High-linearity variable-gain transimpedance amplifier based on CMOS (complementary metal oxide semiconductor) process and working method thereof

Abstract

The invention discloses a high-linearity variable-gain transimpedance amplifier based on a CMOS process and a working method thereof. The high-linearity variable-gain transimpedance amplifier comprises a photodiode, a TIA transimpedance amplification circuit and a feedback resistor RF. The output end of the photodiode is connected with the TIA transimpedance amplifying circuit, and the feedback resistor RF is connected between the input end and the output end of the TIA amplifying circuit; the TIA transimpedance amplification circuit comprises a plurality of transconductance units which are sequentially connected in series. The design method of the high-linearity variable trans-impedance amplifier based on the phase inverter has the advantages that for the phase inverter type trans-impedance amplifier, the gain and the bandwidth of a trans-impedance amplifier and an open-loop amplifier can be integrally coordinated, high linearity in a full input range is achieved, and meanwhile it is guaranteed that the stability of the TIA is not affected.

Description

technical field [0001] The invention belongs to the technical field of optical communication receiver chip design, in particular to a high linearity variable gain transimpedance amplifier based on CMOS technology and a working method thereof. Background technique [0002] With the advent of the 5G era, the amount of data transmission, bandwidth requirements and Ethernet transmission standards have developed rapidly. Non-return-to-zero code (NRZ, the same below) transmission data has only two levels of "0" and "1" , and the bandwidth of the fiber amplifier is limited, which greatly compresses the amount of transmitted data. Therefore, when NRZ data transmission is not enough for people's needs, another data system, PAM-4, came into being. Compared with NRZ data carrying two bits of data, PAM-4 data containing four levels greatly increases the transmission rate. The amount of data. However, for optical communication systems, the transmission of PAM-4 data seems to have highe...

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Problems solved by technology

[0004] In the existing PAM-4 optical receiver solution, a variable gain amplifier is usually used after the TIA to adapt to a large input range. At this time, the flexibility of the TIA is poor, which leads to the deterioration of the linearity performance when the input signal is large; there are also The scheme adjusts the TIA, but only for the size of the feedback resistor in the TIA. Only changing the feedback resistor value will affect the TIA input impedance, the linearity performance will be deteriorated, and the closed-loop bandwidth of the TIA will be changed. At this time, when the bandwidth of the open-loop amplifier is insufficient, It may also cause stability problems of TIA;

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