Various circuit techniques for implementing ultra high speed circuits use current-controlled CMOS (C.sup.3MOS) logic fabricated in conventional CMOS process technology. An entire family of logic elements including inverter/buffers, level shifters, NAND, NOR, XOR gates, latches, flip-flops and the like are implemented using C.sup.3MOS techniques. Optimum balance between power consumption and speed for each circuit application is achieve by combining high speed C.sup.3MOS logic with low power conventional CMOS logic. The combined C.sup.3MOS/CMOS logic allows greater integration of circuits such as high speed transceivers used in fiber optic communication systems.

According to an aspect, a current mode logic circuit comprise a first trim resistor and a second trim resistor connected to a supply voltage, a first transistor connected to an input voltage, a second transistor connected to an inverted input voltage and a third transistor and a fourth transistor connected to the first transistor and the second transistor, respectively, in a cascode manner in order to control magnitudes of an output voltage and an inverted output voltage of the current mode logic circuit.

A comparator is disclosed, for comparing a first input voltage (e+) with a second input voltage (e−) and generating a corresponding output voltage (out). The comparator comprises: a first input terminal (e+) for receiving the first input voltage: a second input terminal (e−) for receiving the second input voltage; an output terminal (out) for outputting the output voltage; a first supply rail (VCC) for providing a first supply voltage; and a second supply rail (VDD) for providing a second supply voltage. The comparator further comprises: a follower stage comprising a first follower stage supply terminal coupled to the first supply rail, a second follower stage supply terminal coupled to the second supply rail, a follower stage input terminal coupled to the second input terminal, and a follower stage output terminal for providing a follower stage output voltage; and an inverter stage comprising a first inverter stage supply terminal coupled to the first supply rail, a second inverter stage supply terminal coupled to the follower stage output terminal, an inverter stage input terminal coupled to the first input terminal, and an inverter stage output terminal for providing an inverter stage output voltage and coupled to the output terminal.

Various embodiments of the present technology may comprise methods and system for a resettable flip flop. The flip flop may receive a clock signal along a first circuit path and a reset signal along a second circuit path. The first circuit path provides a first high voltage value and a first low voltage value, and the second circuit path provides a second high voltage value that is greater than the first high voltage value and a second low voltage value that is less than the first low voltage value.

A comparator is disclosed, for comparing a first input voltage with a second input voltage and generating a corresponding output voltage. The comparator includes a follower stage coupled to a first supply rail and a second supply rail, a follower stage input terminal for the second input voltage, and a follower stage output terminal. The comparator also includes an inverter stage comprising a first inverter stage supply terminal coupled to the first supply rail, a second inverter stage supply terminal coupled to the follower stage output terminal, an inverter stage input terminal for the first input voltage, and an inverter stage output terminal for providing an inverter stage output voltage having a first range. A signal conditioning means is coupled to the inverter stage output terminal and generates a comparator output voltage at a comparator output terminal having a second range larger than the first range.

Various circuit techniques for implementing ultra high speed circuits use current-controlled CMOS (C.sup.3MOS) logic fabricated in conventional CMOS process technology. An entire family of logic elements including inverter/buffers, level shifters, NAND, NOR, XOR gates, latches, flip-flops and the like are implemented using C.sup.3MOS techniques. Optimum balance between power consumption and speed for each circuit application is achieve by combining high speed C.sup.3MOS logic with low power conventional CMOS logic. The combined C.sup.3MOS/CMOS logic allows greater integration of circuits such as high speed transceivers used in fiber optic communication systems.

A comparator is disclosed, for comparing a first input voltage with a second input voltage and generating a corresponding output voltage. The comparator includes a follower stage coupled to a first supply rail and a second supply rail, a follower stage input terminal for the second input voltage, and a follower stage output terminal. The comparator also includes an inverter stage comprising a first inverter stage supply terminal coupled to the first supply rail, a second inverter stage supply terminal coupled to the follower stage output terminal, an inverter stage input terminal for the first input voltage, and an inverter stage output terminal for providing an inverter stage output voltage having a first range. A signal conditioning means is coupled to the inverter stage output terminal and generates a comparator output voltage at a comparator output terminal having a second range larger than the first range.

A current-mode logic circuit is provided. The current-mode logic circuit includes a transmitter module. The transmitter module includes an output impedance circuit, a switch circuit, and a current source. The output impedance circuit provides an adjustable output resistor. The adjustable output resistor includes floating resistors and/or pull-up resistors. The switch circuit is coupled to the output impedance circuit. The switch circuit receives differential input signals, outputs differential output signals, and controls high-low level switching of the differential input signals and the differential output signals according to the adjustable output resistor. The current source is coupled to the output impedance circuit and the switch circuit. The current source provides currents to the output impedance circuit and the switch circuit. The floating resistors are resistors coupled between the differential output signals, and the pull-up resistors are resistors coupled between the differential output signals and a power source.

A current source logic gate with depletion mode field effect transistor (FET) transistors and resistors may include a current source, a current steering switch input stage, and a resistor divider level shifting output stage. The current source may include a transistor and a current source resistor. The current steering switch input stage may include a transistor to steer current to set an output stage bias point depending on an input logic signal state. The resistor divider level shifting output stage may include a first resistor and a second resistor to set the output stage point and produce valid output logic signal states. The transistor of the current steering switch input stage may function as a switch to provide at least two operating points.

A current-mode logic circuit is provided. The current-mode logic circuit includes a transmitter module. The transmitter module includes an output impedance circuit, a switch circuit, and a current source. The output impedance circuit provides an adjustable output resistor. The adjustable output resistor includes floating resistors and/or pull-up resistors. The switch circuit is coupled to the output impedance circuit. The switch circuit receives differential input signals, outputs differential output signals, and controls high-low level switching of the differential input signals and the differential output signals according to the adjustable output resistor. The current source is coupled to the output impedance circuit and the switch circuit. The current source provides currents to the output impedance circuit and the switch circuit. The floating resistors are resistors coupled between the differential output signals, and the pull-up resistors are resistors coupled between the differential output signals and a power source.