KC5373B-010 pinout
.–v–. CIC-TO-PAK -> |01 16| (*) PPU-A0 -> |02 15| –[C]-> CIC-TO-MB VCC – |03 14| <- ___ one of those pins connects to CIC-CLK VCC – |04 13| <- / GND – |05 12| – VCC +– |06 11| –+ +– |07 10| –+ +– |08 09| –+ | ‘—–’ | +————-+–[charge pump] -> CIC-RST
*Pin 16 is either tied to pin 15 or left floating, depending on the board
This chip was found in many NES NTDEC games and acted like CIC stun [1], [2]
It’s exact behviour is unknown, but PPU-A0 is probably a source of high frequency signal, whose current is amplified and available on pins 6-11. Next, going through charge pump, a negative voltage of around -4V is produced which disables NES’ internal CIC.
The role of other signals (CIC-TO-PAK, CIC-TO-MB, CIC-CLK) is open question.