Pratyush Kamal

Cost effective 28nm LP SoC technology optimized with circuit/device/process co-design for smart mobile devices

With newer technology nodes, circuit/device/process codesign is essential to realize the advantages of scaling. Leveraging co-design approach based on a well-established manufacturing flow, a cost effective 28 nm 4G SOC technology has been crafted. This 28 nm design strategy uses two sets of design rules and 7 different Vt cells with optimal power gating to achieve a 2.4× increase in gate density, 55% decrease in power and 30% gain in frequency with respect to the 45 nm counterpart. Relevant technical tradeoffs between the design/technology interactions are discussed to illustrate the codesign aspects.

Full chip impact study of power delivery network designs in monolithic 3D ICs

In this paper, we present a comprehensive study on the impact of power delivery network (PDN) on full-chip wirelength, routability, power, and thermal effects in monolithic 3D ICs. Our studies first show that the full PDN worsens routing congestion more severely in monolithic 3D ICs than in 2D designs due to the significant reduction in resources for 3D connections. The increase in signal wirelength translates into additional net switching power dissipation, which significantly contributes to total power. This in turn aggravates thermal issues in 3D ICs. In addition, we observe that PDN tradeoffs among wirelength, power, and thermal are more pronounced in monolithic 3D ICs than TSV-based 3D and 2D designs. This is because of the higher integration density and the severe competition between signal and power connections. Lastly, we develop various PDN design optimization techniques for monolithic 3D ICs and obtain up to 8% signal wirelength and 5% maximum temperature reduction under the given IR drop budget.

Full Chip Impact Study of Power Delivery Network Designs in Gate-Level Monolithic 3-D ICs

In this paper, we present a comprehensive study on the impact of power delivery network (PDN) on full-chip wirelength, routability, power, and thermal effects in gate-level monolithic 3-D (M3-D) ICs across different technology nodes. Our studies show that PDN worsens routing congestion more severely in M3-D ICs than in 2-D designs due to the significant reduction in resources for 3-D connections. The relative impact worsens at advanced technology nodes due to higher congestion of interconnects. The increase in signal wirelength translates into additional net switching power dissipation, which significantly contributes to total power. This in turn aggravates thermal issues further in 3-D ICs. In addition, we observe that PDN tradeoffs among wirelength, power, and thermal are more pronounced in M3-D ICs than through silicon via-based 3-D and 2-D designs because of the higher integration density and the severe competition between signal and power connections. We also compare the impact of PDN on full chip routing in M3-D ICs versus face-to-face 3-D ICs. Lastly, we use various PDN design optimization techniques for M3-D ICs at different nodes and obtain up to 13.9% signal wirelength and 17.6% total power reduction under the given IR drop budget.