An Incremental Zoom ADC With Quantization Level Shifting Technique For Over-Ranging Reduction

Zoom analog-to-digital converter (ADC) faces the problem of over-ranging, a redundancy of reference voltage range, which degrades the achievable signal-to-quantization-noise-ratio (SQNR). This paper presents an incremental zoom ADC with quantization level shifting technique to solve the over-ranging problem in an natural and effective way. Meanwhile, this technique also brings higher input range and area reduction in digital logic. After applying the technique, the simulation shows a 3.7 dB improvement in SQNR and 0.5 dB improvement in input range. The incremental zoom ADC is designed in a $0.18-\mu \mathrm{m}$ process, occupies $0.117 \mathrm{~mm}^{2}$ and achieves signal-to-noise ratio (SNR) of 104.6 dB with a bandwidth of 10 kHz in post simulation.