A 50 pA-Input-Bias-Current 134 dB-Open-Loop-Gain Operational Amplifier with a New CMFB and Base Current Compensation Circuit.

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Bibliographic Details
Title:	A 50 pA-Input-Bias-Current 134 dB-Open-Loop-Gain Operational Amplifier with a New CMFB and Base Current Compensation Circuit.
Authors:	Hong, Ting^1,2, Li, Wenchang^2,3 iwc@semi.ac.cn, Liu, Jian^1,4, Zhang, Tianyi²
Source:	Progress in Electromagnetics Research C. 2026, Vol. 166, p169-175. 7p.
Subjects:	Operational amplifiers, Electronic feedback, Electronic amplifiers, Electric currents, Bipolar integrated circuits
Abstract:	In the design of a precision operational amplifier (OPA), cancellation of the input bias current is a challenging issue, which is primarily limited by the current mirror mismatch and the low β value of the PNP transistors. This article proposes a new base current compensation design, which enables zero input-bias-current theoretically. The input stage of the circuit is an active load differential pair with a new common-mode feedback (CMFB) circuit based on the current reuse technique, which can provide a stable common-mode voltage for the amplifier without additional power consumption and area occupation. The proposed OPA is designed in a bipolar process with a core area of 2.85 mm x 1.5 mm. Simulation results show that this OPA achieves a 134_dB open-loop-gain, 50 pA input-bias-current @25°C, and a low supply current of 0.9 mA, which suggests a concise architecture of the OPA for low offset, low noise, low input bias current, and high gain. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	In the design of a precision operational amplifier (OPA), cancellation of the input bias current is a challenging issue, which is primarily limited by the current mirror mismatch and the low β value of the PNP transistors. This article proposes a new base current compensation design, which enables zero input-bias-current theoretically. The input stage of the circuit is an active load differential pair with a new common-mode feedback (CMFB) circuit based on the current reuse technique, which can provide a stable common-mode voltage for the amplifier without additional power consumption and area occupation. The proposed OPA is designed in a bipolar process with a core area of 2.85 mm x 1.5 mm. Simulation results show that this OPA achieves a 134_dB open-loop-gain, 50 pA input-bias-current @25°C, and a low supply current of 0.9 mA, which suggests a concise architecture of the OPA for low offset, low noise, low input bias current, and high gain. [ABSTRACT FROM AUTHOR]
ISSN:	19378718
DOI:	10.2528/PIERC25120703