guard, keep away from SWD/UART/I2C. Star/quiet analog return to main GND near U5 and keep injection return away from sense return. (3) Digital/RF: U1 STM32WB5MMG, I2C sensors U6/U7/IC1 with pullups R8/R9, ESP1 placeholder. Antenna keepout: no copper/ground pour/components under U1 ANT area and at least 15 mm clearance in front of antenna. Keep RF path short, solid GND reference around RF except keepout. Stitch ground vias at zone boundaries. ## Key Components ### ESP1 — [ESP32-WROOM-32U](https://www.flux.ai/vasy_skral/esp32-wroom-32u.md) - Manufacturer Part Number: ESP32-WROOM-32U - Role: Wireless Module - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf - Package: Module - Manufacturer Name: Espressif Systems - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Module - Role Details: Optional Wi-Fi/BLE module placeholder (not required for base BOM) **Pins:** - <=GND [pin 39_2] - 3V3 [pin 2] - EN [pin 3] - GND [pin 39_3] - GND [pin 39_9] - GND [pin 39_10] - GND [pin 39_19] - GND [pin 39_17] - GND [pin 1] - GND [pin 39_15] - GND [pin 39_11] - GND [pin 39_4] - GND [pin 39_12] - GND [pin 39_1] - GND [pin 15] - GND [pin 39_5] - GND [pin 39_18] - GND [pin 38] - GND [pin 39_7] - GND [pin 39_13] - GND [pin 39_14] - GND [pin 39_21] - GND [pin 39_8] - GND [pin 39_20] - GND [pin 39_16] - GND [pin 39_6] - IO0 [pin 25] - IO12 [pin 14] - IO13 [pin 16] - IO14 [pin 13] - IO15 [pin 23] - IO16 [pin 27] - IO17 [pin 28] - IO18 [pin 30] - IO19 [pin 31] - IO2 [pin 24] - IO21 [pin 33] - IO22 [pin 36] - IO23 [pin 37] - IO25 [pin 10] - IO26 [pin 11] - IO27 [pin 12] - IO32 [pin 8] - IO33 [pin 9] - IO34 [pin 6] - IO35 [pin 7] - IO4 [pin 26] - IO5 [pin 29] - RXD0 [pin 34] - SCK/CLK [pin 20] - SCS/CMD [pin 19] - SDI/SD1 [pin 22] - SDO/SD0 [pin 21] - SENSOR_VN [pin 5] - SENSOR_VP [pin 4] - SHD/SD2 [pin 17] - SWP/SD3 [pin 18] - TXD0 [pin 35] ### IC1 — [SHT31-DIS-B2.5KS](https://www.flux.ai/adrian95/sht31-dis-b2p5ks.md) - Manufacturer Name: Sensirion - Datasheet URL: https://sensirion.com/media/documents/213E6A3B/63A5A569/Datasheet_SHT3x_DIS.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Sensor - Role Details: Temp/RH (SHT3x) on I2C - Role: Sensor - Manufacturer Part Number: SHT31-DIS-B2.5KS - Package: DFN-6/8 2.5x2.5 **Pins:** - ADDR [pin 2] - ALERT [pin 3] - EP [pin 9] - NRESET [pin 6] - R [pin 7] - SCL [pin 4] - SDA [pin 1] - VDD [pin 5] - VSS [pin 8] ### J1 — [USB-C 2.0 Receptacle](https://www.flux.ai/corynrobinson/usb-c-20-receptacle.md) - Role Details: USB-C power entry (VBUS/GND/CC/USB2) - Purchase Url: https://www.digikey.com/en/products/detail/gct/USB4105-GF-A/11198441 - Role: Connector - Datasheet URL: https://gct.co/files/drawings/usb4105.pdf - Manufacturer Name: GTC - Manufacturer Part Number: USB4105-GF-A - Part Type: USB C - Package: USB-C Receptacle **Pins:** - CC1 [pin 6] - CC2 [pin 12] - D- [pin 9] - D- [pin 7] - D+ [pin 10] - D+ [pin 8] - GND [pin 15] - GND [pin 1] - GND [pin 16] - GND [pin 2] - SBU1 [pin 11] - SBU2 [pin 5] - VBUS [pin 14] - VBUS [pin 13] - VBUS [pin 4] - VBUS [pin 3] ### J2 — [691243110004](https://www.flux.ai/tecnico01/691243110004-sgjss.md) - Role: Connector - Role Details: Electrode connector: I+ I- V+ V- - Part Type: https - Manufacturer Part Number: 691243110004 - Package or Case Code: //www.snapeda.com/parts/691243110004/Wurth+Elektronik/view-part/?ref=eda - Package: THT 3.5mm 4pos **Pins:** - 1 - 2 - 3 - 4 [pin ] ### J3 — [ARM JTAG SWD 10Pin 0.05" Connector](https://www.flux.ai/vasy_skral/arm-jtag-swd-10pin-005-connector.md) - Manufacturer Name: Analog Devices - Role Details: SWD header: SWDIO, SWCLK, NRST, 3V3, GND - Package: 2x5 1.27mm - Manufacturer Part Number: FTSH-105-01-L-DV-007-K - Datasheet URL: https://suddendocs.samtec.com/catalog_english/ftsh_smt.pdf - Part Type: Connector - Role: Debug Connector **Pins:** - ~RESET~ [pin 10] - GND [pin 5] - GND [pin 3] - GNDDetect [pin 9] - NC/TDI [pin 8] - SWDCLK/TCK [pin 4] - SWDIO/TMS [pin 2] - SWO/TDO [pin 6] - VTref [pin 1] ### J4 — [61300411121](https://www.flux.ai/adrian95/61300411121.md) - Manufacturer Part Number: 61300411121 - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300411121.pdf - Manufacturer Name: Wurth Elektronik - Package or Case Code: HDRV4W95P0X254_1X4_1016X254X854P - Role: Connector - Part Type: Connector - Role Details: UART header: 3V3, GND, TX, RX - License: https://creativecommons.org/licenses/by/4.0/ - Package: 1x4 2.54mm THT **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### U1 — [STM32WB5MMG](https://www.flux.ai/kicad-part-library/stm32wb5mmg.md) - Datasheet URL: https://www.st.com/resource/en/datasheet/stm32wb5mmg.pdf - Package or Case Code: ST-SiP-LGA-86-11x7.3mm - Part Type: RF Module - Manufacturer Name: STMicroelectronics NV - Manufacturer Part Number: STM32WB5MMG **Pins:** - ANT_IN [pin 58] - ANT_NC [pin 85] - NRST [pin 10] - PA0 [pin 3] - PA1 [pin 2] - PA10 [pin 28] - PA11 [pin 30] - PA12 [pin 29] - PA13 [pin 25] - PA14 [pin 26] - PA15 [pin 27] - PA2 [pin 1] - PA3 [pin 56] - PA4 [pin 55] - PA5 [pin 54] - PA6 [pin 53] - PA7 [pin 52] - PA8 [pin 50] - PA9 [pin 51] - PB0 [pin 44] - PB1 [pin 43] - PB10 [pin 47] - PB11 [pin 46] - PB12 [pin 41] - PB13 [pin 35] - PB14 [pin 37] - PB15 [pin 38] - PB2 [pin 48] - PB3 [pin 21] - PB4 [pin 20] - PB5 [pin 19] - PB6 [pin 39] - PB7 [pin 18] - PB8 [pin 14] - PB9 [pin 11] - PC0 [pin 12] - PC1 [pin 9] - PC10 [pin 22] - PC11 [pin 23] - PC12 [pin 24] - PC13 [pin 40] - PC2 [pin 8] - PC3 [pin 7] - PC4 [pin 49] - PC5 [pin 45] - PC6 [pin 36] - PC7 [pin 71] - PC8 [pin 83] - PC9 [pin 69] - PD0 [pin 33] - PD1 [pin 34] - PD10 [pin 77] - PD11 [pin 82] - PD12 [pin 66] - PD13 [pin 65] - PD14 [pin 63] - PD15 [pin 76] - PD2 [pin 68] - PD3 [pin 70] - PD4 [pin 73] - PD5 [pin 80] - PD6 [pin 81] - PD7 [pin 67] - PD8 [pin 75] - PD9 [pin 74] - PE0 [pin 79] - PE1 [pin 64] - PE2 [pin 78] - PE3 [pin 72] - PE4 [pin 42] - PH0 [pin 61] - PH1 [pin 62] - PH3-BOOT0 [pin 13] - RF_OUT [pin 59] - VBAT [pin 15] - VDDA [pin 6] - VDDSMPS [pin 17] - VDDUSB [pin 32] - VREF [pin 4] - VSS [pin 86] - VSS [pin 60] - VSS [pin 31] - VSS [pin 5] - VSS [pin 84] - VSS [pin 57] - VSSSMPS [pin 16] ### U2 — [TPS259270DRCR](https://www.flux.ai/adrian95/tps259270drcr.md) - Role Details: USB VBUS eFuse: OVP/UVLO/OCP + reverse-current blocking - Role: Protection - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps25927.pdf - Manufacturer Name: Texas Instruments - Package: VSON-10 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: TPS259270DRCR - Part Type: Power Management **Pins:** - BFET [pin 9] - DV/DT [pin 1] - EN/UVLO [pin 2] - EPAD [pin 11] - ILIM [pin 10] - OUT [pin 6] - OUT [pin 7] - OUT [pin 8] - VIN [pin 3] - VIN [pin 5] - VIN [pin 4] ### U3 — [TPS7A4701xRGW](https://www.flux.ai/kicad-part-library/tps7a4701xrgw.md) - Package: VQFN-20 - Role: Regulator - Package or Case Code: Texas_RGW0020A_VQFN-20-1EP_5x5mm_P0.65mm_EP3.15x3.15mm_ThermalVias - Role Details: 3.3 V LDO rail (set via feedback resistors) - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps7a47.pdf - Manufacturer Part Number: TPS7A4701xRGW **Pins:** - 0.1V [pin 12] - 0.2V [pin 11] - 0.4V [pin 10] - 0.8V [pin 9] - 1.6V [pin 8] - 3.2V [pin 6] - 6.4V [pin 4] - 6.4V [pin 5] - EN [pin 13] - EP [pin 21] - GND [pin 7] - IN [pin 15] - IN [pin 16] - NR [pin 14] - OUT [pin 20] - OUT [pin 1] - SENSE/FB [pin 3] ### U4 — [OP07DRZ](https://www.flux.ai/lcsc/op07drz.md) - Part Type: Precision OpAmps - JLCPCB Part Class: Extended Part - Manufacturer Part Number: OP07DRZ - Role Details: Howland current pump (bioimpedance injection) - Package: SOIC-8 - Manufacturer Name: ADI(亚德诺)/LINEAR(凌特) - LCSC Part Number: C690865 - Role: Op Amp - Package or Case Code: SOIC-8_L5.0-W4.0-P1.27-LS6.0-BL **Pins:** - DNC [pin 5] - IN- [pin 2] - IN+ [pin 3] - NULL [pin 8] - NULL [pin 1] - OUT [pin 6] - V- [pin 4] - V+ [pin 7] ### U5 — [INA128U](https://www.flux.ai/lcsc/ina128u.md) - Part Type: Instrumentation OpAmps - Role: Instrumentation Amplifier - Package: SOIC-8 - Role Details: INA128 front end for ECG/PTT measurement - JLCPCB Part Class: Extended Part - Package or Case Code: SOIC-8_L4.9-W3.9-P1.27-LS6.0-BL - Manufacturer Part Number: INA128U - LCSC Part Number: C2872992 - Manufacturer Name: TI(德州仪器) **Pins:** - REF [pin 5] - RG [pin 1] - RG [pin 8] - V- [pin 4] - V+ [pin 7] - VIN- [pin 2] - VIN+ [pin 3] - VO [pin 6] ### U6 — [MAX30102EFD+T](https://www.flux.ai/vasy_skral/max30102efdplust.md) - Manufacturer Part Number: MAX30102EFD+T - Symbol Style: Parametric - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Manufacturer Name: Maxim Integrated - Role Details: PPG (MAX30102) on I2C - Datasheet URL: https://datasheets.maximintegrated.com/en/ds/MAX30102.pdf - Package: MAX30102 - Role: Sensor **Pins:** - ~INT [pin 13] - GND [pin 12] - IR_DRV [pin 6] - NC [pin 8] - NC [pin 14] - NC [pin 1] - NC [pin 7] - PGND [pin 4] - R_DRV [pin 5] - SCL [pin 2] - SDA [pin 3] - VDD [pin 11] - VLED+ [pin 10] - VLED+ [pin 9] ### U7 — [LSM6DSOXTR](https://www.flux.ai/lcsc/lsm6dsoxtr.md) - LCSC Part Number: C481766 - Role: Sensor - Manufacturer Name: ST(意法半导体) - Package or Case Code: LGA-14L_L3.0-W2.5-P0.50-TL - Package: LGA-14 - Part Type: Attitude Sensors - JLCPCB Part Class: Extended Part - Manufacturer Part Number: LSM6DSOXTR - Role Details: IMU (LSM6DSOX) on I2C **Pins:** - CS [pin 12] - GND [pin 6] - GND [pin 7] - INT1 [pin 4] - INT2 [pin 9] - OSC_AUX [pin 10] - SCL [pin 13] - SCX [pin 3] - SDA [pin 14] - SDO_AUX [pin 11] - SDO/SA0 [pin 1] - SDX [pin 2] - VDD [pin 8] - VDDIO [pin 5] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/varshars1711/yelling-lime-memory-implanter](https://www.flux.ai/varshars1711/yelling-lime-memory-implanter).* --- *Generated from [https://www.flux.ai/varshars1711/yelling-lime-memory-implanter](https://www.flux.ai/varshars1711/yelling-lime-memory-implanter)*