Compact CMOS Wideband Instrumentation Amplifiers for Multi-Frequency Bioimpedance Measurement: A Design Procedure

Round 1

Reviewer 1 Report

This manuscript describes the design process of two bioimpedance instrumentation amplifiers using the ICF technique in a 180nm CMOS process. 

The work is quite complete. It follows the cookbook of integrated circuits design process and circuit characterization. Almost all the relevant parameters are deduced, simulated, and measured. The authors also use two FoM to compare the proposed IA to similar ones found in the literature. It is really quite good work.

My humble considerations:
- Since the gain Av is too low (4V/V), the author must refer to the statements from lines 26 to 37 and, mainly, lines 42-46 justifying this low voltage.
- The same analysis for CMRR in section 3.1 should be performed to offset voltage and PSRR. Or the authors should justify why these ones were not presented.
- If possible, the constructive blocks presented in Fig 1a and 1b should be highlighted in schematics from Fig 2 and Fig 3.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors present in this article the numerical simulation and experimental results for a compact CMOS wideband instrumentation amplifier. The article is very well written can be considered an example of hate. This article presented has all the necessary elements for a professionally elaborated paper: circuit analysis, numerical simulation and experimental results. The experimental results equally validate the circuit analysis and the numerical simulation. It is worth noting the circuit analysis in a very useful tutorial style for those who want to design instrumentation amplifiers. The contribution can be considered a scientific work with obvious didactic valence and I consider it from this perspective very useful and well organized.

• A recommendation that can be useful refers to Figure 7 which can be enlarged, possibly developed vertically for an extra resolution.
• Unfortunately, the didactic character is overshadowed by the lack of any reference to the software support used for simulation and measurements (note in the Author Contribution the software responsibility exists). In the absence of this information, it is difficult for readers of the journal to reproduce the results.
• In this respect, I consider useful a reference to all the instruments used or to other types of external support, including for the effective implementation of the proposed solutions if they are still mentioned in the Funding section of the paper.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf