A 1.3GHz wideband successive detection logarithmic amplifier

The basic principle design methodology, circuit structure and simulated results of a successive detection logarithmic amplifier (SDLA) which was developed in dielectric isolation Complementary Bipolar Process (CBIP) is presented in this paper. First of all, the principle of SDLA base on the transfer function of logarithmic amplifier is analyzed. Then, the design of circuit structure is optimized based on conclusion drawn by formula derivation. Finally, on the basis of mathematical analysis and with mathematical software MATLAB, the simulated results are analyzed, and the performance parameters of the circuits are evaluated effectively. Using the AC coupling and the typical structure which cascades amplitude-limiting amplifiers, we develop an SDLA whose bandwidth is much wider than 1.3GHz and whose logarithmic accuracy is less than plusmn1.0 dB. This logarithmic amplifier can be widely used in electronic equipment such as telecommunication, radar, electronic countermeasure.