Design of 90° Phase Shifter Circuit Based on DC Negative Feedback

The operational amplifier is the core module of the 90° phase shifter. This paper proposes a TCFC (transconductance capacitance feedback compensation) three-stage operational amplifier with a high FOM(Figure of Merit) value. It uses 180nm BCD process and a power supply voltage of 5V. The simulation results show that the operational amplifier open-loop gain is 140dB, the load capacitance is 10pF, the unit gain bandwidth is 21MHz, the phase margin is 50°, and the quiescent current consumed is 300uA. This high-performance operational amplifier is applied to the phase shifter based on DC negative feedback. The simulation results under cadence show that the phase shifter designed in this paper can achieve a 90° phase shift in the range of 20kHz-50kHz, with a deviation within 1°, and the phase shifter can work normally in a wide temperature range of −40°C-85°C and various process corner.