A Low Power and High Throughput Self Synchronous FPGA Using 65 nm CMOS with Throughput Optimization by Pipeline Alignment

Makoto IKEDA
Kunihiro ASADA

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E93-A    No.7    pp.1319-1328
Publication Date: 2010/07/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E93.A.1319
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: VLSI Design Technology and CAD
self synchronous,  fpga,  pipeline alignment,  low power,  high throughput,  dynamic logic,  dual pipeline,  

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We detail a self synchronous field programmable gate array (SSFPGA) with dual-pipeline (DP) architecture to conceal pre-charge time for dynamic logic, and its throughput optimization by using pipeline alignment implemented on benchmark circuits. A self synchronous LUT (SSLUT) consists of a three input tree-type structure with 8 bits of SRAM for programming. A self synchronous switch box (SSSB) consists of both pass transistors and buffers to route signals, with 12 bits of SRAM. One common block with one SSLUT and one SSSB occupies 2.2 Mλ2 area with 35 bits of SRAM, and the prototype SSFPGA with 3430 (1020) blocks is designed and fabricated using 65 nm CMOS. Measured results show at 1.2 V 430 MHz and 647 MHz operation for a 3 bit ripple carry adder, without and with throughput optimization, respectively. We find that using the proposed pipeline alignment techniques we can perform at maximum throughput of 647 MHz in various benchmarks on the SSFPGA. We demonstrate up to 56.1 times throughput improvement with our pipeline alignment techniques. The pipeline alignment is carried out within the number of logic elements in the array and pipeline buffers in the switching matrix.