The AD7747 is a 24-bit capacitance-to-digital converter with a temperature sensor. It offers high accuracy, high resolution, and is suitable for a wide range of applications.
The AD7747 is a high‑resolution 24‑bit capacitance‑to‑digital converter (CDC) designed for automotive, industrial and medical applications such as pressure, position, proximity, level, flow and impurity sensing. It integrates a temperature sensor, voltage reference and clock, allowing sensor connections without external components. The device supports single‑ended or differential capacitive sensors and provides active shielding to reduce parasitic capacitance.
The converter operates from a single 2.7 V to 5.25 V supply, works over –40 °C to +125 °C, and offers a conversion time of 124 ms. Detailed specifications include a capacitance input range of +8.192 pF, resolution down to 0.1 aF rms noise, and a 0.01 % INL. Pin‑out, timing diagrams, and typical performance curves are provided for system integration.
| Supply Voltage Range | 2.7 V to 3.6 V or 4.75 V to 5.25 V |
|---|---|
| Effective Resolution | 19.1 bit (effective) |
| Linearity (INL) | 0.01 % of full‑scale |
| Absolute Error (Capacitance) | ±10 fF at 25 °C |
| Power Consumption | 0.7 mA typical |
| Temperature Sensor Resolution | 0.1 °C |
| Temperature Sensor Accuracy | ±2 °C |
The AD7747 can be powered from 2.7 V to 3.6 V or from 4.75 V to 5.25 V.
The device provides an effective resolution of about 19.1 bits.