On frequency response and stability of an optical front–end with variable‐gain current amplifier using a bipolar junction transistor translinear loop

Abstract

A comparative analysis of implementations of an optical front-end with variable transimpedance intended for optical storage systems in two different BiCMOS technologies is given in this article. The variable-gain current amplifier within the optical front-end is designed by using a modified balanced type of the bipolar junction transistors translinear loop. The predictions of the optical front-end mathematical models are confirmed by the measured results. They show that a 0.6-mm BiCMOS silicon technology implementation with worse bipolar junction transistor parameters (unity-gain frequency, current gain b, and the Early voltage) gives much better stability than a 0.35-mm BiCMOS silicon-germanium technology implementation. As a consequence, the useful measured transimpedance dynamic range of the proposed optical front-end is 17.5 times larger in the 0.6-mm BiCMOS silicon technology than that in the 0.35-mm BiCMOS silicon-germanium technology.

A bipolar junction transistor EMC modeling method based on physical characteristic measurement and simplex optimization

“…In the Ig (I C )-V BE curve, the front part (0.3-0.4 V) is more in line with the approximation of (7). Therefore, the data between 0.3 and 0.4 V were used for least-squares linear fitting, and the results are shown in Figure 3C, from which I SE = 1.2141E-10A and N E = 2.8803 were obtained.…”

“…Therefore, the data between 0.3 and 0.4 V were used for least-squares linear fitting, and the results are shown in Figure 3C, from which I SE = 1.2141E-10A and N E = 2.8803 were obtained. If the data between V BE = 0.6 and 0.7 V is used, I B will be mainly dominated by the ideal forward diffusion current I CC /β F , rather than the approximate I BEL in (7). At this time, the slope obtained by fitting with I B is nearly parallel to the one with I C , about 0.434/(V T N F ), as shown in Figure 3D.…”

“…Bipolar junction transistors (BJTs) are widely used in various electronic systems [1][2][3][4][5][6][7] and are mainly responsible for power control, amplification, switching, and other functions. Due to the trends of miniaturization, integration, multifunctionality, and high frequency in electronic systems, the electromagnetic environment has become increasingly complex, resulting in numerous electromagnetic compatibility (EMC) issues.…”