Raguram Damodaran

A 600-MHz VLIW DSP

A 600 MHz VLIW DSP, which implements the C64x VelociTI.2/spl trade/ architecture delivers 4800 MIPS, 2400 (16 b) or 4800 (8 b) million multiply accumulates at 0.3 mW/MMAC (16 b). The chip has 64 M transistors and dissipates 718 mW at 600 MHz and 1.2 V, and 200 mW at 300 MHz and 0.9 V. It has an 8-way VLIW DSP core, a 2-level memory system, and 2.4 GB/s I/O bandwidth. The DSP chip is implemented in 0.13 μm CMOS technology with 6-layer copper metalization.

A 65nm C64x+ Multi-Core DSP Platform for Communications Infrastructure

The combined processing power of three 1+GHz DSP cores and 65nm 7M CMOS integration delivers a WCDMA macro base-station on a single chip. The 300M transistor IC can perform up to 24000MIPS, 8000 16b MMACs per second, coupled with symbol-rate and chip-rate acceleration and dissipates less than 6W.

A 1.25GHz 0.8W C66x DSP Core in 40nm CMOS

The next-generation C66x DSP integrated fixed and floating-point DSP implemented in TSMC 40nm process is presented in this paper. The DSP core runs at 1.25GHz at 0.9V and has a standby power consumption of 800mW. The core transistor count is 21.5 million. The DSP core features 8-way VLIW floating point Data path and a two level memory system and delivers 40 GMACS or 10 GFLOPS floating point MAC performance at 1.25GHz.

A 800 MHz system-on-chip for wireless infrastructure applications

The 800MHz System-on-Chip implements the C64x VLIW DSP VelociTI.2/spl trade/ Architecture and delivers 6400 MIPS, 3200 16-bit MMACs, 6400 8-bit MMACs at 0.17 mW/MMAC (8 bit). The chip is implemented in state of the art 90 nm CMOS technology with 7-layer copper metalization. The core dissipates 1080 mW at 800 MHz, 1.2V. The system-on-chip is targeted for high performance wireless infrastructure application. It has an 8-way VLIW DSP core, a 2-level memory system, and an I/O bandwidth of 3.2GB/s.

Practical Clock Tree Robustness Signoff Metrics

Clock tree analysis and signoff is a key step in the design of any high performance chip. Though simple and intutive metrics like skew have been used to track clock tree quality, they are not sufficient for most practical purposes. Ideally, skew distribution obtained using a SSTA (Statististical Static Timing Analysis) on the clock trees can be used. But in most practical cases, the process information assumed by SSTA is not available. As a result, the signoff of clock skew robustness to variation effects is an often difficult problem to solve. In this work, we propose two metrics that can address this issue. These metrics can be used in three important ways. First, they can be used to determine during CTS whether the clock tree is good enough to go through rest of the backend flow or whether more tuning needs to be done to the clock tree. Second, they can be used to isolate any parts of the clock tree that behaves like a hot spot for clock skew across corners. Third, it can be used as a final signoff metric for clock tree to ensure that the tracking of the delays and skews can be expected to be good across all process points. We provide several experimental results from industry testcases demonstrating the utility of our metrics.

Context analysis and validation of lithography induced systematic variations in 65nm designs

The impact of lithography-induced systematic variations on the parametric behavior of cells and chips designed on a TI 65nm process has been studied using software tools for silicon contour prediction, and design analysis from contours. Using model-based litho and etch simulation at different process conditions, contours were generated for the poly and active layers of standard cells in multiple contexts. Next, the extracted transistor-level SPICE netlists (with annotated changes in CD) were simulated for cell delay and leakage. The silicon contours predicted by the model-based litho tools were validated by comparing CDs of the simulated contours with SEM images. A comparative analysis of standard cells with relaxed design rules and restricted pitch design rules showed that restrictive design rules help reduce the variation from instance to instance of a given cell by as much as 15%, but at the expense of an area penalty. A full-chip variability analysis flow, including model-based lithography and etch simulation, captures the systematic variability effects on timing-critical paths and cells and allows for comparison of the variability of different cells and paths in the context of a real design.