Patent ID: 6411136
Filing Date: 2002-06-25
Classification: H04L

Abstract:
A CMOS differential line driver having a differential input with two input terminals and a differential analog output with two output terminals, which are each provided with a termination resistor, wherein:said input is a current input; the driver comprises two current amplifiers each coupled to a respective one of said two input terminals, and to a respective one of said two output terminals and provided for feeding with a first drive voltage; and the termination resistors are connected with first ends to said output terminals and have second ends for connection to a second drive voltage, wherein each said current amplifier has an input stage comprising a first current source, a first NMOS transistor connected with its gate and drain to said first current source and its source to a common lead; a second current source arranged to deliver a larger current than said first current source, a second NMOS transistor connected with its drain to said second current source, with its gate to the gate of the first NMOS transistor and with its source to said common lead; an output stage comprising a third NMOS transistor connected with its gate and drain to said second current source and its source to said common lead, a fourth NMOS transistor connected with its source to said common lead, with its gate to the gate of said third NMOS transistor and with its drain to an output; and said second NMOS transistor having a larger dimension in the ratio of W/L than said first NMOS transistor, and said fourth NMOS transistor having a larger dimension in the ratio of W/L than said third NMOS transistor.