Design of Ultra-Low Power Amplifier Array in Weak Inversion Region for Electrocortigraphy (ECoG) Signal Acquisition
Abstract
Design and implementation of a novel ultra-low power (ULP) operational
transconductance amplifier (OTA) meant for recording Electrocorticography signals is
presented in this thesis. The design of the amplifier is done in weak inversion (or subthreshold) region of operation of MOSFET and was fabricated in IBM 130 nm standard
CMOS process. This thesis discusses the design and measurement challenges associated
with analog/mixed signal design in this region of operation. The ULP closed loop fully
differential OTA is designed for voltage gain of 40 dB for a frequency ranging from 15 Hz to
270 Hz with input referred noise voltage less than 5 uVrms across bandwidth of operation.
Total power dissipation for the novel complementary OTA structure designed in weak
inversion region is measured to be 216 nW for a supply of 0.4 V.