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.
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