AD7725 DEVELOPMENT KIT

A development kit for the AD7725 is available. This entire kit is made up of an Evaluation Board, an Eval-Control Board, Evaluation Software and Filter Design Software.

The Evaluation Board contains the AD7725 device, signal conditioning and Eval-Control-board interface circuitry. The Eval-Control Board is used to interface the Evaluation Board to a PC and thus enables multiple samples to be collected from the AD7725 for analysis on the PC using the Evaluation Software. The Evaluation Software allows the user to perform FFTs on the data and generate statistical histograms. It also gives the user information about the samples taken.

The filter design software is called 'FilterWizard' and has been developed specifically for generating user-defined filter configuration files to download to the AD7725. The files generated using this package can be loaded to the AD7725 using the Evaluation Software. Using FilterWizard, the user can select a range of different filter specifications including the filter type, bandwidth, rolloff, stopband frequency and stopband attenuation.

Download FilterWizard

The AD7725 Development Kit

Item	Order Number	Procurement Method	Price
AD7725 Evaluation Board	EVAL-AD7725CB	Order from Any Authorized ADI Channel	$150
AD7725 Evaluation Software (zip, 4,945,522 bytes)		Comes with EVAL-AD7725CB
Eval-Control Board (pdf, (pdf, 421,744 bytes)	EVAL-CONTROL BRD2	Order from Any Authorized ADI Channel	$250
Eval-Control Board Power Supply - U.S.A.	EVAL-110VAC-US	Order from Any Authorized ADI Channel	$20
Eval-Control Board Power Supply - Europe	EVAL-220VAC-EU	Order from Any Authorized ADI Channel	$20
Eval-Control Board Power Supply - UK	EVAL-220VAC-UK	Order from Any Authorized ADI Channel	$20
Filter Design Software	FilterWizard	Available here on this Website

Ordering Information
The following needs to be ordered, to obtain the entire evaluation kit:

• 1 x EVAL-AD7725CB
• 1 x EVAL-CONTROL BRD2
• 1 x POWER SUPPLY

The Evaluation Software comes with the Evaluation Board, and the Filter Design software can be downloaded from this website.

Filter Design

A user-defined filter configuration file can be generated using a digital filter design package called FilterWizard. This file can be loaded into the post processor on the AD7725 to program the multipliers and accumulators to perform user-specific filtering requirements.

FilterWizard
This digital filter design package allows the user to design different filter types and then generates the appropriate configuration file to be loaded into the Post Processor. Using the FilterWizard tool, the user can quickly design digital filters by specifying filter type, filter method, window type, and parameters specific to the chosen filter type. This application allows the user to specify the following different filter options:

• Single or Multistage
• Normalized or User-specified output frequency
• FIR or IIR
• Lowpass, Bandpass
• Window type
• Passband frequency and Ripple
• Stopband frequency, Attenuation, and Ripple

It also informs the user of the power dissipation of the AD7725 associated with the particular filter designed. This is to avoid filters being designed that result in the device exceeding the maximum power specifications.

The Magnitude, Phase and Impulse responses can be plotted so that the user knows the filter response (cutoff frequency, transition width, attenuation) before generating the coefficients. Once the filter characteristics have been decided, the configuration file is generated and will be of the correct format to be loaded directly into the Post Processor. When generating the configuration file, the application runs an optimization routine to determine the placement of each coefficient in the hardware in order to minimize power dissipation. After the routine has run, the application generates a diagram showing the tap usage.

The user interface of FilterWizard is shown in Figure 1.

AD7725 Evaluation Software
The AD7725 Evaluation Software comes with the Evaluation Board. The software allows the user to download the user-defined filter files to the AD7725. It also allows the user to take samples from the AD7725 on the Evaluation Board and analyze these samples to test the performance of different filters. It has a digital oscilloscope and performs FFTs and Statistical histograms on the conversion data. It also calculates SNR and THD values and gives the user other useful information about the conversion data.

The Evaluation Software graphical-user interface is shown in Figure 2.