Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001
· The cases come in many forms, but for inhouse development the DIP (Dual In-Line Pin) package is most popular, and most chips here are numbered with the same pin convention, unless specified.
· Chips are labelled with part numbers, for example the 74F147, will logically be equivalent to the 74LS147, except that they will have different rated speeds. The `F' signifies fast, and `LS' signifies low speed.
· There are extensive volumes of databooks available for chips, these are typically low cost, and available at any vendor of microchips.
· Many manufacturers make common chips, with the same IC numbers. But, there are also many proprietary chips. Be wary when selecting a non-standard IC, small purchases may be frowned upon by the supplier, making them hard to get in quantities of less than 1000.
· CMOS chips will need pull-up resistors on inputs.
· When TTL inputs have nothing attached they tend to "float high" and will indicate that an input is true.