Whenever engineers who need or use isolation amplifiers get together and talk about the improvements they would like to see most, the big three—cost, size, performance—are likely to be mentioned. The industrial or medical equipment manufacturer often has to make a choice of either buying an isolation amplifier or building his own. Cost is the key criterion for such a decision, but there are others as well. For example, the multichannel analog system designer usually runs into printed circuit board space limitations, since he almost always requires a lot of data channels on each PC board.