A 55-dB SNDR, 2.2-mW double chopper-stabilized analog front-end for a thermopile sensor

作者：Chen Chengying^*; Hu Xiaoyu; Fan Jun; Hei Yong

来源：Chinese Journal of Semiconductors, 2014, 35(5): 055003.

DOI：10.1088/1674-4926/35/5/055003

• Analog front-end
• chopper-stabilized
• Closed-loop structures
• Detection resolutions
• Effective number of bits
• Front-end amplifier
• Signal to noise and distortion ratio
• Thermopile sensors

A double chopper-stabilized analog front-end (DCS-AFE) circuit for a thermopile sensor is presented, which includes a closed-loop front-end amplifier and a 2nd-order 1 bit quantization sigma - delta modulator. The amplifier with a closed-loop structure ensures the gain stability against the temperature. Moreover, by adopting the chopper-stabilized technique both for the amplifier and 2nd-order 1-bit quantization sigma - delta modulator, the low-frequency 1/f noise and offset is reduced and high resolution is achieved. The AFE is implemented in the SMIC 0.18 μm 1P6M CMOS process. The measurement results show that in a 3.3 V power supply, 1 Hz input frequency and 3KHz clock frequency, the peak signal-to-noise and distortion ratio (SNDR) is 55.4 dB, the effective number of bits (ENOB) is 8.92 bit, and in the range of -20 to 85 degrees, the detection resolution is 0.2 degree.

• 出版日期2014