Measurement and analysis of vertical noise coupling on low noise amplifier from on-chip switching-mode DC-DC converter in 3D-IC

Vertical noise coupling between sub-systems of mixed-signal system in 3D-IC can seriously degrades the performance of the system. In this paper, the amount of the vertical noise coupling in a 3D-IC and its source are measured and analyzed. A 200MHz on-chip DC-DC converter and 900MHz low-noise amplifier are chosen for the noise aggressor and victim, respectively. In the test vehicle, the low-noise amplifier chip is stacked on the on-chip DC-DC converter chip. Then, the amount of vertical noise coupling is measured at the output node of low-noise amplifier in time-domain. The measurement result shows that the amount of vertical noise coupling from on-chip DC-DC converter is much stronger than RF signal at low-noise amplifier output. Increase of silicon substrate thickness of low-noise amplifier chip (noise victim) does not reduce the vertical noise coupling, since the silicon substrate has conductivity. The main noise source of the vertical noise coupling is the switching node of the on-chip DC-DC converter. The dominant noise coupling mechanism is revealed as inductive coupling between on-chip inductors in noise aggressor and victim chip from a simple SPICE model of the vertical noise coupling. However, the capacitive coupling also has a considerable portion in the vertical noise coupling due to the large size of on-chip inductors in the on-chip DC-DC converter.