| 概要(Abstract) |
Recent technology trend requires TB/s bandwidth. To support this trend, data rate/pin in memories’ high-speed channels are continuously increasing. Therefore, to maintain TB/s bandwidth, maintaining signal integrity in the high-speed channel is mandatory. In the high-speed channel, not only channel parameters but also non-linear power/ground noise generated by simultaneous switching buffer outputs (SSOs) noise affect signal integrity. These noises are dominated by the occurrence probabilities of the SSO buffer combinations. However, conventional transient simulators and eye-diagram estimation methods fail to accurately estimate the eye-diagram considering these noise effects. In this presentation, a novel statistical eye-diagram method which considers non-linear power/ground noise and SSO noise is proposed. Four different output responses are derived: pull-up/down and steady states ‘one’ and ‘zero’. These responses are affected by the power/ground noise and SSO noise. Also, formula which derives occurrence probability of each response in function on aggressor buffer states is proposed. By mapping occurrence probabilities to the output response-sets, we can derive PDF of each responses-set. By defining main-cursors/ISI PDFs and taking convolution between main-cursor PDF and ISI PDF which affects each other, we can derive statistical eye-diagram considering impacts of power/ground noise and SSO noise. The proposed method is validated using HSPICE at the BER level where transient simulators can accurately estimate the eye-diagram. The proposed method is fast and accurate. The proposed method is applied for signal integrity analysis in HBM which is memory in form of 3D IC. |