## 3 Chip Layout and Post-Layout Simulation Results
The A2V converter can be utilized to detect the distance ranging up to 10.2 m. Yet, it should also be noted here that the proposed A2V converter, as a tester circuit, cannot fully detect and recover input currents smaller than 5 \(\mu\)A\({}_{\text{PP}}\), which might be attributed to the slightly deficient resolution of the PDH circuit. Figure 10b presents the simulated results of the T2V converter, where peak detection is achieved by the charging process in accordance with the time intervals between the rising edges of the START and STOP pulses. While the A2V converter can detect up to 200 \(\mu\)A\({}_{\text{PP}}\), the T2V converter operates effectively from 200 \(\mu\)A\({}_{\text{PP}}\) up to a maximum current of 5.5 mA\({}_{\text{PP}}\) that corresponds to the nearest detection range of 30 centimeters. Hence, a total dynamic range of 74.8 dB can be achieved by complementarily operating the A2V and T2V converters over widely various input currents. Figure 10: Simulated pulse responses of (**a**) the A2V converter with different input currents and (**b**) the T2V converter for various time intervals. Table 1 summarizes the performance deviations due to the process, voltage, and temperature (PVT) variations for three worst-case scenarios: (a) SS, 1.62 V and \(-45\)\({}^{\circ}\)C; (b) TT, 1.8 V and 27 \({}^{\circ}\)C; and (c) FF, 1.98 V and 125 \({}^{\circ}\)C. The simulation results indicate that the proposed OTA exhibits a transimpedance (TZ) gain variation of less than 6.7%, with a bandwidth deviation of no more than 10.8% from the nominal value of 830 MHz. Also, the noise current spectral density varies by a maximum of 29%. The transient responses of the A2V converter demonstrate an output voltage swing variation of within 28% for input currents below 200 \(\upmu\)App. The maximum deviation of the ToF detection range is 35 centimeters. Similarly, the T2V converter output varies by 28% in case (a) for an input current of 5.5 mA\({}_{\text{PP}}\) with a time-interval deviation (\(\Delta\)T) of 2.4 ns. In this case, the maximum deviation of the detection range is 8.4 centimeters. Hence, these results confirm the stable operation of the proposed LiDAR receiver. Ref. [18] realized a resistive feedback TIA with a replica circuit followed by a cascaded variable-gain amplifier for the gain control mechanism. It also employed a timing discriminator with differential voltage shifters to compensate for the walk errors. However, it required a large power consumption. Ref. [19] presented a wideband receiver for a 3D ranging LiDAR system that exploited a series resistor array with PMOS switches, hence extending the dynamic range up to 64 dB. However, the control signals of the switches were generated by using multiple comparators, where an external DC voltage was required for manual gain control. Also, the proposed wideband receiver dissip \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Parameters** & **SS** & **TT** & **FF** \\  & **1.62 V.** & **-45 °C** & **1.8 V.27 °C** & **1.98 V, 125 °C** \\ \hline \multirow{4}{*}{OTA} & TZ gain (dB\(\Omega\)) & 69 (\(\pm\)3.1\%) & 66.9 & 62.4 (\(-\)6.7\%) \\  & Bandwidth (MHz) & 740 (\(-\)10.8\%) & 830 & 758 (\(-\)8.67\%) \\  & Noise current spectral density (pA/\(\sqrt{\text{Hz}}\)) & 12.4 (\(-\)21.5\%) & 15.8 & 20.4 (\(+\)29\%) \\  & Output voltage amplitude (\(\text{V}_{\text{PP}}\)) & 0.94 (\(-\)17\%) & 1.13 & 1.35 (\(+\)19\%) \\  & \# 5 \(\upmu\)Ap input current & & & & \\  & Output voltage amplitude (\(\text{V}_{\text{PP}}\)) & 1.25 (\(+\)11\%) & 1.12 & 1.44 (\(+\)28\%) \\  & \# 200 \(\upmu\)App (\(\Delta\)T = 10.7 ns) input current & & & & \\  & Output voltage amplitude (\(\text{V}_{\text{PP}}\)) & 0.92 (\(-\)14\%) & 1.07 & 1.16 (\(+\)8.4\%) \\  & \# 5.5 mA\({}_{\text{PP}}\) (at = 2.4 ns) input current & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: PVT variation simulations of the proposed LiDAR receiver.