PM_K-1 hardware: resolve TQ2SA relay pinout; Stage 2 DAC + reconstruction filter
Relay residuals resolved from the Panasonic TQ-SMD connection diagram + contact-
resistance terminal pairs: coil=1/10, pole1 COM=3/NC=4/NO=2, pole2 COM=8/NC=7/NO=9,
pins 5/6 unused. (NC/NO sense also firmware-correctable via the GPIO drive.)
Stage 1b encoding already matched; docstring updated to "resolved".
Stage 2 (click source): PCM5102A DAC + 2nd-order Sallen-Key reconstruction filter.
- PCM5102A pinout verified (TI SLAS859C, TSSOP-20). 2.1Vrms GND-centered out (no
DC-block), charge-pump flying cap + VNEG, DEMP/FLT/FMT tied for I2S/normal/no-deemph,
SCK<-low-jitter MCLK, BCK/DIN/LRCK<-RP2350, XSMT pulled-up soft-mute.
- OPA1612 Sallen-Key LPF on OUTL. stage2_recon.cir confirms flat to 20kHz, -3dB at
74.8 kHz -- cleans delta-sigma HF residue without touching audio.
- ERC 0 errors; netlist 0 errors.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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