# FlowState Headband EVT1 ## Description FlowState Headband EVT1 — 4-Channel EEG Calibration Device Closed-loop EEG neurofeedback headband for theta/beta baseline calibration. 4-layer mixed-signal PCB, 40x30mm. Core ICs: - ADS1299-4PAG (TI) — 4-channel 24-bit EEG analog front end, SPI interface, 250 SPS - nRF5340 (Nordic) — Dual-core BLE 5.3 SoC, 128 MHz app core + 64 MHz network core Key requirements: - Separate analog and digital power domains (dual LDO: LP5907 for AVDD, AP2112 for DVDD) - Split analog/digital ground planes with single-point connection - 6 electrode inputs (4 active + 1 reference + 1 DRL) with individual TVS ESD protection on each - LIS2DH12 accelerometer (I2C) for motion artifact detection - MCP73831 USB-C battery charging (300-500 mAh LiPo) - 2.4 GHz chip antenna or PCB trace antenna at board edge with 10mm keepout - Conformal coating for sweat/moisture protection Reference designs: - Analog front-end: TI ADS1299 EVM (SBAS499) - Digital/BLE: Nordic nRF5340 DK reference schematic Critical constraint: Microvolt-level EEG signals — analog input routing and power supply filtering are the highest-priority layout concerns. ## Project Details - **Owner:** ninaphatak - **Created:** 3/26/2026 - **Last Updated:** 3/26/2026 - **Visibility:** Public ## Key Components ### U1 — [ADS1299-4PAGR](https://www.flux.ai/lcsc/ads1299-4pagr.md) - Manufacturer Part Number: ADS1299-4PAGR - JLCPCB Part Class: Extended Part - Manufacturer Name: TI(德州仪器) - LCSC Part Number: C2651574 - Package or Case Code: TQFP-64_L10.0-W10.0-P0.50-LS12.0-BL **Pins:** - ~{CS} [pin 39] - ~{DRDY} [pin 47] - ~{PWDN} [pin 35] - ~{RESET} [pin 36] - AVDD [pin 56] - AVDD [pin 59] - AVDD [pin 21] - AVDD [pin 19] - AVDD [pin 22] - AVDD1 [pin 54] - AVSS [pin 20] - AVSS [pin 32] - AVSS [pin 58] - AVSS [pin 23] - AVSS [pin 57] - 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 [pin 33] - DGND [pin 51] - DGND [pin 49] - DIN [pin 34] - DOUT [pin 43] - DVDD [pin 50] - DVDD [pin 48] - 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 [pin 29] - NC [pin 27] - 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] ### U2 — [NRF5340-QKAA-R7](https://www.flux.ai/jecstronic/nrf5340-qkaa-r7.md) - Manufacturer Name: Nordic Semiconductor ASA - Datasheet URL: https://infocenter.nordicsemi.com/pdf/nRF5340_PS_v1.2.pdf - Manufacturer Part Number: NRF5340-QKAA-R7 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit **Pins:** - ~RESET [pin AC31] - ANT [pin L31] - D- [pin B4] - D+ [pin B2] - DCC [pin A21] - DCCD [pin B10] - DCCH [pin J1] - DECA [pin A13] - DECD [pin A15] - DECN [pin A23] - DECR [pin A27] - DECRF [pin G31] - DECUSB [pin B6] - NC [pin D2] - NC [pin F2] - NC [pin K2] - NC [pin T2] - NC [pin AG31] - NC [pin AL31] - NC [pin AL1] - NC [pin A31] - NC [pin A1] - P0.00/XL1 [pin N1] - P0.01/XL2 [pin R1] - P0.02/NFC1 [pin W1] - P0.03/NFC2 [pin AA1] - P0.04/AIN0 [pin V2] - P0.05/AIN1 [pin Y2] - P0.06/AIN2 [pin AB2] - P0.07/AIN3 [pin AD2] - P0.08/TRACEDATA[3]/SCK [pin AH2] - P0.09/TRACEDATA[2]/MOSI [pin AJ1] - P0.10/TRACEDATA[1]/MISO [pin AK2] - P0.11/TRACEDATA[0]/CSN [pin AK4] - P0.12/TRACECLK/DCX [pin AK6] - P0.13/IO[0] [pin AL5] - P0.14/IO[1] [pin AK8] - P0.15/IO[2] [pin AK10] - P0.16/IO[3] [pin AL9] - P0.17/SCK [pin AK12] - P0.18/CSN [pin AK14] - P0.19 [pin AL13] - P0.20 [pin AK16] - P0.21 [pin AL15] - P0.22 [pin AK18] - P0.23 [pin AK20] - P0.24 [pin AL27] - P0.25/AIN4 [pin AK28] - P0.26/AIN5 [pin AL29] - P0.27/AIN6 [pin AK30] - P0.28/AIN7 [pin AE31] - P0.29 [pin U31] - P0.30 [pin B24] - P0.31 [pin B22] - P1.00 [pin M2] - P1.01 [pin P2] - P1.02/TWI [pin AE1] - P1.03/TWI [pin AF2] - P1.04 [pin AL19] - P1.05 [pin AK22] - P1.06 [pin AL21] - P1.07 [pin AK24] - P1.08 [pin AL23] - P1.09 [pin AK26] - P1.10 [pin R31] - P1.11 [pin B20] - P1.12 [pin B18] - P1.13 [pin A17] - P1.14 [pin B16] - P1.15 [pin B14] - SWDCLK [pin W31] - SWDIO [pin AA31] - VBUS [pin A5] - VDD [pin AL25] - VDD [pin E31] - VDD [pin AG1] - VDD [pin C1] - VDD [pin AL17] - VDD [pin AL11] - VDD [pin AL7] - VDD [pin AJ31] - VDD [pin AL3] - VDD [pin AC1] - VDD [pin N31] - VDD [pin U1] - VDD [pin B28] - VDD1 [pin A19] - VDD2 [pin B8] - VDD3 [pin L1] - VDDH [pin E1] - VSS [pin H2] - VSS [pin G1] - VSS [pin J31] - VSS [pin A25] - VSS [pin B12] - VSS [pin B26] - VSS_PAD [pin 51] - VSS_PAD [pin 47] - VSS_PAD [pin 50] - VSS_PAD [pin 48] - VSS_PAD [pin 35] - VSS_PAD [pin 44] - VSS_PAD [pin 49] - VSS_PAD [pin 36] - VSS_PAD [pin 38] - VSS_PAD [pin 43] - VSS_PAD [pin 45] - VSS_PAD [pin 37] - VSS_PAD [pin 41] - VSS_PAD [pin 39] - VSS_PAD [pin 46] - VSS_PAD [pin 104] - VSS_PAD [pin 40] - XC1 [pin C31] - XC2 [pin B30] ### U3 — [LIS2DH12TR](https://www.flux.ai/lcsc/lis2dh12tr.md) - Manufacturer Part Number: LIS2DH12TR - Product Info Url: https://lcsc.com/product-detail/Motion-Sensors-Accelerometers_STMicroelectronics_LIS2DH12TR_STMicroelectronics-LIS2DH12TR_C110926.html - Sensor Type: 3-axis digital accelerometer - Termination: 16-pin LGA - LCSC Part Number: C110926 - Part Type: Motion Sensors - Accelerometers - JLCPCB Part Class: Extended Part - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1810010329_STMicroelectronics-LIS2DH12TR_C110926.pdf - Package or Case Code: LGA-12_L2.0-W2.0-P0.50-BL - Manufacturer Name: ST(意法半导体) **Pins:** - CS [pin 2] - GND [pin 8] - GND [pin 6] - GND [pin 7] - INT1 [pin 12] - INT2 [pin 11] - RES [pin 5] - SCL/SPC [pin 1] - SDA/SDI/SDO [pin 4] - SDO/SA0 [pin 3] - VDD [pin 9] - VDD_IO [pin 10] ### U4 — [MCP73831T-2ACI/OT](https://www.flux.ai/adrian95/mcp73831t-2aciot.md) - Manufacturer Name: Microchip Technology - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP73831-Family-Data-Sheet-DS20001984H.pdf - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: MCP73831T-2ACI/OT **Pins:** - PROG [pin 5] - STAT [pin 1] - VBAT [pin 3] - VIN [pin 4] - VSS [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/ninaphatak/flowstate-headband-evt1](https://www.flux.ai/ninaphatak/flowstate-headband-evt1).* --- *Generated from [https://www.flux.ai/ninaphatak/flowstate-headband-evt1](https://www.flux.ai/ninaphatak/flowstate-headband-evt1)*