AD7731 is a low-noise, high-throughput 24-bit sigma-delta ADC with a proprietary programmable gain front end that allows it to directly accept a range of input signal ranges, including low-level signals, from a transducer. The part features three buffered differential programmable gain analog inputs that can be directly connected to analog sensors.
The AD7731 provides a complete analog front‑end for process‑control systems. It features a 24‑bit sigma‑delta converter, programmable output rates up to 6.4 kHz, and a programmable gain front‑end that supports three buffered differential inputs (configurable as five pseudo‑differential inputs). The device operates from a single +5 V supply and offers low offset and gain drift.
The part is available in 24‑lead plastic DIP, SOIC and TSSOP packages. Detailed specifications include input range options from ±20 mV to ±1.28 V, power‑supply rejection of up to 120 dB, and a normal‑mode power consumption of 67.5 mW. Timing characteristics, pin functions and ordering information are also provided.
| Resolution | 16 bits p‑p at 800 Hz output rate |
|---|---|
| Maximum Output Rate | 6.4 kHz (programmable) |
| Supply Voltage | Single +5 V (AVpp‑AGND) |
| Input Ranges (unipolar) | 0‑20 mV, 0‑40 mV, 0‑80 mV, 0‑160 mV, 0‑320 mV, 0‑640 mV, 0‑1.28 V |
| Input Ranges (bipolar) | ±20 mV, ±40 mV, ±80 mV, ±160 mV, ±320 mV, ±640 mV, ±1.28 V |
| Offset Drift | < 5 nV/°C |
| Gain Drift | < 2 ppm/°C |
| Package Options | 24‑lead DIP, 24‑lead SOIC, 24‑lead TSSOP |
| Power Consumption (Normal Mode) | 67.5 mW max |
| Operating Temperature Range | ‑40 °C to +85 °C |
The AD7731 can be programmed for output rates up to 6.4 kHz.
The device operates from a single +5 V supply (AVpp‑AGND).
It has three buffered differential programmable‑gain analog inputs, which can be configured as five pseudo‑differential inputs.
The offset drift is less than 5 nV/°C and the gain drift is less than 2 ppm/°C.