The world’s first high-precision, single-chip converters that address the challenges of direct capacitance-to-digital and impedance-to-digital conversion are now available. The capacitance-to-digital converter (CDC) and impedance-to-digital converter (IDC) families combine advanced signal processing techniques with high levels of integration. The AD7745 CDC integrates all stages of capacitance-to-digital conversion on one chip. It reduces the costs associated with traditional multichip solutions by 65%.

With 24-bit resolution, the AD7745 is the industry’s highest-precision solution for interfacing with capacitive sensors. The first three devices in the CDC family (AD7745, AD7746, and AD7747) combine 24-bit resolution, low noise of 5 aF (10 to 18) per root hertz, and low power (1 mA max) with a complete range of on-chip analog functions.

The AD5933 IDC combines direct digital synthesis, analog-to-digital conversion, and digital signal processing techniques to provide a compact, integrated solution for precision impedance measurement. The AD5933 and AD5934 IDCs combine state-of-the-art digital and analog signal processing techniques to provide a compact integrated solution for impedance measurement. Using a direct digital synthesizer to provide a fine-frequency sweep capability combined with an analog-to-digital converter and sophisticated digital signal processing, these devices allow an external complex impedance (100 to 10 MW) to be excited with a known frequency of up to approximately 100 kHz. The devices are available in small 16-lead TSSOPs and 16-lead SSOPs with prices ranging from $4.60 to $4.95 (CDC) and $4.35 to $6.65 (IDC) per unit in 1,000-piece quantities.

Analog Devices, Inc.
www.analog.com