Package and chip design optimization for mid-frequency power distribution decoupling

Abstract

In this paper the mid-frequency power supply noise has been studied for a complex, next generation computer system by simulations of the complete module and board power distribution system. An MCM-D and MCM-C design and the effectiveness of on-chip and discrete on-module decoupling capacitors have been compared. The impact of delta-I ramping over several cycles and the impact of the continuous background switching and on-chip leakage have been analyzed. Conclusions are presented to optimize the chip and package design. IntroductionIt is of increasing importance to contain the mid-frequency power noise caused by on-chip switching activity variations, because of tighter supply voltage tolerances due to decreasing operating voltage and shorter cycle times, and because of faster and larger current transients due to increasing switching frequency, chip current, and extensive clock gating [ 11, [2]. Therefore low impedance power delivery and optimized decoupling is mandatory. Power noise simulations are essential in the early development phase of chip and package design. For mid-frequency decoupling optimization the

First- and second-level packaging of the z990 processor cage

“…PU7 (Figure 2) has the largest mid-frequency noise because this chip has module capacitors at two chip edges only, which increases the loop inductance [12]. The module capacitor locations are clearly indicated by the low peak noise in Figure 7.…”

“…The voltage change exhibits a damped mid-frequency oscillation with 42 MHz and 65-mV peak, which is just within the specified range for the mid-frequency noise. A detailed sensitivity analysis [12] has shown that the noise peak is determined for each chip on this MCM by the chip ⌬I, the on-chip capacitance and the inductance loop from Change of supply voltage on the corner PU chip (PU7) after a 20% change of on-chip switching activity at time zero (SPEED2000 simulation). Table 4 Total coupled noise as distributed from all adjacent signal lines.…”