Gb/s enhanced eye pattern of BGA type board-to-board connector by embedded capacitor

Abstract

Nowadays, the data rate in digital board system has entered in over Gb/s and the enormously growing signal density has become a significant issue in the design of high-speed digital board system. Because of those reasons, the BGA type board-to-board connectors have been adopted successfully for high speed and high density. However, the reflection resulted from the inductance of the connector’s pin introduces the unacceptable Gb/s eye pattern. In this paper, 1Gb/s, 2Gb/s and 3Gb/s enhanced eye patterns of BGA type board-to-board connector are presented by embedded capacitor compensation against the pin inductance, which has much better electrical performance than SMD capacitor because of less unwanted parasitics. Furthermore, the flow of the determination of the optimal compensation capacitance for a general inductive connector is suggested. The distorted eye patterns and enhanced eye patterns are fully verified in simulations and experiments quantitatively for timing error sensitivity, best sampling time, noise margin and zero-crossing jitter.