On-die Common Mode Noise Reduction Solution for High Speed Differential TO

Phenomenon of common mode current causes common mode noise which eventually leads to electromagnetic interference (EMI) to other electronic devices. The common mode current is generated from differential signals' timing, amplitude, and rise/fall time skews, due to non-ideal differential signaling from buffer and mismatches in differential trace design. Therefore, controlling common mode current is critical. Common mode current is typically addressed through the following approach during the design phase through implementing on-board discrete Common Mode Choke (CMC). It is also addressed through circumvention of signal timing skew, signal rise/fall-time skew, and signal amplitude skew, during the I/O buffer and layout design phase. This work presents a novel on-die Common Mode Noise Correction Feedback System (CMN-CFS) which provides the benefit of better EMI suppression and allow the removal of discrete CMC component, thus reducing the platform BOM, printed circuit board real estate needs and signal routing complexity.