Ultra-Low-Power Class-AB Bulk-Driven OTA with Enhanced Transconductance

Seong Jin CHOE  Ju Sang LEE  Sung Sik PARK  Sang Dae YU  

IEICE TRANSACTIONS on Electronics   Vol.E102-C   No.5   pp.420-423
Publication Date: 2019/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2018ECS6002
Type of Manuscript: BRIEF PAPER
Category: Electronic Circuits
weak inversion,  subthreshold region,  bulk-driven OTA,  class AB,  ultra-low power,  operational transconductance amplifier,  

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This paper presents an ultra-low-power class-AB bulk-driven operational transconductance amplifier operating in the subthreshold region. Employing the partial positive feedback in current mirrors, the effective transconductance and output voltage swing are enhanced considerably without additional power consumption and layout area. Both traditional and proposed OTAs are designed and simulated for a 180 nm CMOS process. They dissipate an ultra low power of 192 nW. The proposed OTA features not only a DC gain enhancement of 14 dB but also a slew rate improvement of 200%. In addition, the improved gain leads to a 5.3 times wider unity-gain bandwidth than that of the traditional OTA.