Abstract: A system and method is provided for extending the range of a common mode voltage of a differential comparator. In one embodiment, a differential comparator comprises an input stage with a negative voltage reference node, a first differential input coupled to a first differential pair transistor and operative to receive a first input signal, and a second differential input coupled to a second differential pair transistor and operative to receive a second input signal. The first input signal and the second input signal form a differential input signal. The differential comparator further comprises a common mode sensing circuit interconnected between the first differential input, the second differential input, and the negative voltage reference node. The common mode sensing circuit is operative to sense a common mode voltage of the differential input signal and set a voltage potential at the negative voltage reference node substantially equal to the sensed common mode voltage.

Abstract: Systems are provided for reducing electromagnetic emissions from a controller area network transceiver. A driver circuit is operative to transmit communications across an associated bus. A static driver replica circuit approximates a common-mode voltage associated with a dominant state associated with the bus. A receiver attenuator bias circuit forces a common-mode voltage associated with the driver circuit to be equal to the approximated dominant state common-mode voltage during a recessive state associated with the bus.

Abstract: An active termination for a transmission line comprising a reference impedance, a terminating impedance and a control circuit. The reference and terminating impedances are identical circuits made on the same integrated circuit in close proximity to one another. Both impedances are made of an active and a passive resistor in series. The active resistor is a CMOS transistor operated as a voltage controlled resistor. A control circuit senses the impedance of the reference impedance and generates a control signal to change the impedance of the reference and terminating impedances such that they are made equal to the impedance of the transmission line. An alternate embodiment of the invention comprises an active resistor and a passive resistor in series to form a terminating impedance network. A control circuit senses the voltage on the transmission line and adjusts the active resistor to terminate the transmission line with the correct value of resistance.

Abstract: An active termination for a transmission line comprising a reference impedance, a terminating impedance and a control circuit. The reference and terminating impedances are identical circuits made on the same integrated circuit in close proximity to one another. Both impedances are made of an active and a passive resistor in series. The active resistor is a CMOS transistor operated as a voltage controlled resistor. A control circuit senses the impedance of the reference impedance and generates a control signal to change the impedance of the reference and terminating impedances such that they are made equal to the impedance of the transmission line. An alternate embodiment of the invention comprises an active resistor and a passive resistor in series to form a terminating impedance network. A control circuit senses the voltage on the transmission line and adjusts the active resistor to terminate the transmission line with the correct value of resistance.

Abstract: An active termination for a transmission line comprising a reference impedance, a terminating impedance and a control circuit. The reference and terminating impedances are identical circuits made on the same integrated circuit in close proximity to one another. Both impedances are made of an active and a passive resistor in series. The active resistor is a CMOS transistor operated as a voltage controlled resistor. A control circuit senses the impedance of the reference impedance and generates a control signal to change the impedance of the reference and terminating impedances such that they are made equal to the impedance of the transmission line. An alternate embodiment of the invention comprises an active resistor and a passive resistor in series to form a terminating impedance network. A control circuit senses the voltage on the transmission line and adjusts the active resistor to terminate the transmission line with the correct value of resistance.