应用于集成传感器的高精度接口芯片设计

摘要

In view of the weak signal of the interface of the integrated sensor ,noise sensitivity of low frequency ,a high preci-sion and low offset sensor interface chip was designed .Using nested chopper op-amp structure of programmable gain amplifier ,an-alog signal was isolated amplified by sensor sensing .The ADC was based on a 3 order 1-bit quantizer incremental sigma-delta modulator,which can suppress low frequency noise with correlated double sample (CDS)circuits.The chip was fabricated by 0.18μm CMOS double level polysilicon five layers metal technology .The test results show SNDR of the incremental sigmce-delta ADC achieves 90.8 dB and reaches 14.79 bit ENOB.%针对集成传感器接口信号微弱,对低频噪声敏感的特性,设计了一种高精度低失调的传感器接口芯片.采用嵌套斩波运放可编程增益放大器结构,隔离放大传感器感测到的模拟信号.ADC采用增量三阶单环单比特量化sigma-del ta调制器,积分电路运用了相关双采样技术,有效抑制了传感器接口电路的低频噪声.芯片采用0.18μm CMOS双层多晶硅五层金属工艺实现,测试结果表明,增量sigma-delta ADC的SNDR达到了90.8 dB,有效位数达到14.79位.