Design of low Transconductance OTA for Biopotential Signal Acquisition System

This paper presents the Design of low transconductance Operational Transconductance Amplifier (OTA) in 0.25μm CMOS technology. For bio-potential signal which is very weak in amplitude and very low in frequency. To capture this signal a OTA with transconductance in nanoSimens for Gm-C application required. with recent year the MOS technology is placing in to nanometer. The design of OTA in this work is the current division and current cancellation technique(CDCC). This technique is suitable for the amplifier with low transconductance for Gm-C application. The proposed technique makes use of the current which conventionally goes to ground, through a parallel path. The OTA is important building block for various analog circuit and systems. The OTA work in weak inversion mode with bais current of 0.31μA. PMOS transistor used in OTA to avoid the flicker noise .the simulated transconductance of this OTA in 0.25 μm technology is 15nS. The proposed OTA achieved the 26.3 dB dc gain and unity gain bandwidth product of 600 Hz while driving 15pF capacitive load. The OTA is designed in 0.25μm CMOS process using T-SPICEsimulator. The power consumption is 37 μW.