A wide temperature range micropower sensor interface circuit

A capacitive pressure sensor interface circuit featuring micropower consumption is presented. The sensitivity to leakage currents has been reduced, allowing operation at temperatures up to 130°C. Special attention has been paid to minimise aliasing in the sampled interface. An optimal combination of contradictory requirements on power consumption, temperature range and sampling speed was obtained by a very careful system and block design. An 11 bit resolution is guaranteed in the temperature range of -40°C up to 100°C. It may slowly decay above 100°C but ensures at least 5 bit at 130°C. The power consumption at room temperature is smaller than 4μA from a 2.4V to 4V battery.