Current mode ethernet transmitter

A process for forming a transmission system for communicating data from a host through a transmission medium, the process comprising:

• providing a signal generator to generate a signal that is representative of the data from the host, the signal having high frequency components and other components;
• and
• providing a filter on a complementary metal-oxide-semiconductor chip, such that the filter can operate to remove the high frequency components of the signal while passing the other components of the signal as a filtered signal;
• wherein the step of providing a filter comprises the steps of:
• providing a plurality of transconductance cells;
• and
• providing a plurality of capacitors electrically connected with the plurality of transconductance cells, such that the electrical configuration of the transconductance cells and capacitors result in electrical operation as a particular combination of resistances, inductances and capacitances;
• wherein the step of providing the plurality of capacitors comprises the steps of:
• providing a substrate;
• providing a well near a surface of the substrate, the well doped with a first dopant type at first concentration of, the well;
• providing two doped regions within the well, such that an accumulation region of the well lies between the doped regions, the doped regions being configured to be electrically connected to a ground, the doped regions doped with the first dopant type at a second concentration, the second concentration greater than the first concentration;
• providing an oxide layer above the accumulation region;
• and
• providing a metal layer above the oxide layer, the metal layer being configured to be subjected to a voltage, such that when the metal layer is subjected to a positive voltage and the n+ doped regions are electrically connected to ground, a capacitance is formed between the accumulation region and the metal layer.

A transmission system for passing an Ethernet signal, representing data from a computer system, to an unshielded twisted pair (UTP) transmission cable, the transmission system comprising:

• a manchester encoder adapted to receive binary data from the computer system and to convert the binary data into a primary signal having varying voltage in accordance with the binary data, and for outputting the primary signal;
• and
• a complementary metal oxide semiconductor (CMOS) chip comprising,
• a filter adapted to receive the primary signal and to remove components of the primary signal that have a high frequency, while passing other components of the primary signal, the filter including a plurality of cascaded semiconductor devices, each semiconductor device being configured to simulate a functionality of a discrete parallel resistor-inductor-capacitor (RLC) circuit, such that each semiconductor device includes a plurality of transconductance cells and a plurality of capacitors that are electrically interconnected with the plurality of transconductance cells;
• wherein each capacitor is an n-channel transistor operating in accumulation mode.