Abstract
Based on the analysis of the inherent limitations of conventional OTA, this paper introduces a basic strategy by combinating linear-nonlinear adaptive current mirror and local cross-pair to solve the mutual restraint between AC and DC characteristics of the circuit. In order to simplify the multi-mode complicated circuit design, an analytical model for the new OTA is proposed, which is consistent with SPICE simulation results. Under the limitation of the static current consumption, the maximum limit of the circuit performance can be predicted by the proposed model. Under the condition of 29 μA quiescent current and 30 pF load capacitance, a chip is implemented in 0.18 μm CMOS technology, and the test results show that the DC gain, GBW and slew rate achieve 73 dB, 6 MHz and 14 V/μS, respectively, and the optimal performance of DC, AC and transient can be obtained almost simultaneously.
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Abbreviations
- DC:
-
Direct current
- AC:
-
Alternating current
- AV :
-
DC gain
- GBW:
-
Gain-bandwidth product
- SR:
-
Slew rate
- PM:
-
Phase margin
- OTA:
-
Operational transconductance amplifier
- FVF:
-
Flipped voltage follower
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Wu, J., Ke, M., Qu, N. et al. Modeling and designing of high-gain, wide-band and fast-speed operational transconductance amplifier. Analog Integr Circ Sig Process 71, 255–263 (2012). https://doi.org/10.1007/s10470-011-9736-0
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DOI: https://doi.org/10.1007/s10470-011-9736-0