CDMA-based crosstalk cancellation for on-chip global high-speed links

摘要

Synchronous CDMA/spread spectrum methods, devices, and systems are used to suppress crosstalk in clock-forwarded on-chip interconnects. Transmitting a spread spectrum signal across on-chip interconnects for recovery at the terminus permit integrated chip designers to overcome the effects of capacitive cross-talk between adjacent data bus lines. The methods, devices, and systems provided herein improve cross-talk immunity between adjacent high speed signal lines by applying synchronous CDMA spread spectrum techniques to some or all of the high speed signal lines. Other methods, devices, and systems provided herein apply synchronous CDMA spread spectrum techniques to the concept of sending phantom signals to reduce the number of signal lines used to carry data.

主权项

1. A data bus on an integrated circuit die comprising:
a first data line, the first data line having a first end and a second end; a second data line adjacent to the first data line, the second data line having a first end and a second end; a first line driver including a first line driver input configured to receive a first data signal and a first line driver output in communication with the first end of the first data line, wherein the first line driver is configured to drive the first data signal onto the first data line; a first integrator including an input in communication with the second end of the first data line, wherein the first integrator is configured to receive the first data signal and integrate the first data signal to generate a first received output; a second line driver including a second line driver input and a second line driver output, wherein the second line driver output is in communication with the first end of the second data line; a first multiplier including a first input configured to receive a second data signal, a second input configured to receive a spread spectrum code, and an output in communication with the second line driver input, wherein the first multiplier is configured to modulate the second data signal based on the spread spectrum code to generate a modulated signal; a second multiplier including an output, a first input coupled to the second end of the second data line, and a second input configured to receive a spreading code, wherein the second multiplier is configured to de-modulate the modulated signal based on the spreading code to generate a de-modulated signal; and a second integrator in communication with the output of the second multiplier, the second integrator configured to integrate the de-modulated signal to generate a second received output; wherein the modulated signal received by the second multiplier is swing compensated.