Patent ID: 6121793
Filing Date: 2000-09-19
Classification: H03K

Abstract:
A logic device comprising:logic circuit means arranged to receive at least one signal input in the form of a differential signal in which the signal level is represented by a difference between two signal lines, to perform a logic function on said at least one signal input and to provide an output differential signal representing the result of said logic function on two output signal lines; andloading and current source means arranged to connect said logic circuit means to a power supply, said loading and current source means comprises a pair of loading elements connected respectively between a first power supply line and said output signal lines respectively and a pair of current source devices in the form of transistor devices connected in parallel between the logic circuit means and a second power supply line and having signals appearing at said output lines applied as control signals to the two transistor devices respectively, said loading and current source means being symmetrical with regard to said output signal lines whereby the voltage-time characteristics of said output differential signals for positive- and negative-going transitions are substantially symmetrical.