Design and analysis of silicone rubber-based TERAPOSER for LPDDR4 memory test

Abstract

Motivated by the increasing market demand for the high performance mobile devices, both the data rate and the number of pin of mixed-signal systems keep on increasing to realize multifunctional yet compact system designs. With this ascending technical trend, many signal integrity (SI) and power integrity (PI) problems such as ISI, jitter, crosstalk, simultaneous switching noise (SSN) have arisen that need to be thoroughly analyzed and tested. In order to accurately monitor the data signals of LPDDR4, a carefully designed test interposer considering such factors as impedance matching, minimization of skew and crosstalk needs to be proposed. In this paper, a novel test interposer scheme composed of a test interposer and silicone rubber sheets is proposed for LPDDR4 memory test. Through a series of simulations and measurements, we experimentally verify the proposed structures in time and frequency domains, and prove their accuracy and practicality.