The exponential function plays an important in communication and signal processing applications, medical equipment, hearing aid and disk drives [1]-[7]. The VGAs and AGCs can be designed by using the exponential function generator. Unfortunately, there is no intrinsic logarithmic MOS device that operates in saturation region, which is necessary to design such generators. Although CMOS transistors present exponential characteristics in weak inversion, their performance is poor in terms of speed and bandwidth. Although the exponential functions can be easily obtained in bipolar technology, bipolar techniques for AGCs and VGAs are not compatible for monolithic CMOSbased analog and mixed-signal circuits. There are two techniques to generate the exponential characteristics. The first is the pseudo-exponential generator [1]-[5]. The second is the Taylor series expression [6]-[7]. In this paper, the Taylor series expression is used for realizing the exponential characteristics. A general exponential function, based on the Taylor series expansion, can be expressed as