一种高带宽、高电源抑制比的跨阻放大器

A Trans-Impedance Amplifier with High Bandwidth and High Power Supply Rejection Ratio

光电探测器是激光雷达的核心器件,通常由雪崩光电二极管(APD)阵列和相应的读出电路组成。跨阻放大器是读出电路的关键部分,其性能在很大程度上决定光电探测组件的性能。基于0.18μmCMOS工艺,针对大输入电容线性APD阵列的应用,设计了一种高增益、高带宽、高电源抑制比的跨阻放大器。基于无源反馈和有源前馈的补偿方式拓展了跨阻放大器带宽,同时实现了高增益和高带宽;设计了具有高电源抑制比的片上无电容低压差稳压器,提高了跨阻放大器的稳定性。仿真结果表明:跨阻增益为104.7dB·Ω,带宽为198.8MHz,等效输入噪声电流为3.65pA·Hz1/2,低频电源抑制比为-57.8dB,全带宽范围内电源抑制比低于-10.6dB。

Photodetector is the core component of LiDAR and is typically composed of avalanche diode(APD)array and corresponding readout circuits.Trans-impedance amplifier is the key block of readout circuits,and its performance determines the performance of photodetectors.For the application of large input capacitance linear APD array,a trans-impedance amplifier with high gain,high bandwidth and high power supply rejection ratio(PSRR)is designed with a 0.18μm CMOS process.The passive feedback and active feedforward compensation method extend the trans-impedance amplifier bandwidth while achieving high gain and high bandwidth.An on-chip capacitor-less low dropout regulator with high power supply rejection ratio is designed to improve the stability of the trans-impedance amplifier.Simulation results indicate that the trans-impedance gain is 104.7 dB·Ωand the bandwidth is 198.8 MHz.The equivalent input noise is 3.65 pA·Hz1/2.The low-frequency power supply rejection ratio is-57.8 dB,and the power supply rejection ratio is less than-10.6 dB in the full bandwidth range.