In this paper,since the Avalanche Photo Diode(APD)for Light-to-Voltage LTV conversion uses a high voltage in the operating range unlike other Photo Diodes(PD),the quenching resistor must be connected in series to prev...In this paper,since the Avalanche Photo Diode(APD)for Light-to-Voltage LTV conversion uses a high voltage in the operating range unlike other Photo Diodes(PD),the quenching resistor must be connected in series to prevent overcurrent when using the Transimpedance Amplifier(TIA).In such a case,quenching resistance may affect the transfer function of the TIA circuit,resulting in serious stability.Therefore,in this paper,by analyzing the effect of APD quenching resistance on the voltage and current loop transfer function of TIA,we proposed a loop analysis and a method for determining the quenching resistance value to improve stability.A TIA circuit with quenching resistance was designed by the proposed method and its operational stability was verified through simulation and chip fabrication.展开更多
Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental...Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental observations, the molten interlayer reacts vigorously with base metals, forming several continuous reaction layers. The typical interfacial microstructure of the joint can be expressed as GH99/（Ni,Cr）ss（γ）/TiNi（β2）＋TiNi2Al（τ4）＋Ti2Ni（δ）/δ＋Ti3Al（α2）＋Al3NiTi2（τ3）/α2＋τ3/TiAl. The maximum shear strength is 258 MPa for the specimen brazed at 1000°C for 10 min. Higher brazing temperature or longer brazing time causes coarsening of the phases in the brazing seam and formation of brittle intermetallic layer, which greatly depresses the shear strength of the joints.展开更多
文摘In this paper,since the Avalanche Photo Diode(APD)for Light-to-Voltage LTV conversion uses a high voltage in the operating range unlike other Photo Diodes(PD),the quenching resistor must be connected in series to prevent overcurrent when using the Transimpedance Amplifier(TIA).In such a case,quenching resistance may affect the transfer function of the TIA circuit,resulting in serious stability.Therefore,in this paper,by analyzing the effect of APD quenching resistance on the voltage and current loop transfer function of TIA,we proposed a loop analysis and a method for determining the quenching resistance value to improve stability.A TIA circuit with quenching resistance was designed by the proposed method and its operational stability was verified through simulation and chip fabrication.
基金Projects (50975062, 51105107, 51021002) supported by the National Natural Science Foundation of ChinaProjects (QC2011C044) supported by the Natural Science Foundation of Heilongjiang Province,China+1 种基金Project (20112302130005) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject (CUGA4130902510) supported by the China Postdoctoral Science Foundation Funded
文摘Reactive brazing of TiAl-based intermetallics and Ni-based alloy with Ti foil as interlayer was investigated. The interfacial microstructure and shear strength of the joints were studied. According to the experimental observations, the molten interlayer reacts vigorously with base metals, forming several continuous reaction layers. The typical interfacial microstructure of the joint can be expressed as GH99/（Ni,Cr）ss（γ）/TiNi（β2）＋TiNi2Al（τ4）＋Ti2Ni（δ）/δ＋Ti3Al（α2）＋Al3NiTi2（τ3）/α2＋τ3/TiAl. The maximum shear strength is 258 MPa for the specimen brazed at 1000°C for 10 min. Higher brazing temperature or longer brazing time causes coarsening of the phases in the brazing seam and formation of brittle intermetallic layer, which greatly depresses the shear strength of the joints.
