This is a chip that will cause an electronic item to either erase or destroy itself if certain conditions are met. They are most commonly used in the video arcade industry to render a game's motherboard useless if it is tampered with. The usual scheme is a ram chip powered by a small battery. It will be erased if it loses power or detects any irregularities. (This renders the game inoperable because the ram chip either holds a decryption table for the game's ROM, or the game's boot code).Many companies have been known to use these chips, but Capcom is by far the worst culprit, with many Capcom games from the late 80's and early 90's ceasing to function when their battery runs out.
This is supposed to be some perfect form of copy protection, but the fact is that the bootleggers and hackers always manage to break this protection eventually. The end result is that bootleg arcade games are still produced. Although not often as they once were, as the industry itself has slowed down to a standstill. Making bootlegging less attractive than it used to be. But because of these chips, thousands of law abiding owners of arcade hardware are stuck with a product that will self destruct in 5-12 years.
Fortunately many games can be restored by replacing a few chips on the motherboard. But this method often requires sacrificing a compatible gameboard that is still functioning. So you still end up losing a perfectly good game.
Some games also have an unintentional suicide chip in the form of a battery that tends to leak and ruin nearby ROM chips (such as Defender). If your gameboard has a battery of any kind other than the small watch style ones, then you should relocate it somewhere away from the board, to avoid any future damage. Always search the web first to make sure that you can safely remove the battery. If it cannot be safely removed, then you will have to wire a new one while the old one is still attached. Then you can safely remove the old one.