An 8-bit 20 MS/s successive approximation register analog-to-digital converter for wireless intelligent control and information processing

Abstract

In this paper, a 1.8-V 10-bit 20MS/s successive approximation register (SAR) analog-to-digital converter (ADC) implemented in TSMC 0.18-um CMOS process is presented for wireless intelligent control and information processing. By applying low input capacitance that reduces driving difficulty of the ADC, the proposed SAR ADC achieves less sampling time. Also, asynchronous control logic is used which doesn't need an external high frequency clock to drive ADC. Measured results show that at the supply voltage of 1.8 V and sampling rate of 20 MS/s, the proposed SAR ADC achieves a spurious-free dynamic range (SFDR) of 55.1 dB, a signal-to-noise and distortion ratio (SNDR) of 44.5 dB, an effective number of bits (ENOB) of 7.1 bits, a differential nonlinearity (DNL) of 0.81 LSB, an integral nonlinearity (INL) of 1.24 LSB and a power consumption of 588 μ\Υ. The overall chip area is only 0.53 mm2 with a small ADC core area of 0.73 mm2.