Design of Two-Stage Fully-Differential Driver in SAR ADC with Indirect Feedback Compensation Technique

This work presents a driver amplifier suitable for fully differential low-frequency Successive approximation register analog to digital converter (SAR ADC) with 14 bit resolution. The indirect feedback compensation technique is implemented for the compensation of a fully differential two-stage operational amplifier (op amp). The global common mode feedback (CMFB) circuit fix output common mode (CM). The PMOS input device reduces flicker noise at low frequency. The op amp design produces 73dB DC gain and 64 PM. The driver takes single-ended or fully differential input, consumes 430μW from 1.8V supply, has -93dB total harmonic distortion (THD) for 2V_PP differential output.