A SOI Multi-VDD Dual-Port SRAM Macro for Serial Access Applications

Nobutaro SHIBATA  Mayumi WATANABE  Takako ISHIHARA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E100-C   No.11   pp.1061-1068
Publication Date: 2017/11/01
Online ISSN: 1745-1353
Type of Manuscript: PAPER
Category: Integrated Electronics
Keyword: 
10T memory cell,  CMOS,  dual-port SRAM,  FIFO memory,  fully depleted SOI,  look-ahead operation,  multi-VDD,  serial access,  

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Summary: 
Multiport SRAMs are frequently installed in network and/or telecommunication VLSIs to implement smart functions. This paper presents a high speed and low-power dual-port (i.e., 1W+1R two-port) SRAM macro customized for serial access operations. To reduce the wasted power dissipation due to subthreshold leakage currents, the supply voltage for 10T memory cells is lowered to 1 V and a power switch is prepared for every 64 word drivers. The switch is activated with look-ahead decoder-segment activation logic, so there is no penalty when selecting a wordline. The data I/O circuitry with a new column-based configuration makes it possible to hide the bitline precharge operation with the sensing operation in the read cycle ahead of it; that is, we have successfully reduced the read latency by a half clock cycle, resulting in a pure two-stage pipeline. The SRAM macro installed in a 4K-entry × 33-bit FIFO memory, fabricated with a 0.3-µm fully-depleted-SOI CMOS process, achieved a 500-MHz operation in the typical conditions of 2- and 1-V power supplies, and 25°C. The power consumption during the standby time was less than 1.0 mW, and that at a practical operating frequency of 400 MHz was in a range of 47-57 mW, depending on the bit-stream data pattern.