Reset generator

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File:Cd1 resetgen.jpg
PST518B in a CD1 system.

The Mitsumi PST518B is a reset generator, it holds the NeoGeo in reset as long as the power supply is below 4.4V.

It has an open-collector output tied to the RST line (not RESET !), which is shared with the reset button on the home system. The line goes to NEO-B1.

Not to be confused with the watchdog reset.

Internal schematic

Datasheet: File:PST518B.pdf.

Replacement

Not pin-compatible: TL7757CL

Pin-compatible: MCP120-450GI/TO