capacitance to digital converter
For MEMS designers from AD
New A/D:
AD7745/46/47 - 24-Bit Capacitance to Digital Converter -http://www.analog.com/en/prod/0,2877,AD7747,00.html
The AD7747 is a high-resolution Σ-Δ capacitance to digital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture features inherent high resolution (24-bit no missing codes, 18 bit effective resolution at 16.6 Hz data rate), high linearity (±0.01%) and high accuracy (±4 fF factory calibrated). The AD7747 capacitance input range is ±8 pF (changing), while it can accept up to 17 pF absolute capacitance (not changing), which is compensated by an on-chip digital to capacitance converter (CAPDAC
The AD7745/AD7746 is a high-resolution Σ-Δ capacitance to digital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture features inherent high resolution (24-bit no missing codes, 19 bit effective resolution at 16.6 Hz data rate), high linearity (±0.01%) and high accuracy (±2 fF factory calibrated). The AD7745/AD7746 capacitance input range is ±4 pF (changing), while it can accept up to 17 pF absolute capacitance (not changing), which is compensated by an on-chip digital to capacitance converter (CAPDAC).
The AD7745 has one capacitance input channel, while the AD7746 has two channels. Each channel can be configured as single ended or differential. The AD7745/AD7746 is designed for floating capacitive sensors.