Patent ID: 6326804
Filing Date: 2001-12-04
Classification: H04L

Abstract:
An active termination circuit for terminating a signal traversing on a transmission line, comprising:a bottom clamping transistor coupled to a first localized potential having a bottom clamping transistor control node arranged for clamping said signal at about a first reference voltage;a bottom threshold reference transistor coupled to a first localized reference voltage supply configured to supply the first reference voltage, wherein the bottom threshold reference transistor provides a first bias voltage to said bottom clamping transistor control node that biases said bottom clamping transistor control node at about a first threshold voltage above said first reference voltage, said first threshold voltage representing a threshold voltage of said bottom clamping transistor;a top clamping transistor coupled to a second localized potential having a top clamping transistor control node arranged for clamping said signal at about a second reference voltage; anda top threshold reference transistor coupled to a second localized reference voltage supply configured to supply the second reference voltage, wherein said top threshold reference transistor provides a second bias voltage to said top clamping transistor control node that biases said top clamping transistor control node at about a second threshold voltage below said second reference voltage, said second threshold voltage representing a top clamping transistor threshold voltage,wherein any voltage excursions at said first localized potential does not affect said first localized reference voltage, and vice versa; and wherein any voltage excursions at said second localized potential does not affect said second localized reference voltage, and vice versa.