Electronically adjustable integrated circuit input/output termination method and apparatus
AssigneeTektronix, Inc.
InventorsArthur J. Metz, Daniel G. Knierim, Richard J. Huard
Life of this patent
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Abstract
An integrated circuit includes a termination for a transmission line having a predetermined characteristic impedance. The termination includes a controllable impedance circuit, including a multiplier, coupled to the transmission line. A reference impedance, placed external to the integrated circuit, has an impedance related to the characteristic impedance of the transmission line. A control circuit is coupled between the reference impedance and the controllable impedance circuit, and conditions the controllable impedance circuit to have the characteristic impedance responsive to the reference impedance
Claims20
In an integrated circuit, a termination circuit for a transmission line having a predetermined characteristic impedance, comprising:
- a controllable impedance circuit, coupled to the transmission line;
- a reference impedance, external to the integrated circuit, having an impedance related to the characteristic impedance;
- and
- a control circuit, coupled to the reference impedance and the controllable impedance circuit, for conditioning the controllable impedance circuit to have the characteristic impedance responsive to the reference impedance.
In an integrated circuit, a termination circuit for a plurality of transmission lines, each transmission line having a respective predetermined characteristic impedance, comprising:
- a plurality of controllable impedance circuits, each coupled to a corresponding one of the plurality of transmission lines;
- a reference impedance, external to the integrated circuit, having an impedance related to the respective characteristic impedances;
- and
- a control circuit, coupled to the reference impedance and the plurality of controllable impedance circuits, for conditioning the plurality of controllable impendance circuits to have the characteristic impedances of their corresponding transmission lines responsive to the reference impedance.
Dependencies are inferred from the claim text.