The performance of a transimpedance amplifier (TIA) can be enhanced by lowering the input impedance and applying the nonconstant gain-bandwidth product (GBP) technique. In this paper, a TIA of utilizing both properties is presented and the performance of the conventional and the proposed TIAs is analyzed theoretically and experimentally. The lowered input impedance increases the operational bandwidth whereas the nonconstant GBP decouples the tradeoff relation between the gain and the bandwidth of the conventional TIA. Since this advantage of the enhanced performance is achieved at the cost of degradation in noise characteristics, however, comprehensive noise analysis and in-depth comparison between the conventional and the proposed TIAs are investigated. In the proposed design, a common-base stage is inserted as the first stage in the conventional TIA for lowering the input impedance. In addition, the global feedback network is formed for achieving nonconstant gain-bandwidth. Compared with the conventional TIA, the measurement results show that the proposed TIA presents a 6.3× increase in GBP and a 33% increase in the spot noise, exhibiting an improvement of 3.5× in the overall figure-of-merit.

可以通过降低输入阻抗并应用非恒定增益带宽积（GBP）技术来增强跨阻放大器（TIA）的性能。本文提出了一种同时利用这两种性质的TIA，并从理论和实验上分析了常规TIA和拟议TIA的性能。较低的输入阻抗会增加工作带宽，而非恒定GBP会消除常规TIA的增益和带宽之间的折衷关系。由于以降低噪声特性为代价获得了增强的性能的优点，因此，我们对常规噪声和建议的TIA进行了全面的噪声分析和深入比较。在建议的设计中，在传统的TIA中，将共基级作为第一级插入以降低输入阻抗。另外，形成全球反馈网络以实现非恒定的增益带宽。与传统的TIA相比，测量结果表明，建议的TIA的GBP值增加了6.3倍，点噪声增加了33％，总体品质因数提高了3.5倍。