Gain-Boosted Super Class AB OTAs Based on Nested Local Feedback

A new approach to design super class AB operational transconductance amplifiers (OTAs) with enhanced large-signal and small-signal performance is presented. It based on employing two nested positive negative feedback loops at the active load of an adaptively biased differential pair in weak inversion region. As a result, DC gain, gain-bandwidth product, settling time noise are improved compared conventional OTAs without extra circuit nodes or power consumption. Measurement results 180 nm CMOS test chip prototype show current boosting factor higher than 5000 nearly ideal efficiency. Due ultra-low quiescent currents high driving capability, exhibits excellent figure-of-merit (FOM L ) 236 V -1 . To illustrate applicability proposed approach, sample-and-hold (S/H) was designed fabricated same chip. S/H validate advantages proposal.