Page 1
Evaluation Board User Guide
One Technology Way • P. O . Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel : 781.329.4700 • Fax : 781.461.3113 • www.analog.com
UG-391
Evaluation Board for the AD5258 Digital Potentiometer
FEATURES
Full-featured in conjunction with low voltage digiPOT
motherboard (EVAL-MB-LV-SDZ)
Various test circuits
Various ac/dc input signals
PC control via a separately purchased system demonstration
platform (SDP-B or SDP-S)
PC software for control
PACKAGE CONTENTS
EVAL-AD5258DBZ board
EVAL-MB-LV-SDZ motherboard
CD that includes
Self-installing software that allows users to control the
board and exercise all functions of the device
Electronic version of the AD5258 data sheet
Electronic version of the UG-391 user guide
GENERAL DESCRIPTION
This user guide describes the evaluation board for evaluating the
AD5258, a single-channel, 64-position, nonvolatile memory
digital potentiometer in conjunction with the low voltage digiPOT
motherboard.
The AD5258 supports single-supply 2.7 V to 5.5 V operation,
making the device suited for battery-powered applications and
many other applications with superior low temperature
coefficient performance.
In addition, the AD5258 uses a versatile I
operates in fast mode, allowing speeds of up to 400 kHz. This
interface can be used to read back the wiper register and
EEPROM content.
The EVAL-MB-LV-SDZ can operate in single-supply mode and
incorporates an internal power supply from the USB.
Complete specifications for the AD5258 part can be found in
the AD5258 data sheet, which is available from Analog Devices,
Inc., and should be consulted in conjunction with this user
guide when using the evaluation board.
2
C serial interface that
EVAL-AD5258DBZ WITH MOTHERBOARD AND SDP-B
Figure 1. Digital Picture of Evaluation Board with Low Voltage DigiPOT Motherboard and System Demonstration Platform
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
10619-001
Rev. 0 | Page 1 of 16
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UG-391 Evaluation Board User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Package Contents .............................................................................. 1
General Description ......................................................................... 1
EVAL-AD5258DBZ with Motherboard and SDP-B .................... 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Power Supplies .............................................................................. 3
Test Circuits ................................................................................... 4
Signal Amplifier ............................................................................ 5
REVISION HISTORY
5/12—Revision 0: Initial Version
Evaluation Board Software ...............................................................6
Installing the Software ..................................................................6
Running the Software ...................................................................6
Software Operation .......................................................................7
Evaluation Board Schematics and Artwork ...................................8
Motherboard ..................................................................................8
Daughter Board .......................................................................... 12
Ordering Information .................................................................... 14
Bill of Materials ........................................................................... 14
Rev. 0 | Page 2 of 16
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Evaluation Board User Guide UG-391
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The EVAL-MB-LV-SDZ supports using single power supplies.
The evaluation board can be powered either from the SDP port
or externally by the J1 and J2 connectors, as described in Table 1.
All supplies are decoupled to ground using 10 μF tantalum and
0.1 μF ceramic capacitors.
Link Options
Several link and switch options are incorporated in the EVALMB-LV-SDZ board and should be set up before using the board.
Table 2 describes the positions of the links to control the
evaluation board by a PC, via the SDP board. The functions of
these link options are described in detail in Table 3 through
Tabl e 6.
Table 1. Maximum and Minimum Voltages of the Connectors
Connector
No. Label Voltage
J1-1 EXT VDD Analog positive power supply, VDD,
from 2.7 V to 5.5 V
J1-2 GND Analog ground
J2-1 VLOGIC Digital supply, from 2.7 V to VDD
J2-2 DGND Digital ground
Table 2. Link Options Setup for SDP Control (Default)
Link No. Option
A11 3.3 V
A12 AGND
A5 3.3 V
Table 3. Link Functions
Link No. Power Supply Options
A11 VDD This link selects one of the following as the positive power supply:
5 V (from SDP).
3.3 V (from SDP).
EXT VDD (external supply from the J1 connector).
A5 V
A12 GND AGND.
This link selects one of the following as the digital supply:
LOGI C
3.3 V (from SDP).
VLOGIC (external supply from the J2 connector).
Rev. 0 | Page 3 of 16
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UG-391 Evaluation Board User Guide
V
V
V
V
TEST CIRCUITS
The EVAL-AD5258DBZ and EVAL-MB-LV-SDZ incorporate
several test circuits to evaluate the performance of the AD5258.
DAC
The RDAC can be operated as a digital-to-analog converter
(DAC), as shown in Figure 2.
–
2
– V
2
AC+
SS
VDD
V
DD
SS
RDAC
BIAS
AGND
R34
A1
A
B
W
R35
W1
B1
BUF-W1
VOUT1
10619-002
Figure 2. DAC
RDAC
)(
VVV
B
A
(1)
64
and VB in Equation 1.
A
DD
V
DD
Table 5 shows the options available for the voltage references.
The output voltage is defined in Equation 1.
OUT
where:
RDAC is the code loaded in the RDAC register.
V
is the voltage applied to the A terminal (A9 link).
A
V
is the voltage applied to the B terminal (A10 link).
B
However, by using the R34 and R35 external resistors, the user
can reduce the voltage of the voltage references. In this case, use
the A1 and B1 test points to measure the voltage applied to the
A and B terminals and recalculate V
AC Signal Attenuation
The RDAC can be used to attenuate an ac signal, which must be
provided externally using the AC_INPUT connector, as shown
in Figure 3.
–
DD
1kHz
HPF
AC_INPUT
SS
2
AC+
AC
R34
A1
RDAC
A
B
V
– V
DD
BIAS
SS
2
AGND
W
R35
W1
B1
VOUT1
BUF-W1
Figure 3. AC Signal Attenuator
Depending on the voltage supply rails and the dc offset voltage
of the ac signal, various configurations can be used as described
in Table 4.
Table 4. AC Signal Attenuation Link Options
Link Options Conditions
A9 AC+ No dc offset voltage.
AC signal is outside the voltage supply rails
due to the dc offset voltage.
DC offset voltage ≠ VDD/21.
AC All other conditions.
A10 BIAS Use in conjunction with AC+ link1.
AGND All other conditions.
1
Recommended to ensure optimal total harmonic distortion (THD) performance.
The signal attenuation is defined in Equation 2.
nAttenuatio log20)dB( (2)
R
RR
WWB
ENDTOEND
where:
R
is the resistor between the W and B terminals.
WB
is the wiper resistance.
R
W
R
END-TO-END
is the end-to-end resistance value.
10619-003
Table 5. DAC Voltage References
Terminal Link (Daughter Board) Link (Motherboard) Options Description
A1 Switch B of A4 A9 AC+ Connects Terminal A1 to VDD /2
VDD Connects Terminal A1 to VDD
W1 Switch B of A3 BUF-W1 Connects Terminal W1 to an output buffer
B1 Switch B of A2 A10 BIAS Connects Terminal B1 to VDD/2
AGND Connects Terminal B1 to analog ground
A1 inserted Closes feedback loop of second op amp in the AD8618
Rev. 0 | Page 4 of 16
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Evaluation Board User Guide UG-391
SIGNAL AMPLIFIER
The RDAC can be operated as an inverting or noninverting
signal amplifier supporting linear or pseudologarithmic gains.
Table 6 shows the available configurations.
The noninverting amplifier with linear gain is shown in Figure 4,
and the gain is defined in Equation 3.
R
WB
G
where R
WB
The noninverting amplifier with pseudologarithmic gain is
shown in Figure 5, and the gain is defined in Equation 4.
G 1 (4)
where:
is the resistor between the W and B terminals.
R
WB
R
is the resistor between the A and W terminals.
AW
(3)
1
R38
is the resistor between the W and B terminals.
R41
W2
1.7kΩ
R38
2.7kΩ
WB
RDAC
10nF
B2
C1
VOUT2
R42
Figure 4. Linear Noninverting Amplifier
10619-004
V
IN
R
WB
R
AW
R41
1.7kΩ
V
R43
IN
W2
A2
AB
RDAC
C1
10nF
B2
W
R42
VOUT2
10619-005
Figure 5. Pseudologarithmic Noninverting Amplifier
R43 and R42 can be used to set the maximum and minimum
gain limits.
The inverting amplifier with linear gain is shown in Figure 6,
and the gain is defined in Equation 5.
Note that the input signal, V
R
WB
G
where R
WB
(5)
R38
is the resistor between the W and B terminals.
R38
2.7kΩ
V
IN
W2
RDAC
Figure 6. Linear Inverting Amplifier
, must be negative.
IN
R41
1.7kΩ
C1
10nF
WB
B2
R42
VOUT2
10619-006
Table 6. Amplifier Selection Link Options
Amplifier Gain Link (Daughter Board) Link (Motherboard) Label V
Range
IN
Noninverting Linear Switch A of A2, A3, and A4 A7 LIN 0 V to VDD
A6 N-INV
A1 not inserted A8 N-INV
Pseudologarithmic Switch A of A2, A3, and A4 A7 LOC 0 V to VDD
A6 N-INV
A1 not inserted A8 N-INV
Inverting Linear Switch A of A2, A3, and A4 A7 LIN −VDD to 0 V
A6 INV
A1 not inserted
A8 INV
Rev. 0 | Page 5 of 16
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UG-391 Evaluation Board User Guide
EVALUATION BOARD SOFTWARE
If the SDP board is not connected to the USB port when
INSTALLING THE SOFTWARE
The EVAL-AD5258DBZ kit includes evaluation board software
provided on a CD. The software is compatible with Windows®
XP, Windows Vista, and Windows 7 (both 32 bits and 64 bits).
Install the software before connecting the SDP board to the USB
port of the PC to ensure that the SDP board is recognized when
it is connected to the PC.
1.
Start the Windows operating system and insert the CD.
2.
The installation software opens automatically. If it does
not, run the
3.
After installation is completed, power up the evaluation
setup.exe file from the CD.
board as described in the Power Supplies section.
4.
Connect the EVAL-AD5258DBZ and EVAL-MB-LV-SDZ to
the SDP board and the SDP board to the PC using the USB
cable included in the evaluation kit.
5.
When the software detects the evaluation board, follow the
instructions that appear to finalize the installation.
RUNNING THE SOFTWARE
To run the program, do the following:
1.
Click Start > All Programs > Analog Devices > AD5258>
AD5258 Eval Board
>
Control Panel > Add or Remove Programs > AD5258
Eval Board.
. To uninstall the program, click Start
2.
the software is launched, a connectivity error displays (see
Figure 7). Simply connect the evaluation board to the USB
port of the PC, wait a few seconds, click
Rescan, and follow
the instructions.
Figure 7. Pop-Up Window Error
The main window of the EVAL-AD5258DBZ software then
opens, as shown in Figure 8.
10619-007
Figure 8. EVAL-AD5258DBZ Software Main Window
Rev. 0 | Page 6 of 16
10619-008
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Evaluation Board User Guide UG-391
SOFTWARE OPERATION
The main window of the EVAL-AD5258DBZ software is
divided into the following sections:
MANUAL DATA, RDAC
QUICK COMMANDS has the following options:
NOP places the device in no operation mode, reducing the
power consumption of the device.
STORE saves the value of the RDAC register in the
EEPROM memory.
RESTORE transfers the data of the EEPROM memory into
the RDAC register.
Protect/Unprotect allows you to protect or unprotect the
data writing.
MANUAL DATA has the following option:
A customized I
switching the scroll bars from 0 to 1 or from 1 to 0 as
desired and then clicking
In addition, the scroll bars are updated on each write
transfer, showing the command sent to the part.
, and MEMORY.
2
C data-word can be sent by manually
QUICK COMMANDS,
SEND DATA.
RDAC has the following option:
Enter a desired value into the text box to update the RDAC
registers and click
write/read operation is performed, and the value displayed
in this section is updated with the actual RDAC register
value. This function can be used to verify whether the
write operation was completed successfully.
MEMORY has the following option:
Clicking UPDATE reads the content of the EEPROM
memory and the tolerance of the resistance.
EXIT closes the program.
WRITE. When WRITE is clicked, a
Rev. 0 | Page 7 of 16
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UG-391 Evaluation Board User Guide
EVALUATION BOARD SCHEMATICS AND ARTWORK
MOTHERBOARD
10619-009
Figure 9. SDP Connector and Power Supply
Rev. 0 | Page 8 of 16
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Evaluation Board User Guide UG-391
10619-010
Figure 10. Schematic of Test Circuits
Rev. 0 | Page 9 of 16
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UG-391 Evaluation Board User Guide
10619-011
Figure 11. Schematic of Connectors to Daughter Board
Rev. 0 | Page 10 of 16
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Evaluation Board User Guide UG-391
10619-012
Figure 12. Component Side View
10619-013
Figure 13. Component Placement Drawing
10619-014
Figure 14. Layer 2 Side PCB Drawing
Rev. 0 | Page 11 of 16
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UG-391 Evaluation Board User Guide
DAUGHTER BOARD
10619-015
Figure 15. Schematic of Daughter Board
Rev. 0 | Page 12 of 16
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Evaluation Board User Guide UG-391
Figure 16. Component Side View
10619-016
10619-017
Figure 17. Component Placement Drawing
10619-018
Figure 18. Layer 2 Side PCB Drawing
Rev. 0 | Page 13 of 16
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UG-391 Evaluation Board User Guide
ORDERING INFORMATION
BILL OF MATERIALS
Table 7. Motherboard
Qty Reference Designator Description Supplier1/Part Number
3 BUF-3, BUF-4, BUF-W1 2-pin (0.1" pitch) header and shorting shunt FEC 1022247 and 150-411
3 A6, A7, A8 3-pin SIL header and shorting link FEC 1022248 and 150410
5 A5, A9, A10, A11, A12 6-pin (3 × 2), 0.1" header and shorting block FEC 148-535 and 150-411 (36-pin strip)
1 J1 3-pin terminal block (5 mm pitch) FEC 151790
2 J7, J8 4-pin SIL header FEC 1098035
1 J4 Receptacle, 0.6 mm, 120-way Digi-Key H1219-ND
1 J10 8-pin inline header; 100 mil centers FEC 1098038
1 J5 12-pin (2 × 6), 0.1" pitch header FEC 1098051
2 J2, J3 2-pin terminal block (5 mm pitch) FEC 151789
17
R1, R3, R6, R7, R8, R9, R10, R11, R12,
R13, R20, R22, R23, R34, R35, R42, R43
1 R2 SMD resistor, 2.2 kΩ, 0.01, 0603 FEC 1750676
1 R41 SMD resistor, 1.7 kΩ, 1% ,0603 FEC 1170811
1 R21 Resistor, surge, 1.6 Ω, 1%, 0603 FEC 1627674
1 R38 SMD resistor, 2.7 kΩ, 1%, 0603 FEC 1750678
1 R14 SMD resistor, 100 Ω, 1%, 0603 FEC 9330364
1 R4 SMD resistor, 1 kΩ, 0.01, 0603 FEC 9330380
3 R5, R25, R26 SMD resistor, 100 kΩ, 1%, 0603 FEC 9330402
5 R15, R16, R17, R18, R19 SMD resistor, 33 kΩ, 1%, 0603 FEC 9331034
1 C1 SMD capacitor, 100 nF, 10%, 0805 FEC 165-0863
8 C4, C9, C10, C11, C12, C17, C19, C21 SMD capacitor, 0.1 μF, ±10%, 0603 FEC 1759122
4 C2, C6, C7, C14 SMD capacitor, 0.1 μF, ±10%, 0603 FEC 301-9482
2 C8, C13 SMD capacitor, 10 μF, ±10% FEC 197-130
4 C18, C20, C22, C5 Capacitor, 10 μF, ±20% FEC 1190107
2 C3, C15 Capacitor, 470 nF, ±10%, 0603 FEC 1414037
1 C16 Capacitor, 4.7 nF, ±10%, 0603 FEC 1414642
1 C34 Capacitor, 4.7 nF, ±20% FEC 1432350
1 L2 Inductor, SMD, 600Z FEC 9526862
1 D1 Green SMD LED FEC 5790852
1 U1 Two-port level translating bus switch ADG3247BCPZ
1 U2 Dual op amp AD8652ARZ
1 U3 Precision low dropout voltage regulator ADP3303ARZ-3.3
1 U4 Operational amplifier AD8618ARZ
1 U5 I2C serial EEPROM, 64k, 2.5 V, MSOP-8 FEC 1331335
27
5
1
FEC refers to Farnell Electronic Component Distributors; Digi-Key refers to Digi-Key Corporation.
, RESET, SYNC, WP, A1, A2, A3,
LRDAC
A4, AGND, B1, VOUT_C1, VOUT_C2,
VOUT3, VOUT4, W1, W2, W3, W4
+3.3V, +5V, EXT_VDD, VLOGIC,
EXT_VSS
SMD resistor, 0 Ω, 0.01, 0603 FEC 9331662
Terminal, PCB, black, PK100, test point FEC 8731128
Terminal, PCB, red, PK100 FEC 8731144
Rev. 0 | Page 14 of 16
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Evaluation Board User Guide UG-391
Table 8. Daughter Board
Qty Reference Designator Description Supplier1/Part Number
U2
1
A1
1
A2, A3, A4
3
C2, C4
2
C1, C3
2
J1
1
J2
1
J3, J4
2
1
FEC refers to Farnell Electronic Component Distributors.
256-position digital potentiometer AD5258BRMZ10
2-pin (0.1" pitch) header and shorting shunt FEC 1022247 and 150-411
3-pin SIL header and shorting link FEC 1022248 and 150410
6.3 V tantalum capacitor (Case A), 10 μF, ±20% FEC 1190107
50 V, X7R ceramic capacitor, 0.1 μF, ±10% FEC 1759122
Header, 2.54 mm, PCB, 1 × 8-way FEC 1766172
12-pin (2 × 6), 0.1" pitch header FEC 1804099
5-pin SIL header FEC 1929016
Rev. 0 | Page 15 of 16
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UG-391 Evaluation Board User Guide
NOTES
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
ESD Caution
ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection
circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
Legal Terms and Conditions
By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the “Evaluation Board”), you are agreeing to be bound by the terms and conditions
set forth below (“Agreement”) unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you
have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you (“Customer”) and Analog Devices, Inc.
(“ADI”), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal,
temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided
for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional
limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term
“Third Party” includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including
ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may
not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to
promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any
occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board.
Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice
to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED “AS IS” AND ADI MAKES NO
WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED
TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL
PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER’S POSSESSION OR USE OF
THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI’S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE
AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable
United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of
Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby
submits to the pers onal jurisdiction and venu e of such courts. The United Nations Conventi on on Contracts for the Internation al Sale of Goods shall not apply to this Agreement and is expressly disclaimed.
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
UG10619-0-5/12(0)
Rev. 0 | Page 16 of 16
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