Chapter 12
The engineering
PCB Design Explorer
A wearable that measures microvolt-scale brain signals demands ruthless engineering. Explore the components that make HALO possible.
ADS1299 — Analog Front End
Converts microvolt-scale EEG into clean, high-resolution digital signals.
24-bit ΔΣ ADC, 3–8 channels, 250–500 Hz, input noise < 1 µVrms, PGA per channel, lead-off detection, internal reference buffer.
6-Layer Stackup
Dedicated ground and power planes shield sensitive analog measurements from digital noise.
- 1L1 — Top Layer (Components / Signals)
- 2L2 — GND Plane
- 3L3 — Inner Layer (Signals)
- 4L4 — Power Plane (3.3 / 1.8 / 1.2 V)
- 5L5 — Inner Layer (Signals)
- 6L6 — Bottom Layer (Components / Signals)