Comment on “construction of CDBA and CDTA behavioral models and the applications in symbolic circuits analysis”

The comment is related to the recently published paper given by Tan et al. (Analog Integrated Circuits and Signal Processing (Tan et al. Analog Integr Circuits Signal Process, 2013)). It depicts the model construction of CDBA and CDTA active devices for symbolic circuit analysis. Nevertheless, the proposed CDTA model can be further simplified to enhance the analysis efficiency. The modified CDTA models are given in this comment and one of the proposed models is applied to practical symbolic nodal analysis to demonstrate the feasibility.