# 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~ix.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: Module - Part Type: Module - Role: Wireless Module - Role Details: Optional Wi-Fi/BLE module placeholder (not required for base BOM) - Manufacturer Name: Espressif Systems - Manufacturer Part Number: ESP32-WROOM-32U - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf **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~6uh.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: DFN-6/8 2.5x2.5 - Part Type: Sensor - Manufacturer Part Number: SHT31-DIS-B2.5KS - Manufacturer Name: Sensirion - Role Details: Temp/RH (SHT3x) on I2C - Datasheet URL: https://sensirion.com/media/documents/213E6A3B/63A5A569/Datasheet_SHT3x_DIS.pdf - Role: Sensor **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~cf.md) - Datasheet URL: https://gct.co/files/drawings/usb4105.pdf - Manufacturer Part Number: USB4105-GF-A - Part Type: USB C - Purchase Url: https://www.digikey.com/en/products/detail/gct/USB4105-GF-A/11198441 - Package: USB-C Receptacle - Role Details: USB-C power entry (VBUS/GND/CC/USB2) - Manufacturer Name: GTC - Role: Connector **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~09.md) - Package or Case Code: //www.snapeda.com/parts/691243110004/Wurth+Elektronik/view-part/?ref=eda - Role: Connector - Package: THT 3.5mm 4pos - Role Details: Electrode connector: I+ I- V+ V- - Manufacturer Part Number: 691243110004 - Part Type: https **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~y0b.md) - Package: 2x5 1.27mm - Part Type: Connector - Role Details: SWD header: SWDIO, SWCLK, NRST, 3V3, GND - Manufacturer Name: Analog Devices - Datasheet URL: https://suddendocs.samtec.com/catalog_english/ftsh_smt.pdf - Manufacturer Part Number: FTSH-105-01-L-DV-007-K - 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~pw9.md) - Manufacturer Name: Wurth Elektronik - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300411121.pdf - Package or Case Code: HDRV4W95P0X254_1X4_1016X254X854P - Part Type: Connector - Role Details: UART header: 3V3, GND, TX, RX - Package: 1x4 2.54mm THT - Manufacturer Part Number: 61300411121 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### U1 — [STM32WB5MMG](https://www.flux.ai/kicad-part-library/stm32wb5mmg~hlg.md) - Package or Case Code: ST-SiP-LGA-86-11x7.3mm - Manufacturer Name: STMicroelectronics NV - Part Type: RF Module - Manufacturer Part Number: STM32WB5MMG - Datasheet URL: https://www.st.com/resource/en/datasheet/stm32wb5mmg.pdf **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~fwe.md) - Manufacturer Part Number: TPS259270DRCR - Role Details: USB VBUS eFuse: OVP/UVLO/OCP + reverse-current blocking - Package: VSON-10 - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps25927.pdf - Part Type: Power Management - Manufacturer Name: Texas Instruments - Role: Protection **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~sjd.md) - Role Details: 3.3 V LDO rail (set via feedback resistors) - Package or Case Code: Texas_RGW0020A_VQFN-20-1EP_5x5mm_P0.65mm_EP3.15x3.15mm_ThermalVias - Package: VQFN-20 - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps7a47.pdf - Manufacturer Part Number: TPS7A4701xRGW - Manufacturer Name: Texas Instruments Inc. - Role: Regulator **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~sc3.md) - Manufacturer Part Number: OP07DRZ - Package: SOIC-8 - Part Type: Precision OpAmps - Role: Op Amp - JLCPCB Part Class: Extended Part - Package or Case Code: SOIC-8_L5.0-W4.0-P1.27-LS6.0-BL - LCSC Part Number: C690865 - Manufacturer Name: ADI(亚德诺)/LINEAR(凌特) - Role Details: Howland current pump (bioimpedance injection) **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~vfap.md) - Package: SOIC-8 - Role: Instrumentation Amplifier - JLCPCB Part Class: Extended Part - Manufacturer Name: TI(德州仪器) - Manufacturer Part Number: INA128U - Role Details: INA128 front end for ECG/PTT measurement - LCSC Part Number: C2872992 - Package or Case Code: SOIC-8_L4.9-W3.9-P1.27-LS6.0-BL - Part Type: Instrumentation OpAmps **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~r7h.md) - Manufacturer Name: Maxim Integrated - Role Details: PPG (MAX30102) on I2C - Package: MAX30102 - Manufacturer Part Number: MAX30102EFD+T - License: https://creativecommons.org/licenses/by/4.0/ - Role: Sensor - Part Type: Integrated Circuit - Symbol Style: Parametric - Datasheet URL: https://datasheets.maximintegrated.com/en/ds/MAX30102.pdf **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~3t8.md) - Manufacturer Name: ST(意法半导体) - Package: LGA-14 - Package or Case Code: LGA-14L_L3.0-W2.5-P0.50-TL - Role Details: IMU (LSM6DSOX) on I2C - LCSC Part Number: C481766 - Part Type: Attitude Sensors - Manufacturer Part Number: LSM6DSOXTR - JLCPCB Part Class: Extended Part - Role: Sensor **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~d1](https://www.flux.ai/varshars1711/yelling-lime-memory-implanter~d1).* --- *Generated from [https://www.flux.ai/varshars1711/yelling-lime-memory-implanter~d1](https://www.flux.ai/varshars1711/yelling-lime-memory-implanter~d1)*