EVAL-AD7719-EB

This Technical Note describes the evaluation board for the AD7719, Low Voltage, Low Power, 16&24- Bit, Dual

Sigma Delta ADC. The AD7719 is a complete analog front end for low frequency measurement applications. The AD7719 is factory calibrated and therefore does not require field calibration. The device AD7719 can accept low level input signals directly from a transducer and produce a serial digital output. It employs a sigma-delta conversion technique to realize up to 24 bits (Main ADC) or 16 bits (Auxiliary ADC) of no missing codes performance. The selected input signal is applied to a proprietary programmable gain (Main ADC only) front end based around an analog modulator.

The AD7719 modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via an on-chip control register allowing adjustment of the filter cutoff and output update rate. Full data on the AD7719 is available in the AD7719 datasheet available from Analog Devices and should be consulted in conjunction with this Technical Note when using the evaluation board. The evaluation board interfaces to the parallel port of an IBM compatible PC. Software is available with the evalu- ation board which allows the user to easily program the AD7719. Other components on the AD7719 Evaluation Board include two AD780s (precision 2.5V references), a 32.7680 kHz crystal and digital buffers to buffer signals to and from the PC.