Open Collector Interface Driver
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14
The open collector interface driver converts diode-transistor logic (DTL) to transistor-transistor logic (TTL). It has the ability to sink the large current produced when a 40-ohm pull-up resistor is connected from the output to ground. This current is carried by the four parallel transistors in the output stage. The circuit uses two power supplies (3.0 and -1.5 volts) which are used to produce its off-chip logic levels of ground and -1.0 volt. The three inputs A, B and C give it a "positive NAND" logic function.