Noise Considerations in Pulse-Shaping Based TIA Channel Designed for a Pulsed TOF Laser Radar Receiver

In this study a detailed noise analysis and measurements of a time-of-flight (TOF) laser radar front-end amplifier are presented, in which an LC pulse shaper is combined with the non-linear feedback Trans-Impedance Amplifier in order to achieve a low noise and wide dynamic range TOF receiver. The noise of the receiver limits the single shot precision and sensitivity (i.e. the dynamic range at low end) of the receiver channel. It is shown that the proposed technique shapes the noise generated by various components of the frontend. Furthermore, in order to achieve the best possible noise performance, various compromises over different characteristics of the front-end (walk error, bandwidth) are discussed. The proposed front-end amplifier was fabricated as a part of a TOF receiver chip in a 0.35 μm standard CMOS process and our measurements show a trans-impedance gain of ~122 dBΩ, a bandwidth of ~200 MHz, and an input-referred equivalent current noise of ~60 nA.