Integrated circuit based ac coupling topology

A capacitive coupling system configured as part of an integrated circuit for a differential pair to couple differential inputs to an amplifier, the system comprising:

• a positive path comprising:
• a positive path input configured to receive a positive path input signal, the positive path input signal having a DC component;
• a positive path first impedance element having an input and an output, the input configured to receive the positive path input signal such that the positive path first impedance element blocks the DC component, wherein the positive path first impedance element comprises a resistor in series with a capacitor;
• a positive path second impedance element configured to connect between the output of the positive path first impedance element and ground, the positive path second impedance element when combined with the positive path first impedance element form a voltage divider network;
• a negative path comprising:
• an input configured to receive a negative path input signal, the negative path input signal having a DC component;
• a negative path first impedance element having an input and an output, the input configured to receive the negative path input signal such that the negative path first impedance element blocks the DC component, wherein the negative path first impedance element comprises a resistor in series with a capacitor;
• a negative path second impedance element configured to connect between the output of the negative path first impedance element and ground, the negative path second impedance element when combined with the negative path first impedance element form a voltage divider network;
• the amplifier, which includes a biasing element, has having an input connected to the output of the negative path first impedance element and the output of the positive path first impedance element, and the amplifier receives the input signal without the DC component;
• and
• an impedance matching element comprising resistors connected between the positive path input and the negative path input and a capacitor connected to ground, the impedance matching element configured to match an input impedance of the amplifier to a data source.

A method for coupling an input signal, connected a data source, to a driver and blocking DC components of an input signal comprising:

• receiving the input signal from the data source, the input signal having a DC component;
• providing the input signal to a first impedance element which comprises a resistor in series with a capacitor, the first impedance element configured as part of an integrated circuit;
• blocking the DC component of the input signal with the first impedance element;
• providing an output from the first impedance element to a second impedance element which comprises a resistor in series with a capacitor, the second impedance element configured as part of the integrated circuit;
• establishing the input impedance with the second impedance element and the first impedance element to create an impedance matched signal;
• providing the impedance matched signal to the driver.

A method for coupling an input signal, connected a data source, to a driver and blocking DC components of an input signal comprising:

• receiving the input signal on an input path from the data source, the input signal having a DC component;
• providing the input signal to a first impedance element which comprises a resistor in series with a capacitor, the first impedance element configured as part of an integrated circuit;
• blocking the DC component of the input signal with the first impedance element;
• providing an output from the first impedance element to a second impedance element, the second impedance element has a resistor in series with a capacitor and is configured as part of the integrated circuit;
• providing the input signal to an impedance matching interconnect that interconnects the input path to either a second input path or ground node, the impedance matching interconnect comprising either a capacitor connected to ground or two or more resistors connected in series with a capacitor connected to ground;
• establishing the input impedance with the impedance matching interconnect, the first impedance element, and the second impedance element to create an impedance matched signal;
• and
• providing the impedance matched signal to the driver.