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Evaluation Board for the AD7265/AD7266

EVAL-AD7265/AD7266

Rev. 0

Evaluation boards are only intended for device evaluation and not for production purposes.

Evaluation boards are supplied “as is” and without warranties of any kind, express, implied, or

statutory including, but not limited to, any implied warranty of merchantability or fitness for a

particular purpose. No license is granted by implication or otherwise under any patents or other

intellectual property by application or use of evaluation boards. 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. Analog Devices reserves the right to change devices or specifications at any time

without notice. Trademarks and registered trademarks are the property of their respective owners.

Evaluation boards are not authorized to be used in life support devices or systems.

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

Tel: 781.329.4700

www.analog.com

FEATURES

Full-featured evaluation board for the AD7265 and AD7266

EVAL-CED1Z compatible

Standalone capability

On-board analog buffering and voltage reference

On-board single-ended-to-differential conversion

Various linking options

PC software for control and data analysis when used with

EVAL-CED1Z

GENERAL DESCRIPTION

This data sheet describes the evaluation board for the AD7265

and the

AD7266, which are dual, 12-bit, high speed, low power

successive approximation ADCs that operate from a single 2.7 V to

5.25 V power supply and feature throughput rates up to 2 MSPS.

Full details on the AD7265 and the AD7266 are available in the

device data sheets, which are available from Analog Devices,

Inc., and should be consulted in conjunction with this data

sheet when using the evaluation board.

On-board components include an

AD780, which is a pin

programmable 2.5 V or 3 V ultrahigh precision band gap

reference, nine

AD8022 dual op amps, and a 7S04 digital buffer.

Various link options are explained in Table 1.

Interfacing to this evaluation board is through a 96-way connector.

This 96-way connector is compatible with the EVA L-CED1Z,

which is available from Analog Devices. External sockets are

provided for a number of signals, including the V

REF

input, the

analog inputs, and the digital inputs and outputs.

FUNCTIONAL BLOCK DIAGRAM

AD7265/AD7266

SCLK

DRIVE

EXTERNAL

REF

96-WAY EDGE CONNECTOR

EXTERNAL SUPPLY

S/E TO DIFF

CONVERSION USING

AD8138

OPTIONAL BIAS-UP

CIRCUITRY FOR

S/E TO DIFF

OPERATION

BIPOLAR

INPUT

BIPOLAR

INPUT

UNIPOLAR

OUTPUT

UNIPOLAR

OUTPUT

BIPOLAR

SINGLE-ENDED

INPUT

S/E TO DIFF

CONVERSION USING

AD8138

BIPOLAR

SINGLE-ENDED

INPUT

POWER

SUPPLY

CIRCUITS

07921-001

OUT

CAP

A/D

CAP

OUT

UNIPOLAR

SINGLE-ENDED

INPUTS

SINGLE-ENDED

INPUT BUFFERING

Figure 1.

Summary of content (24 pages)

PAGE 1
Evaluation Board for the AD7265/AD7266 EVAL-AD7265/AD7266 FEATURES Full details on the AD7265 and the AD7266 are available in the device data sheets, which are available from Analog Devices, Inc., and should be consulted in conjunction with this data sheet when using the evaluation board.
PAGE 2
EVAL-AD7265/AD7266 TABLE OF CONTENTS Features .............................................................................................. 1 Operating with the EVAL-CED1Z ........................................... 13 General Description ......................................................................... 1 Evaluation Board Software ............................................................ 14 Functional Block Diagram ..............................................................
PAGE 3
EVAL-AD7265/AD7266 EVALUATION BOARD HARDWARE POWER SUPPLIES When using this evaluation board with the EVAL-CED1Z, all supplies are provided from the EVAL-CED1Z through the 96-way connector. When using the board as a standalone unit, external supplies must be provided. This evaluation board has the following power supply inputs: +12 V, −12 V, AVDD (+5 V), DVDD (+5 V), AGND, VDRIVE, and DGND. The +12 V supply is only required if the external AD780 voltage reference and op amps are to be used.
PAGE 4
EVAL-AD7265/AD7266 Link No. LK7 LK8 LK9 LK10 LK11 LK12 LK13 LK14 LK15 Description This link option selects the source of the VB1 analog input. In Position A, VB1 is supplied from the output of the unity gain buffer, U4-A, in which case a signal must be applied to the SVIN3 socket via J15. In Position B, VB1 is supplied from the positive output (V3+) of the single-ended-to-differential converter, U7-B, in which case a single-ended signal must be applied to V3 DIFF via Socket J20.
PAGE 5
EVAL-AD7265/AD7266 Link No. LK16 LK17 LK18 LK19 LK20 LK21 LK22 LK23 LK24 LK25 LK26 LK27 LK28 LK29 LK30 Description This link option sets the output reference voltage delivered by the AD780. When this link is inserted, the AD780 output voltage is set to +3.0 V. When this link is removed, the AD780 output voltage is set to +2.5 V. This link option selects the source of the VDRIVE supply for the AD7265/AD7266. In Position A, VDRIVE is supplied from the EVAL-CED1Z.
PAGE 6
EVAL-AD7265/AD7266 Link No. LK31 LK32 and LK34 LK33 LK35 LK36 LK37 and LK39 LK38 LK40 LK41 LK42 and LK44 LK43 LK45 LK46 LK47 and LK49 Description This link option adds a 50 Ω termination to AGND at the V1 DIFF socket (J17) for differential operation. This link is removed when using the single-ended-to-differential converter. When this link is inserted, a 50 Ω termination is added to the input signal applied to VI DIFF socket (J17).
PAGE 7
EVAL-AD7265/AD7266 Link No. LK48 LK50 LK51 LK52 LK53 LK54 LK55 LK56 LK57 Description This link option selects the common-mode voltage applied to U8-A, the AD8022 dual op amp configuration used to perform single-ended-to-differential conversion on the analog input. In Position A, an external common-mode voltage can be applied to U8-A via J23. In Position B, the +IN input is tied to AGND, in which case the AD8022 dual op amp is not used.
PAGE 8
EVAL-AD7265/AD7266 SETUP CONDITIONS Take care to ensure that all link positions are set according to the required operating mode before applying power and signals to the evaluation board. There are a few different modes in which to operate the evaluation board. Either the user can operate the board with the EVAL-CED1Z or it can be used as a standalone board. The board can accept differential and singleended analog input voltages.
PAGE 9
EVAL-AD7265/AD7266 Link No. LK33 LK36 LK37, LK39 LK38 LK41 LK42, LK44 LK43 LK46 LK47, LK49 LK48 LK50 LK51 LK52 LK53 LK56 LK57 Position B Closed Closed B Closed Closed B Closed Closed B B Open B Open A A Function The input to U5-A is tied to AGND because it is not used in single-ended mode. The input to U6-B is tied to AGND because it is not used in single-ended mode. The inputs to U6-A are tied to AGND because they are not used in single-ended mode.
PAGE 10
EVAL-AD7265/AD7266 Table 5. Link Positions for Differential Mode of Operation with a 0 V to 2 VREF Input Range When a Bipolar Single-Ended Signal Is Used with the Single-Ended-to-Differential Converter Link No. LK1 Position B LK2 B LK20 A LK21 LK31 LK32, LK34 LK33 B Open Closed C Function VA1 is supplied from the positive output (V1+) of the single-ended-to-differential converter, U5-B, in which case a single-ended signal must be applied to V1 DIFF via Socket J17.
PAGE 11
EVAL-AD7265/AD7266 SOCKETS CONNECTORS There are 25 SMB input/output sockets relevant to the operation of the AD7265/AD7266 on this evaluation board. All of these sockets are used for applying an externally generated signal to the evaluation board or for accessing an output signal from the AD7265/ AD7266. When operating the board with the EVAL-CED1Z board, the only external sockets necessary are those used to supply the analog input signals to the ADC (that is, VA1 to VA6 and VB1 to VB6).
PAGE 12
EVAL-AD7265/AD7266 INTERFACING THE EVALUATION BOARD TO THE EVAL-CED1Z 1 8 16 24 32 1 8 16 24 32 A B C 07921-002 Interfacing the EVAL-CED1Z board to the evaluation board is via a 96-way connector, J1. The pinout for the J1 connector is shown in Figure 2. Table 9 gives a description of the pins on the 96-way connector that are used to interface the EVAL-CED1Z to the EVAL-AD7265/AD7266. Figure 2. Pin Configuration for the 96-Way Connector, J1 Table 9.
PAGE 13
EVAL-AD7265/AD7266 OPERATING WITH THE EVAL-CED1Z The evaluation board can be operated in a standalone mode or it can be operated in conjunction with the EVAL-CED1Z. This evaluation board controller is available from Analog Devices under the order entry, EVAL-CED1Z. When interfacing the EVAL-AD7265/AD7266 directly to the EVAL-CED1Z board, all supplies and control signals to operate the AD7265/AD7266 board are provided by the EVAL-CED1Z.
PAGE 14
EVAL-AD7265/AD7266 EVALUATION BOARD SOFTWARE INSTALLING THE SOFTWARE SETTING UP THE EVAL-CED1Z The EVAL-AD7265/AD7266 evaluation kit includes self-installing software on a CD-ROM for controlling and evaluating the performance of the AD7265/AD7266 when it is operated with the EVAL-CED1Z board. The software is compatible with Windows® 2000/XP®. If the setup file does not run automatically, setup.exe can be run from the CD-ROM.
PAGE 15
EVAL-AD7265/AD7266 SOFTWARE OPERATION With the hardware set up, you can now use the software to control the EVAL-CED1Z and the AD7266 or AD7265 evaluation board. To launch the software, from the Analog Devices menu, select the AD7266/AD7265 submenu, and then click the AD7266/AD7265 icon. Figure 3 shows the window that appears when the software is run.
PAGE 16
EVAL-AD7265/AD7266 USING THE SOFTWARE samples taken, for example, the minimum/maximum position or velocity, the spread, the standard deviation, and the mean. Menu Bar The menu bar consists of the following menus: File, Edit, Operate, Tools, Window, and Help.
PAGE 17
EVAL-AD7265/AD7266 DNL Tab The DNL tab displays a DNL plot for the AD7266 or AD7265. This plot can be used to examine the dc performance of the ADC in conjunction with the INL plot. The Linearity Analysis section contains information on the maximum and minimum DNL error and the code at which this error occurred. TAKING SAMPLES To initiate a conversion and capture the sample data, you must click the Sample button or the Continuous button.
PAGE 18
EVAL-AD7265/AD7266 EVALUATION BOARD SCHEMATICS AND ARTWORK 07921-004 EVAL-AD7265/AD7266 schematics, silkscreen, and layout can be found in Figure 4 to Figure 9. Figure 4. AD7265/AD7266 Evaluation Board Circuit Diagram 1 Rev.
PAGE 19
07921-005 EVAL-AD7265/AD7266 Figure 5. AD7265/AD7266 Evaluation Board Circuit Diagram 2 Rev.
PAGE 20
07921-006 EVAL-AD7265/AD7266 Figure 6. AD7265/AD7266 Evaluation Board Circuit Diagram 3 Rev.
PAGE 21
07921-007 EVAL-AD7265/AD7266 07921-008 Figure 7. AD7265/AD7266 Evaluation Board PCB Layout—Component Side Figure 8. AD7265/AD7266 Evaluation Board PCB Layout—Solder Side Rev.
PAGE 22
07921-009 EVAL-AD7265/AD7266 Figure 9. AD7265/AD7266 Evaluation Board PCB Layout—Silkscreen Rev.
PAGE 23
EVAL-AD7265/AD7266 ORDERING INFORMATION BILL OF MATERIALS Table 11.