A Sub-0.5 V Differential ED-CMOS/SOI Circuit with Over-1-GHz Operation

Takakuni DOUSEKI  Toshishige SHIMAMURA  Nobutaro SHIBATA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.4   pp.582-588
Publication Date: 2005/04/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.4.582
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Low-Power LSI and Low-Power IP)
Category: Digital
Keyword: 
ultralow voltage,  high-speed,  ED-MOS,  multi-Vth CMOS,  fully-depleted SOI,  

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Summary: 
This paper describes a speed-oriented ultralow-voltage and low-power SOI circuit technique based on a differential enhancement- and depletion-mode (ED)-MOS circuit. Combining an ED-MOS circuit block for critical paths and a multi-Vth CMOS circuit block for noncritical paths, that is, the so-called differential ED-CMOS/SOI circuit, makes it possible to achieve low-power and ultrahigh-speed operation of over 1 GHz at a supply voltage of less than 0.5 V. As two applications of the differential ED-CMOS/SOI circuit, a multi-stage frequency divider that uses the ED-MOS circuit in a first-stage frequency divider and a pipelined adder with a CMOS pipeline register are described in detail. To verify the effectiveness of the ED-CMOS/SOI circuit scheme, we fabricated a 1/8 frequency divider and a 32-bit binary look-ahead carry (BLC) adder using the 0.25-µm MTCMOS/SOI process. The frequency divider operates down to 0.3 V with a maximum operating frequency of 3.6 GHz while suppressing power dissipation to 0.3 mW. The 32-bit adder operates at a frequency of 1 GHz at 0.5 V.