A SI incremental A/D converter for IC sensor interfaces

In this paper an incremental analog-to-digital converter (ADC) designed as part of the signal-conditioning circuitry of a pressure sensor interface is presented. For technological compatibility the switched-current (SI) technique has been used which does not need double polysilicon CMOS process. To overcome the lack of precision of this technique a conversion algorithm with digital correction has been chosen and circuit enhancements has been sought. Electrical simulations show the correct error cancellation performed by the proposed converter. Resolution of 10 bits is achieved for a 4 MHz master clock. A 1 μm CMOS prototype is being tested and some experimental results are given