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 ither 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.