AD7791

The EVAL-AD7791EBZ is a fully featured evaluation board for the AD7791,  a low power, 24-bit Σ-Δ analog-to-digital converter (ADC). The AD7791 is a complete analog front end for low frequency measurement applications. It is a low power device, consuming 65 μA typically with a 3 V power supply. It has an on-chip clock, which eliminates the need for an external clock. It employs a Σ-Δ conversion technique to realize up to 24 bits of no missing codes performance. The input signal is applied to an analog modulator. The modulator output is processed by an on-chip digital filter. The analog input channel of the AD7791 accepts analog input signals of ±VREF. At an output data rate of 16.6 Hz, the AD7791 has a peak-to-peak resolution of 19 bits. Simultaneous 50 Hz/60 Hz rejection is also available at this output data rate.

Full data on the AD7791 is available in the AD7791 data sheet from Analog Devices, Inc. It is recommended that the AD7791 data sheet be consulted in conjunction with this user guide when using the evaluation board.
The evaluation board interfaces to the USB port of a PC. Software that allows users to easily communicate with the AD7791 is available with the evaluation board.

The AD7791 evaluation board software must be installed before connecting the AD7791 evaluation board to the PC.

Another component on the AD7791 evaluation board is the ADP3303 high precision, low power, 3.3 V output voltage regulator, which powers the USB/serial peripheral interface (SPI).

CN-0216 is a precision weigh scale signal conditioning system. It uses the AD7791, a low power buffered 24-bit sigma-delta ADC along with dual external ADA4528-1 zero-drift amplifiers. This solution allows for high dc gain with a single supply.

This circuit allows great flexibility in designing a custom low-level signal conditioning front end that gives the user the ability to easily optimize the overall transfer function of the combined sensor-amplifier-converter circuit.