Inductive Rotary Sensor PCB

A 4-layer PCB on S1000-2M FR-4 laminate at 1.3±0.13mm thickness with immersion tin finish, designed as the coil substrate for inductive rotary position sensors. The 4-layer stackup carries primary excitation coils, secondary sine and cosine receive coils, and shielded reference loops in precisely etched copper patterns that determine angular accuracy. Inductive sensing is replacing magnetic Hall and resolver designs because it tolerates stray magnetic fields, requires no rare-earth magnets, and survives harsh contamination environments. Immersion tin provides a flat, solderable surface for the conditioning ASIC and connector. Typical use cases include EV motor rotor position sensing, throttle and pedal position sensors, EPS steering angle, robotic joint encoders, and industrial servo feedback. Production requires fine line-and-space etching with tightly controlled coil geometry, and AOI verification of every coil dimension to maintain electrical phase accuracy.