AD7745/AD7746 is a 24-bit capacitance-to-digital converter with temperature sensor, suitable for automotive and industrial applications. It is the new standard in single chip solutions and interfaces to single-ended or differential floating sensors. The resolution is down to 4 aF (that is, up to 21 ENOB)
The AD7745 and AD7746 are high‑resolution 24‑bit capacitance‑to‑digital converters with integrated temperature sensing. They support single‑ended or differential capacitive inputs, offer up to 21‑bit effective resolution, and operate from a single 2.7 V to 5.25 V supply.
The document provides full specifications, pin configurations, timing diagrams, typical performance curves, and absolute maximum ratings, enabling designers to integrate the devices into automotive, industrial, and medical applications.
| Supply voltage range | 2.7 V to 5.25 V |
|---|---|
| Operating temperature range | -40°C to +125°C |
| Effective resolution | 19 Bit |
| Output noise (rms) | 2 aF/√Hz |
| Full‑scale drift vs temperature | 5 ppm/°C (internal reference) |
The devices operate from a single 2.7 V to 5.25 V supply.
They are specified for -40 °C to +125 °C operation.
The AD7746 provides two capacitance input channels.
The on‑chip temperature sensor has a resolution of 0.1 °C.