Integral function method for determination of nonlinear harmonic distortion Antonio Cerdeira a, * , Miguel A. Alema ´n a , Magali Estrada a , Denis Flandre b a Section of Solid State Electronics, Department of Electrical Engineering, CINVESTAV, Av. IPN No. 2508, A.P. 14-740, 07300 Mexico D.F, Mexico b Laboratoire de Microe ´lectronique, UCL, Place du Levant 3, B-1348 Louvain-la-Neuve, Belgium Received 7 July 2003; received in revised form 29 April 2004; accepted 4 June 2004 The review of this paper was arranged by Prof. C. Hunt Abstract The analysis of harmonic distortion is of prime importance for the analog and mixed integrated circuits. Recently we presented a new integral function method (IFM), based on a completely new principle, which allows the calcula- tion of harmonic distortion using the DC output characteristic of devices or circuits. In this work we complement the integral function method to provide direct calculation of the following distortion figures: total harmonic distortion (THD), second harmonic distortion (HD2) and third harmonic distortion (HD3), voltage intercept points (VIP) and the intermodulation distortion (IMD). The comparison with the same distortion figures calculated by the Fourier coeffi- cients (FC), by direct AC measurements and from FFT in simulators, indicates that results obtained by IFM give an excellent agreement in the full range of the analyzed active regions. The IFM combines simplicity and computer effi- ciency with accuracy and with the possibility to easily analyze the distortion when varying any of the circuit or device parameters. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Integral function method; Harmonic distortion; Intermodulation distortion; Voltage intercept points; Amplifiers; Analog circuits; MOSFET 1. Introduction The analysis of harmonic distortion is of prime importance for the integration of analog and mixed inte- grated circuits using CMOS technology. Some examples in which harmonic distortion is a major specification are operational amplifiers, RF amplifiers, mixers and con- tinuous-time filters, both in single-ended or balanced/ fully-differential implementations. MOSFET transistors can be used either as linear resistors in mixers or filters or in the saturation regime in transconductance amplifi- ers. The most important nonlinear harmonic distor- tion figures usually analyzed are the total harmonic distortion (THD), the second harmonic distortion 0038-1101/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.sse.2004.06.001 * Corresponding author. Tel.: +52 55 5061 3780; fax: +52 55 5747 7114. E-mail addresses: cerdeira@mail.cinvestav.mx (A. Cer- deira), flandre@dice.ucl.ac.be (D. Flandre). Solid-State Electronics 48 (2004) 2225–2234 www.elsevier.com/locate/sse