This Technical Note describes the evaluation board for the AD7798 which is a Low Power, 16-Bit Sigma Delta ADC. The AD7798 is a complete analog front end for low frequency measurement applications. It contains three differential inputs and includes a low noise instrumentation amplifier, reference detect and a low side power switch. The update rate can be varied from 4.17 Hz to 470 Hz. It also has an on-board clock, eliminating the need for an external clock. It employs a sigma-delta conversion technique to realize up to 16 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 AD7798 accepts analog input signals of ±VREF/Gain, with Gain equal to 1 to 128. With a gain of 64 and the update rate programmed to 16.7 Hz, the rms noise is 85 nV. Simultaneous 50 Hz/ 60 Hz rejection is available at this data update rate also.
Technical notes are available in Adobe Acrobat Portable Document Format (PDF). To download the Technical Note, select the link below:
EVAL-AD7798EBZ Technical Note (pdf, 1,780,169 bytes)
The software provided runs under Windows 2000 and will allow the user to control all the functions of the AD7798 via the USB port of a PC. The software should be installed by running the SETUP.EXE program.
AD7798 Software (zip, 23.9 MB)