EVAL-AD7942CB

EVAL-AD7942CB Datasheet

Evaluation Board AD768x/AD769x/AD794x

Part	Datasheet
EVAL-AD7942CB	EVAL-AD7942CB (pdf)

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Evaluation Board AD768x/AD769x/AD794x Preliminary Technical Data Versatile analog signal conditioning circuitry On-board reference, crystal oscillator and buffers 16-bit Parallel Buffered Outputs Ideal for DSP and data acquisition card interfaces Analog and digital prototyping area for breadbording the target system Stand-alone operation or Eval control board compatibility PC software for control and data analysis LabVIEW1 driver to develop custom application The EVAL-AD768x/AD769x/AD794xCB is an evaluation board for the AD768x/AD769x/AD794x high resolution ADC see the Ordering Guide at the end of this document for a product list . The AD768x/AD769x/AD794x evaluation board is designed to demonstrate the ADC's performance and to provide an easy to understand interface for a variety of system applications. A full EVAL-AD768x/AD769x/AD794xCB description of the AD768x/AD769x/AD794x is available in the Analog Devices AD768x/AD769x/AD794x data sheet and should be consulted when utilizing this evaluation board. The EVAL-AD768x/AD769x/AD794xCB is ideal for use with either Analog Devices EVAL-CONTROL BRD2/BRD3 EVAL-CONTROL BRDx to run the Analog devices evaluation software and to develop a specific application using LabVIEW, or as a stand-alone evaluation board. The EVAL-CONTROL BRDx is sold separately from the EVALAD768x/AD769x/AD794xCB, is required to run the evaluation software, is not required in stand alone mode and can be reused with many Analog Devices ADCs. 1 Labview is a trademark of National Instruments. Figure Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: Fax 2006 Analog Devices, Inc. All rights reserved. EVAL-AD768x/AD769x/AD794xCB TABLE OF CONTENTS Detailed Description 3 Using the EVAL-AD768x/AD769x/AD794xCB Software 3 Testing Methods 4 Preliminary Technical Data Use as a Standalone Evaluation Ordering Guide 18 ESD 18 Preliminary Technical Data EVAL-AD768x/AD769x/AD794xCB DETAILED Description The EVAL-AD768x/AD769x/AD794xCB includes a 5 V ultrahigh precision reference ADR435 , and a signal conditioning circuit with two opamps ADA4841 and digital logic. The board interfaces with a 96-way connector for the EVAL-CONTROL BRDx and a 26-pin IDC connector for the serial output interface. The EVAL-AD768x/AD769x/AD794xCB is a four-layer board carefully laid out and tested to demonstrate the specific high accuracy performance of the AD768x/AD769x/AD794x. Figure 2 through Figure 5 show the schematics of the evaluation board. The layouts of the board are shown in the following figures: Figure 6 Top-Side Silk-Screen Figure 7 Top-Side Layer Figure 8 Ground Layer Figure 9 Shield Layer Figure 10 Bottom-Side Layer Figure 11 Bottom-Side Silk-Screen The EVAL-AD768x/AD769x/AD794xCB has a flexible design that enables the user to choose among many different board configurations. A description of each selectable jumper is listed in Table 1, and the available test points are listed in Table The EVAL-AD768x/AD769x/AD794xCB is configured in the factory with the front-end amplifiers U6 and U7 set to a gain of The board is set to be powered through the EVALCONTROL BRDx. Buffered conversion data is available at the output parallel bus BD on U3 and on the 96-pin connector P3 and is valid during the falling edge of BBUSY on P3. Activity of the ADC turns on the on-board LED Power Supplies and Grounding The EVAL-AD768x/AD769x/AD794xCB has two power supply blocks: -SJ2 for the analog section including the AD768x/ AD769x/AD794x, the signal conditioning and the reference voltage circuitry. -SJ1 for the digital interface circuitry and the digital section of the ADC. These offer flexibility to evaluate the ADC and the surrounding circuitry with any power supply combination. Analog Input Ranges and Multiplexing The analog front-end amplifier circuitry U6 and U7 allows flexible configuration changes such as positive or negative gain, input range scaling, filtering, addition of a DC component, use of different op-amp and supplies. The factory configuration of the analog input of U6 and U7 is set at midscale. This allows a transition noise test without any other equipment. An FFT test can be done by applying a very low distortion AC source. As an option, an ADG739 multiplexer can be used in front of the ADC to demonstrate performances for multichannel applications. A second ADC can be mounted on the board to demonstrate the daisy-chain feature. Using the EVAL-AD768x/AD769x/AD794xCB Software This configuration requires to use the EVAL-CONTROL BRDx to interface the EVAL-AD768x/AD769x/AD794xCB with the PC. Software Description The EVAL-AD768x/AD769x/AD794xCB comes with software for analyzing the AD768x/AD769x/AD794x. One can perform a histogram to determine code transition noise, and Fast Fourier Transforms FFT's to determine the Signal-to-Noise Ratio SNR , Signal-to-Noise-plus-Distortion SINAD and TotalHarmonic-Distortion THD . The AC performances can also been evaluated after digital filtering averaging with enhanced resolution up to 32 bits . The front-end PC software has four screens Figure 12 is the Setup Screen where sample rate, number of samples are selected. Figure 13 is the Histogram Screen, which allows the code distribution for DC input and computes the mean and standard deviation. Figure 14 is the FFT Screen, which performs an FFT on the captured data, computes SNR, SINAD and THD. Figure 15 is the time domain representation of the output. When the on-board conversion CNV generation is used, a synchronous FFT can be achieved by synchronizing an external AC generator with the 10MHz Fsync signal J4 a 10 MHz signal, exact division of master clock MCLK . Figure 16 is the FFT Screen when averaging is used. Software Installation executable There is no need to have LabVIEW installed to run the executable. Double-click on Setup.exe in the LabVIEW exe folder from the CD-ROM shipped with EVAL-AD768x/AD769x/AD794xCB do not use the CD shipped with the EVAL-CONTROL BRDx EVAL-AD768x/AD769x/AD794xCB and follow the installation instructions. Developing your own application using LabVIEW You need LabVIEW or above to do this. Install the executable first, copy the folder LabVIEW VI and run the ADC vi example.vi Testing Methods Histogram To perform a histogram test, apply a DC signal to the input. It is advised to filter the signal to make the DC Source noise compatible with that of the ADC. C26 and C41 provide this filtering. AC Testing To perform an AC test, apply a sinusoidal signal to the evaluation board. Low distortion, better than 100dB, is required to allow true evaluation of the part. One possibility is to filter the input signal from the AC source. There is no suggested band-pass filter but consideration should be taken in the choice. Decimated Testing Averaging This test can be run with a shorted input to evaluate dynamic range or as the AC test. Setup Requirements • EVAL-CONTROL BRDx ADSP2189 • Evaluation board • Power supply AC 12V/1A source could be bought from Analog Devices sold separately from the EVALCONTROL BRDx The term AD768x/AD769x/AD794x is used in this document to represent all the ADCs listed in the ordering guide. ORDERING GUIDE Evaluation Board Model EVAL-AD7683CB EVAL-AD7684CB EVAL-AD7685CB EVAL-AD7686CB EVAL-AD7687CB EVAL-AD7688CB EVAL-AD7690CB EVAL-AD7691CB EVAL-AD7693CB EVAL-AD7694CB EVAL-AD7942CB EVAL-AD7946CB EVAL-CONTROL BRD2 EVAL-CONTROL BRD3 Product AD7683BRM AD7684BRM AD7685CRM AD7686CRM AD7687BRM AD7688BRM AD7690BRM AD7691BRM AD7693BRM AD7694BRM AD7942BRM AD7946BRM Controller Board not in production anymore Controller Board PR05105-0-3/06 PrF ESD CAUTION ESD electrostatic discharge sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

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Evaluation Board AD768x/AD769x/AD794x

Preliminary Technical Data

Versatile analog signal conditioning circuitry On-board reference, crystal oscillator and buffers 16-bit Parallel Buffered Outputs Ideal for DSP and data acquisition card interfaces Analog and digital prototyping area for breadbording the target system Stand-alone operation or Eval control board compatibility PC software for control and data analysis LabVIEW1 driver to develop custom application
The EVAL-AD768x/AD769x/AD794xCB is an evaluation board for the AD768x/AD769x/AD794x high resolution ADC see the Ordering Guide at the end of this document for a product list .

The AD768x/AD769x/AD794x evaluation board is designed to demonstrate the ADC's performance and to provide an easy to understand interface for a variety of system applications. A full

EVAL-AD768x/AD769x/AD794xCB
description of the AD768x/AD769x/AD794x is available in the Analog Devices AD768x/AD769x/AD794x data sheet and should be consulted when utilizing this evaluation board. The EVAL-AD768x/AD769x/AD794xCB is ideal for use with either Analog Devices EVAL-CONTROL BRD2/BRD3 EVAL-CONTROL BRDx to run the Analog devices evaluation software and to develop a specific application using LabVIEW, or as a stand-alone evaluation board. The EVAL-CONTROL BRDx is sold separately from the EVALAD768x/AD769x/AD794xCB, is required to run the evaluation software, is not required in stand alone mode and can be reused with many Analog Devices ADCs.
1 Labview is a trademark of National Instruments.

Figure

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel:

Fax 2006 Analog Devices, Inc. All rights reserved.

EVAL-AD768x/AD769x/AD794xCB

TABLE OF CONTENTS

Detailed Description 3 Using the EVAL-AD768x/AD769x/AD794xCB Software 3 Testing Methods 4

Preliminary Technical Data
Use as a Standalone Evaluation Ordering Guide 18 ESD 18

Preliminary Technical Data

EVAL-AD768x/AD769x/AD794xCB

DETAILED Description

The EVAL-AD768x/AD769x/AD794xCB includes a 5 V ultrahigh precision reference ADR435 , and a signal conditioning circuit with two opamps ADA4841 and digital logic. The board interfaces with a 96-way connector for the EVAL-CONTROL BRDx and a 26-pin IDC connector for the serial output interface.

The EVAL-AD768x/AD769x/AD794xCB is a four-layer board carefully laid out and tested to demonstrate the specific high accuracy performance of the AD768x/AD769x/AD794x. Figure 2 through Figure 5 show the schematics of the evaluation board. The layouts of the board are shown in the following figures:

Figure 6 Top-Side Silk-Screen

Figure 7 Top-Side Layer

Figure 8 Ground Layer

Figure 9 Shield Layer

Figure 10 Bottom-Side Layer

Figure 11 Bottom-Side Silk-Screen

The EVAL-AD768x/AD769x/AD794xCB has a flexible design that enables the user to choose among many different board configurations. A description of each selectable jumper is listed in Table 1, and the available test points are listed in Table

The EVAL-AD768x/AD769x/AD794xCB is configured in the factory with the front-end amplifiers U6 and U7 set to a gain of The board is set to be powered through the EVALCONTROL BRDx.

Buffered conversion data is available at the output parallel bus BD on U3 and on the 96-pin connector P3 and is valid during the falling edge of BBUSY on P3. Activity of the ADC turns on the on-board LED

Power Supplies and Grounding The EVAL-AD768x/AD769x/AD794xCB has two power supply blocks:
-SJ2 for the analog section including the AD768x/ AD769x/AD794x, the signal conditioning and the reference voltage circuitry.
-SJ1 for the digital interface circuitry and the digital section of the ADC.

These offer flexibility to evaluate the ADC and the surrounding circuitry with any power supply combination.

Analog Input Ranges and Multiplexing The analog front-end amplifier circuitry U6 and U7 allows flexible configuration changes such as positive or negative gain,
input range scaling, filtering, addition of a DC component, use of different op-amp and supplies.

The factory configuration of the analog input of U6 and U7 is set at midscale. This allows a transition noise test without any other equipment. An FFT test can be done by applying a very low distortion AC source.

As an option, an ADG739 multiplexer can be used in front of the ADC to demonstrate performances for multichannel applications.

A second ADC can be mounted on the board to demonstrate the daisy-chain feature.

Using the EVAL-AD768x/AD769x/AD794xCB Software

This configuration requires to use the EVAL-CONTROL BRDx to interface the EVAL-AD768x/AD769x/AD794xCB with the PC.

Software Description

The EVAL-AD768x/AD769x/AD794xCB comes with software for analyzing the AD768x/AD769x/AD794x. One can perform a histogram to determine code transition noise, and Fast Fourier Transforms FFT's to determine the Signal-to-Noise Ratio SNR , Signal-to-Noise-plus-Distortion SINAD and TotalHarmonic-Distortion THD . The AC performances can also been evaluated after digital filtering averaging with enhanced resolution up to 32 bits . The front-end PC software has four screens Figure 12 is the Setup Screen where sample rate, number of samples are selected.

Figure 13 is the Histogram Screen, which allows the code distribution for DC input and computes the mean and standard deviation.

Figure 14 is the FFT Screen, which performs an FFT on the captured data, computes SNR, SINAD and THD.

Figure 15 is the time domain representation of the output. When the on-board conversion CNV generation is used, a synchronous FFT can be achieved by synchronizing an external AC generator with the 10MHz Fsync signal J4 a 10 MHz signal, exact division of master clock MCLK .

Figure 16 is the FFT Screen when averaging is used.

Software Installation executable

There is no need to have LabVIEW installed to run the executable.

Double-click on Setup.exe in the LabVIEW exe folder from the CD-ROM shipped with EVAL-AD768x/AD769x/AD794xCB do not use the CD shipped with the EVAL-CONTROL BRDx

EVAL-AD768x/AD769x/AD794xCB
and follow the installation instructions. Developing your own application using LabVIEW You need LabVIEW or above to do this. Install the executable first, copy the folder LabVIEW VI and run the ADC vi example.vi

Testing Methods Histogram

To perform a histogram test, apply a DC signal to the input. It is advised to filter the signal to make the DC Source noise compatible with that of the ADC. C26 and C41 provide this filtering. AC Testing To perform an AC test, apply a sinusoidal signal to the evaluation board. Low distortion, better than 100dB, is required to allow true evaluation of the part. One possibility is to filter the input signal from the AC source. There is no suggested band-pass filter but consideration should be taken in the choice. Decimated Testing Averaging This test can be run with a shorted input to evaluate dynamic range or as the AC test. Setup Requirements
• EVAL-CONTROL BRDx ADSP2189
• Evaluation board
• Power supply AC 12V/1A source could be bought from Analog Devices sold separately from the EVALCONTROL BRDx
The term AD768x/AD769x/AD794x is used in this document to represent all the ADCs listed in the ordering guide.
ORDERING GUIDE

Evaluation Board Model EVAL-AD7683CB EVAL-AD7684CB EVAL-AD7685CB EVAL-AD7686CB EVAL-AD7687CB EVAL-AD7688CB EVAL-AD7690CB EVAL-AD7691CB EVAL-AD7693CB EVAL-AD7694CB EVAL-AD7942CB EVAL-AD7946CB EVAL-CONTROL BRD2 EVAL-CONTROL BRD3

Product AD7683BRM AD7684BRM AD7685CRM AD7686CRM AD7687BRM AD7688BRM AD7690BRM AD7691BRM AD7693BRM AD7694BRM AD7942BRM AD7946BRM Controller Board not in production anymore Controller Board

PR05105-0-3/06 PrF

ESD CAUTION

ESD electrostatic discharge sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived EVAL-AD7942CB Datasheet file may be downloaded here without warranties.

Datasheet ID: EVAL-AD7942CB 517905