Definition - What does Chip-On-Board (COB) mean?
A chip-on-board (COB) is a chip that is mounted directly on a circuit board as opposed to being socketed. This kind of circuit board is also known as a “glop-top” for the blob of protective epoxy that protects and insulates the chip and its connections. All of the chip’s connections are hard-wired.
Techopedia explains Chip-On-Board (COB)
A chip-on-board is a chip that is wired directly to the motherboard. The chip is usually covered with a coating of epoxy or resin to protect it the way a heatsink does, as well as protecting the chips and wires from damage. This is where the term “glop-top” comes from. It is a cost-effective method of electronic packaging, but the disadvantage is that a chip cannot be replaced without desoldering, the way a socketed chip can. COBs are popular in small circuit boards because they require little physical space the way a heatsink does.