Analog Devices EVAL-AD5254SDZ User manual

Evaluation Board User Guide
UG-236
One Technology Way •P. O. Box 9106 •Norwood, MA 02062-9106, U.S.A. •Tel: [phone] •Fax: [phone] •www.analog.com
Evaluation Board for the AD5254 Digital Potentiometer
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.Rev. 0 | Page 1 of 16
FEATURES
Full featured evaluation board for the AD5254
Several test circuits
Various ac/dc input signals
PC control via a separately purchased system development
platform (SDP)
PC control software
12 extra bytes in EEMEM for user-defined information
Resistor tolerance error stored in EEMEM
PACKAGE CONTENTS
EVAL-AD5254SDZ evaluation board
CD that includes
Self-installing software that allows users to control the
board and exercise all functions of the device
Electronic version of the AD5254 data sheet
Electronic version of the UG-236 document
GENERAL DESCRIPTION
This user guide describes the evaluation board for evaluating the
AD5254—a quad-channel, 256-position, nonvolatile memory
digital potentiometer. With versatile programmability, the AD5254
allows multiple modes of operation, including read/write access
in the RDAC and EEMEM registers, increment/decrement of
resistance, resistance changes in ±6 dB scales, wiper setting read-
back, and extra EEMEM for storing user-defined information,
such as memory data for other components or a lookup table.
The AD5254 supports a dual-supply ±2.25 V to ±2.75 V operation
and a single-supply 2.7 V to 5.5 V operation, making the device
suited for battery-powered applications and many other appli-
cations. In addition, the AD5254 uses a versatile I2C serial
interface that operates in fast mode, allowing speeds of up to
400 kbps and supporting the selection of up to four different I2C
addresses.
The EVAL -AD5254SDZ can operate in single-supply and dual-
supply mode and incorporates an internal power supply from
the USB.
Complete specifications for the AD5254 part can be found in
the AD5254 data sheet, which is available from Analog Devices,
Inc., and should be consulted in conjunction with this user
guide when using the evaluation board.
DIGITAL PICTURE OF EVALUATION BOARD WITH SYSTEM DEVELOPMENT PLATFORM
EVAL-AD5254SDZ
SYSTEM DEVELOPMENT
PLATFORM
09579-001
Figure 1.

UG-236 Evaluation Board User Guide
Rev. 0 | Page 2 of 16
TABLE OF CONTENTS
Features .............................................................................................. 1
Package Contents.............................................................................. 1
General Description ......................................................................... 1
Digital Picture of Evaluation Board with System Development
Platform ............................................................................................. 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Power Supplies .............................................................................. 3
Link Options ................................................................................. 3
Test Circuits ...................................................................................4
Evaluation Board Software...............................................................6
Installing the Software ..................................................................6
Running the Software ...................................................................6
Software Operation .......................................................................7
Evaluation Board Schematics and Artwork...................................8
Ordering Information.................................................................... 14
Bill of Materials........................................................................... 14
REVISION HISTORY
1/11—Revision 0: Initial Version

Evaluation Board User Guide UG-236
Rev. 0 | Page 3 of 16
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The EVAL -AD5254SDZ supports the use of single and dual
power supplies.
In single-supply mode, the evaluation board can be powered
either from the SDP port or externally by the J1-1, J1-2, and
J1-3 connectors, as described in Tabl e 1.
If dual-supply mode is required, the J1-1, J1-2, and J1-3 connectors
must provide the external power supply, as described in Tabl e 1.
All supplies are decoupled to ground using 10 µF tantalum and
0.1 µF ceramic capacitors.
Table 1. Maximum and Minimum Voltages of the Connectors
Connector No. Label Voltage
J1-1 EXT VDD Analog positive power supply, VDD.
For single-supply operation, it is
2.7 V to 5.5 V.
For dual-supply operation, it is
2.5 V to 2.75 V.
J1-2 GND Analog GND.
J1-3 EXT VSS Analog negative power supply, VSS.
For single-supply operation, it is 0 V.
For dual-supply operation, it is
−2.5 V to −2.75 V.
LINK OPTIONS
Several link and switch options are incorporated in the evalu-
ation 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, using the EVAL-AD5254SDZ in
single-supply mode. The functions of these link and switch
options are described in detail in Table 3 through Tabl e 6.
Table 2. Link Options Setup for SDP Control (Default)
Link No. Option
A25 3.3 V
A24 GND
Table 3. Link Functions
Link No. Power Supply Options
A25 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 J1-1 connector).
A24 VSS This link selects one of the following as the negative power supply:
GND (analog ground).
VDD VSS (external supply from the J1-3 connector).

UG-236 Evaluation Board User Guide
Rev. 0 | Page 4 of 16
TEST CIRCUITS
The EVAL-AD5254SDZ incorporates several test circuits to
evaluate the AD5254 performance.
DAC
RDAC0 can be operated as a digital-to-analog converter (DAC),
as shown in Figure 2.
09579-002
W1_BUF
A1
RDAC0
AC + DC
VDD
A0
B0 BUF-W1
VSS
GND
DC
2
V
DD
– V
SS
V
DD
2
V
DD
– V
SS
V
SS
R34
R35
W0
W1
B1
Figure 2. DAC
Table 4 shows the options available for the voltage references.
Table 4. DAC Voltage References
Terminal Link Options Description
A0 A20 AC + DC Connects Terminal A0 to
(VDD − VSS)/2
VDD Connects Terminal A0 to VDD
W0 BUF-W1 Connects Terminal W0 to an
output buffer
B0 A21 DC
Connects Terminal B0 to
(VDD − VSS)/2
VSS Connects Terminal B0 to VSS
GND
Connects Terminal B0 to
analog ground
The output voltage is defined in Equation 1.
256
)( RDAC0 VVV B0
A0
OUT  (1)
where:
RDAC0 is the code loaded in the RDAC0 register.
VA0 is the voltage applied to the A0 terminal (A20 link).
VB0 is the voltage applied to the B0 terminal (A21 link).
Using the R34 and R35 external resistors, you 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 A0 and B0
terminals and recalculate VA0 and VB0 in Equation 1.
AC Signal Attenuation
RDAC0 can be used to attenuate an ac signal, which must be
provided externally using the AC_INPUT connector, as shown
in Figure 3.
W1_BUF
A1
RDAC0
AC + DC
A
C_INPUT
AC
A0
B0 BUF-W1
GND
2
V
DD
–
V
SS
V
SS
R34
R35
W0
W1
B1
1µF
R36
0
9579-003
DC
VSS
2
V
DD
– V
SS
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 5.
Table 5. AC Signal Attenuation Link Options
Voltage
Supply
Maximum
AC Signal
Amplitude Link Options Conditions
Single VDD A20 AC + DC 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
A21 DC
Use in conjunction
with AC + DC link
GND All other conditions
Dual VDD/VSS A20 AC + DC AC signal is outside
the voltage supply
rails due to the
dc offset voltage
DC offset voltage
≠ 0 V1
AC All other conditions
A21 GND
Use in conjunction
with AC + DC link
VSS All other conditions
1Recommended to ensure optimal total harmonic distortion (THD) performance.
The signal attenuation is defined in Equation 2.









 ENDTOEND
WWB
R
RR
nAttenuatio 0
log20)dB( (2)
where:
RWB0 is the resistor between the W0 and B0 terminals.
RWis the wiper resistance.
REND-TO-END is the end-to-end resistance value.

Evaluation Board User Guide UG-236
Rev. 0 | Page 5 of 16
In addition, R36 can be used to achieve a pseudologarithmic
attenuation. To do so, adjust the R36 resistor until a desirable
transfer function is found.
Signal Amplifier
RDAC1 can be operated as an inverting or noninverting signal
amplifier supporting linear or pseudologarithmic gains. Table 6
shows the available configurations.
Table 6. Amplifier Selection Link Options
Amplifier Gain Link Label
Noninverting Linear A27 LINEAR
A29 NON-INVERTING
A30 NON- INVERTING
Pseudologarithmic A27 PSEUDOLOG
A29 NON- INVERTING
A30 NON- INVERTING
Inverting Linear A27 LINEAR
A29 INVERTING
A30 INVERTING
Pseudologarithmic A27 PSEUDOLOG
A29 INVERTING
A30 INVERTING
The noninverting amplifier with linear gain is shown in Figure 4,
and the gain is defined in Equation 3.
R38
R
GWB1 += 1(3)
where RWB1is the resistor between the W1 and B1 terminals.
VIN
RDAC1
B1 R42
W1 B2
W2
V
OUT
OAVOUT
C1
10nF
R41
1.7kΩ
R38
2.7kΩ
09579-004
Figure 4. Linear Noninverting Amplifier
The noninverting amplifier with pseudologarithmic gain is
shown in Figure 5, and the gain is defined in Equation 4.
AW1
WB1
R
R
G+=1
(4)
where:
RWB1is the resistor between the W1 and B1 terminals.
RAW 1is the resistor between the A1 and W1 terminals.
VIN
RDAC1
B1A1 R42
W1 B2
W2
VOUT
OAVOUT
A2
C1
10nF
R41
1.7kΩ
R43
09579-005
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.
R38
R
GWB1
−= (5)
where RWB1is the resistor between the W1 and B1 terminals.
VIN
RDAC1
B1 R42
W1 B2
W2
VOUT
OAVOUT
C1
10nF
R41
1.7kΩ
R38
2.7kΩ
09579-006
Figure 6. Linear Inverting Amplifier
The inverting amplifier with pseudologarithmic gain is shown
in Figure 7, and the gain is defined in Equation 6.
AW1
WB1
R
R
G−=
(6)
where:
RWB1is the resistor between the W1 and B1 terminals.
RAW 1is the resistor between the A1 and W1 terminals.
V
IN
RDAC1
B1A1 R42
W1 B2
W2
V
OUT
OAVOUT
A2
C1
10nF
R41
1.7kΩ
R43
09579-007
Figure 7. Pseudologarithmic Inverting Amplifier
R43 and R42 can be used to set the maximum and minimum
gain limits.
Output Buffers
RDAC2 and RDAC3 can be connected to an output buffer as
shown Figure 8 and Figure 9.
09579-008
VOUT3
RDAC2
A2
B2 BUF_3
A3
B3
W2
W3
Figure 8. RDAC2
09579-009
VOUT4
RDAC3
A3
B3 BUF_4
A4
B4
W3
W4
Figure 9. RDAC3

UG-236 Evaluation Board User Guide
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EVALUATION BOARD SOFTWARE
INSTALLING THE SOFTWARE
The EVAL-AD5254SDZ evaluation kit includes evaluation
board software provided on a CD. The software is compatible
with Windows® XP, Windows Vista, and Windows 7 (both 32
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 must open automatically. If it
does not, run the setup.exe file from the CD.
3. After installation is completed, power up the evaluation
board as described in the Power Supplies section.
4. Plug the EVAL-AD5254SDZ into the SDP board and the SDP
board into the PC using the USB cable included in the box.
5. When the software detects the evaluation board, follow the
instructions that appear to finalize the installation.
To uninstall the program, click Start > Control Panel > Add or
Remove Programs > AD5254 Eval Board.
RUNNING THE SOFTWARE
To r un t he evaluation board software, do the following:
1. Click Start > All Programs > Analog Devices > AD5254
>AD5254 Eval Board.
2. If the SDP board is not connected to the USB port when
the software is launched, a connectivity error is displayed
(see Figure 10). Connect the evaluation board to the USB
port of the PC, wait a few seconds, click Rescan, and follow
the instructions.
09579-010
Figure 10. Pop-Up Window Error
The main window of the E VAL -AD5254SDZ evaluation
software then opens, as shown in Figure 11.
09579-011
Figure 11. EVAL-AD5254SDZ Evaluation Board Software Main Window

Evaluation Board User Guide UG-236
Rev. 0 | Page 7 of 16
SOFTWARE OPERATION
The main window of the E VA L -AD5254SDZ software is
divided into the following sections: QUICK COMMANDS,
REGISTER ACCESS, WP, TOLERANCE, and MEMORY. The
features of the main window are as follows:
•The QUICK COMMANDSsection allows you to send the
AD5254 quick commands directly to the AD5254.
•The REGISTER ACCESS section can be used to update
the RDAC registers by typing a value into a window and
clicking WRITE. Alternatively, you can send a customized
I2C data word by manually switching the scroll bars from 0
to 1 or from 1 to 0, as desired, and then clicking SEND
DATA. When WRITE is clicked or a quick command is
executed, a write-read operation is performed, and the
values displayed in this section are updated with the actual
RDAC register values. This function can be used to verify
whether the write operation was completed successfully.
The scroll bars are updated upon each write transfer.
•The WP section enables or disables the AD5254 WP pin.
•The TOLERANCE section displays the stored tolerance of
each internal resistor.
•The MEMORY section displays the data stored in the
memory block. The data can be updated by switching the
scroll bar from READ to WRITE, updating a particular
window value, clicking UPDATE ALL or UPDATE
SINGLE, and selecting the memory location to write.
•Clicking EXIT closes the program but does not reset the part.

UG-236 Evaluation Board User Guide
Rev. 0 | Page 8 of 16
EVALUATION BOARD SCHEMATICS AND ARTWORK
09579-019
MULTICHANNEL
I2C
SPI
U/D
0x5E
0x5E
0x58 0x5A
1AGND2
2B2 3A2 7A4 8W4
9
DGND
10
SHDN
11
SYNC
12
DIN
5AGND4 6B4 4W2
21 AGND1
19 A3
13
SDO
14
SCLK
15
RESET
16
VDD
17 AGND3
18 W3 24 B1 22 W1
23 A1 20 B3
U6 AD8403
1W1
2B1 3A1 7B2 8A2 9
SDA
10
VSS
11 A3 12 B3 5
WP
6W2
4
AD0
19 W4 13 W3
14
SCL
15
DGND
16
AD1
17 A4
18 B4
20
VDD
U7 AD5254
1
NC
2
NC
3
GND
7
SHDN
8
DIN
9
SCLK
10
SDO
11
VSS
12
NC
5
RESET
6
VDD
4
SYNC
21 B2 19 A2 13 B3 14 W3
15 A3 16 B1 17 W1
18 A1 24 B4 22 A4 23 W4 20 W2
U8 AD5204
4
GND
5
VDD
6
SCL
8A2
7
SDA
1B1
2A1
3W2 9B2
10 W1
U1
AD5243
4
GND
5
VDD
6
SCLK
8
SYNC 7
DIN
1B1 2A1 3W2 9B2
10 W1
U2
AD5162
4
GND
5
VDD
6
SCL
8A2
7
SDA
1B1
2A1 3W2
9B2
10 W1
U3
AD5172_SOCKET
1
O1
2
SCLK 3
DIN
7A1 8W1 9B1
10 A2 11 W2 12 B2
5
GND 6
VSS
4
SDO
19
VDD
13 B3
14 W3
15 A3 16 B4 17 W4 18 A4 20
WP
21
RESET
22
SYNC
23
RDY
24
O2
U4 AD5233
4
VSS
5W2
6A2
8
GND
7B2 1B1 2A1 3W1
9
MODE 10
DACSEL 11
U/D 12
CLK 13
CS
14
VDD
U5
AD5222
4W1 5B1 6A1
8
VSS
7
SDA
1
VDD
2
AD0
3
WP
9
SCL
10
DGND
11
AD1
12 A3
13 B3
14 W3
U9
AD5252
4
GND 5
VSS
6A1 8B1
7W1
1
SCLK 2
DIN 3
SDO
9B2
10 W2 11 A2
12
VDD
13
WP 14
RESET
15
SYNC
16
RDY
U10
AD5232
4
GND 5
VSS
6A1
8B1
7W1
1
SCLK 2
DIN 3
SDO
9B2
10 W2 11 A2
12
VDD
13
WP 14
RESET
15
SYNC
16
RDY
U11
AD5235
4
GND 5
VSS
6V1
8B1
7W1
1
SCLK 2
DIN 3
SDO
9B2
10 W2
11 V2
12
VDD
13
WP 14
RESET
15
SYNC
16
RDY
U12
ADN2850
A1
W1-1
B1 A2
W2-1
B2 A3
W3-1
B3 A4
W4-1
B4
SHDN
RESET
SCLK
SDO DIN SYNC-1
A1
W1-8
B1 A2
W2-8
B2 A3
W3-8
B3 A4
W4-8
B4
SDA SCL WP
A1
W1-5
B1 A2
W2-5
B2
RDY
SDO DIN SCLK SYNC-5
WP
RESET
VDD
VDD
VSS
VSS
VDD
A1
W1-4
B1
W2-4
B2
SYNC-4
DIN SCLK
VDD
A1
W1-2
B1 A2
W2-2
B2 A3
W3-2
B3 A4
W4-2
B4
SYNC-2
SCLK DIN SDO RESET
SHDN
VDD
VSS
A1
W1-3
B1 A2
W2-3
B2 A3
W3-3
B3 A4
W4-3
B4
O1 O2 RDY SDO SCLK
DIN SYNC-3
RESET
WP
VDD
VSS
W1-6
B1
W2-6
B2 V1
V2
RDY
SDO DIN SCLK SYNC-6
WP
RESET
VDD
VSS
A1
W1-9
B1 A2
W2-9
B2
A1
W1-7
B1 A2
W2-7
B2
RDY
SDO DIN SCLK SYNC-7
WP
RESET
VDD
VSS
VDD
SCL
SDA
WP
VSS
VDD
A1
W1-10
B1 A2
W2-10
B2
SDA SCL
A1
W1-11
B1 A2
W2-11
B2
SDA
SCL
VDD VDD
A1
W1-12
B1 A2
W2-12
B2
CS
CLK U/D
DACSEL
MODE
VDD
VSS
Figure 12. Schematic of Multiboard Digital Potentiometers

Evaluation Board User Guide UG-236
Rev. 0 | Page 9 of 16
VDD
DAC + FLOATING DAC + BW
PSEUDOLOGATTENUATOR
B1
AC
AD8403-1
AD5204-1
AD5233-1
AD5162-1
AD5232-1
ADN2850-1
AD5235-1
AD5254-1
AD5252-1
AD5172
AD5243-1
W1
AD5222-1
+
-1
2
3U14-A
AD8618ARZ
BUF-W1 W1_BUF
R34
R35
R39
R40
AC_INPUT C3
A1
B1
R36
A
B
C
A20
A
B
C
A21
R3
R4
3+
2-
1
U15-A
AD8652AR
5+
6-7
U15-B
AD8652AR
8
V+
4
V-
U15-C
W1-1
W1-2
W1-3
W1-4
W1-5
W1-6
W1-7
W1-8
W1-9
W1-10
W1-11
W1
W1-12
VDD
VSS
A1
B1
VSS
VDD
VSS
VDD
VSS
09579-020
AC + DC
Figure 13. Schematic of Multiboard RDAC0 Circuits
09579-021
INVERTINGANDNON-INVERTINGW ITHLINEARANDPSEUDO-LOGGAIN
DIGIPOT
PSEUDOLOG
LINEAR
NON-INVERTING
INVERTING
NON-INVERTING
INVERTING
CIRCUIT CONNECTION
VIN
GND
+
-
7
6
5U14-B
AD8618ARZ
AD8403 -2
AD5204 -2
AD5233 -2
AD5162 -2
AD5232 -2
ADN2850 -2
AD5235 -2
AD5254 -2
AD5252 -2
AD5172 -2
AD5243 -2
AD5322 -2
W2
VOUT
R38
J2-1
J2-2
R41
R42
R43
B2
A2
OAVOUT
C1
BA
A29
BA
A27
BA
A30
W2-1
W2-2
W2-3
W2-4
W2-5
W2-6
W2-7
W2-8
W2-9
W2-10
W2-11
W2-12
W2
A2
B2W2
Figure 14. Schematic of Multiboard RDAC1 Circuits

UG-236 Evaluation Board User Guide
Rev. 0 | Page 10 of 16
09579-017
POWER-SUPPLIES
EXT VDD
+5V
+3.3V
GND
EXT VSS
GND
CHANNELS 3 AND 4 POWER-SUPPLY
DIGITAL PINS CURRENT MONITOR
+
C24 10uF C25
0.1uF
C26 0.1uF
+
C27 10uF
J1-1
J1-2 J1-3
A
B C
A25
A B
A24
+ -14
13 12 U14-D
AD8618ARZ
AD8403-4 AD5204-4 AD5233-4 AD5254-4
+ -8
9
10 U14-C
AD8618ARZ
AD8403-3 AD5204-3 AD5233-3 AD5254-3
BUF-4
BUF-3
A4
VOUT4
B4
A3
VOUT3
B3
W4
W3
O2 O1
V2 V1
C2 0.1uF
C4 0.1uF
VSS
VDD
+3.3V +5V
W4-1 W4-2 W4-3 W4-8
W3-1 W3-2 W3-3 W3-8
B4
A3
B3
A4
O1
O2
V1
V2
Figure 15. Schematic of AD5254 Power Supplies and Other Channels