Bandwidth extension circuit of cascode trans-impedance amplifier based on CMOS (complementary metal oxide transistor) technology

A technology of transimpedance amplifier and cascode, which is applied in the direction of improving the amplifier to expand the bandwidth, DC-coupled DC amplifier, amplifier, etc., can solve problems such as difficult to meet bandwidth requirements, and achieve extended bandwidth, high gain-bandwidth product, and reduced Effect of Input Impedance

Inactive Publication Date: 2018-11-30
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although the transimpedance amplifier based on the classic RGC structure of the standard CMOS process has obtained gigahertz bandwidth, the input parasitic capacitance mainly composed of the junction capacitance of the photodetector and the parasitic effect of the post-stage capacitance still have a great influence on the overall bandwidth of the amplifier. It is difficult to meet the increasing bandwidth demand

Method used

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  • Bandwidth extension circuit of cascode trans-impedance amplifier based on CMOS (complementary metal oxide transistor) technology
  • Bandwidth extension circuit of cascode trans-impedance amplifier based on CMOS (complementary metal oxide transistor) technology
  • Bandwidth extension circuit of cascode trans-impedance amplifier based on CMOS (complementary metal oxide transistor) technology

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Embodiment 1

[0024] An embodiment of the present invention provides a bandwidth expansion circuit of a cascode transimpedance amplifier based on a CMOS process, see Figure 1-Figure 3 , the circuit is a completely symmetrical structure;

[0025] Among them, the circuits of the left and right parts include: the traditional main-level cascode amplifier, the new cascode auxiliary amplifier and the end source follower;

[0026] The circuit adopts a novel cascode structure to assist the amplifier to shield the Miller effect; the parallel PMOS structure provides greater transconductance for the common-gate NMOS transistor;

[0027] The circuit shields part of the parasitic capacitance through a π-type matching network, and adds an end source follower to isolate the parasitic capacitance of the rear stage, thereby improving the overall bandwidth of the circuit;

[0028] The circuit adopts the RGC structure to effectively reduce the input impedance and better isolate the input capacitance mainly ...

Embodiment 2

[0032] Combine below Figure 1-Figure 3 The scheme in Example 1 is further introduced, see the following description for details:

[0033] figure 1 A novel differential cascode transimpedance amplifier designed for utilizing a series of cascode transimpedance amplifier bandwidth expansion methods proposed in the embodiment of the present invention, the amplifier has a left-right symmetrical structure (that is, a completely symmetrical structure).

[0034] where the current source I PD and capacitance C PD The parallel structure of is the equivalent circuit model of the photodetector. The new differential cascode transimpedance amplifier is mainly composed of three parts: the traditional primary cascode amplifier, the new cascode auxiliary amplifier and the end source follower.

[0035] Among them, the transistor M 21 , resistance R 21 , R 22 Constitute the main common gate amplifier; transistor M 22 , M 23 , M P , resistance R 23 and inductance L 1 form the auxilia...

Embodiment 3

[0072] Combine below Figure 4 and Figure 5 The scheme in embodiment 1 and 2 is carried out feasibility verification, see the following description for details:

[0073] Based on UMC 0.18μm CMOS process, the circuit structure is simulated and parameters are optimized. Figure 4 Shown is a comparison diagram of the frequency response of the new differential cascode transimpedance amplifier and the classic RGC transimpedance amplifier.

[0074] Using the bandwidth expansion method provided by the embodiment of the present invention, the designed new differential cascode transimpedance amplifier has a gain of 61.16dB and a -3dB bandwidth of 8.36GHz. Compared with the classic RGC structure, the gain is slightly improved. Under the premise, the bandwidth has been greatly optimized.

[0075] Figure 5 It is a schematic diagram of the noise current comparison of the new differential cascode transimpedance amplifier and the classic RGC transimpedance amplifier. Compared with the...

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Abstract

The invention discloses a bandwidth extension circuit of a cascode trans-impedance amplifier based on CMOS (complementary metal oxide transistor) technology. The bandwidth extension circuit is of completely bilaterally symmetric structure; each of the left and right parts of the bandwidth extension circuit includes a traditional primary cathode-input amplifier, a novel cascode auxiliary amplifierand a terminal source follower; the novel cascode structure is used herein to assist the amplifiers in shielding Miller effect; the concurrent PMOS (P-channel metal oxide semiconductor) structure provides greater transconductance for the cathode-input NMOS (N-channel metal oxide semiconductor); stray capacitance is partially shielded with a Pi-shaped matching network shielding portion; the terminal source follower is added to isolate stray post-capacitance, and total bandwidth of the circuit herein is increased; the circuit herein helps effectively reduce input impedance via RGC structure, andinput capacitance that is mainly of photoelectric detector junction capacitance is better isolated; the circuit herein gains adjustment and optimization for component parameters; differential structure is utilized so that working bandwidth of the circuit herein is greatly widened.

Description

technical field [0001] The invention relates to the fields of optical communication, optical interconnection and visible light communication, in particular to a series of new methods for extending the bandwidth of cascode transimpedance amplifiers. Background technique [0002] The advent of the big data era has accelerated the demand for broadband network development, and the rapid growth of traffic means that optical fiber transmission systems with higher speeds and wider frequency bands are required. Traditional copper interconnection is limited by factors such as crosstalk and loss, and it has been difficult to adapt to ultra-high-speed data transmission and exchange. However, the optical interconnect technology, which uses light as the carrier of information transmission, has many advantages such as low high-frequency loss, low crosstalk noise, and wide operating frequency bandwidth. Although HBT / HEMT (Heterojunction Bipolar Transistor / High Electron Mobility Field Effe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03F1/48H03F3/45
CPCH03F1/483H03F3/45179H03F2203/45024
Inventor 谢生邱博文毛陆虹
Owner TIANJIN UNIV
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