A Low Voltage Wide-Input-Range Bulk-Input CMOS OTA

Authors: Grech, Ivan¹; Micallef, Joseph²; Azzopardi, George²; Debono, Carl²

Source: Analog Integrated Circuits and Signal Processing, Volume 43, Number 2, May 2005 , pp. 127-136(10)

Publisher: Springer

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Abstract:

The G_m-C technique is extensively used for continuous-time filtering applications because it results in tunable, wideband and compact designs. In this paper, an OTA architecture using a novel bulk-input differential pair without the use of a tail current source is proposed. Good CMRR is still achieved by using the gate terminal to control the total current in the differential pair, via the use of a dummy pair. The OTA also exhibits a wide differential input range and good G_m-tunability. For this design, two standard double-poly double-metal CMOS processes were investigated: a 0.8

m process having a nominal threshold voltage of around 0.7 V and a 0.35

m process having a nominal threshold voltage of 0.5 V. Simulation results are presented for both designs while test results are presented, for the OTA, implemented using the 0.8

m process, used in a second order cochlea low-pass filter.

Keywords: low voltage; bulk-input; OTA; CMOS design

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s10470-005-6786-1

Affiliations: 1: Department of Microelectronics, University of Malta, Msida MSD 06, Malta, Email: igrech@eng.um.edu.mt 2: Department of Microelectronics, University of Malta, Msida MSD 06, Malta,

Publication date: 2005-05-01