19-4171; Rev 0; 6/08
MAX5422 Evaluation Kit
General Description
The MAX5422 evaluation kit (EV kit) is an assembled
and tested PCB that evaluates the MAX5422 IC. The
MAX5422 is a 50kΩ 256-tap, nonvolatile, linear digital
potentiometer communicating over SPI™. The
MAX5422 features an internal nonvolatile EEPROM
used to store the potentiometer’s wiper position for ini-
tialization during power-up. The EEPROM is pro-
grammed through the SPI-compatible serial interface,
communicating at data rates up to 5MHz. The SPI sig-
nals can be transmitted through an on-board USB inter-
face circuit using a computer or a user-supplied SPI
bus along with PCB headers on the EV kit.
The EV kit also features Windows 2000/XP/Vista
®
-com-
patible software that provides a professional user inter-
face for exercising the MAX5422’s features. The program
is menu driven and offers a graphical user interface
(GUI) complete with buttons, track bars, and spin boxes.
The MAX5422 IC is powered from a 3.3V source gener-
ated from the EV kit’s USB interface circuit, or an exter-
nal user-supplied 2.7V to 5.25V DC power supply. The
MAX5422 section can be broken out from the EV kit,
allowing the MAX5422 to be attached to the user appli-
cations with minimal additional circuit area.
The EV kit can also evaluate the MAX5423 (100kΩ)
or MAX5424 (200kΩ) after IC replacement (U1). The
MAX5422 EV kit is shipped with a MAX5422ETA+
IC installed.
SPI is a trademark of Motorola, Inc.
Windows Vista is a registered trademark of Microsoft Corp.
Features
♦
Power-On Recall of Wiper Position from
Nonvolatile Memory
♦
2.7V to 5.25V Single-Supply Operation
♦
On-Board USB Interface Circuit for SPI-
Compatible Signals
♦
Proven USB-PC Connection for Power and
Control (USB Cable Included)
♦
Main Circuit Breakout Board
♦
PCB Headers for User-Supplied SPI-Compatible
Signals
♦
PCB Pads for Potentiometer Signals L, W, and H
♦
Evaluates the MAX5422ETA/MAX5423ETA/
MAX5424ETA in 3mm x 3mm x 0.8mm, 8-Pin
TDFN Package
♦
Windows 2000/XP/Vista (32-Bit)-Compatible
Software
♦
Fully Assembled and Tested
Evaluates: MAX5422/MAX5423/MAX5424
Ordering Information
PART
MAX5422EVKIT+
TYPE
EV Kit
+Denotes
lead-free and RoHS compliant.
Component List
DESIGNATION
C1, C3–C10,
C17, C21–C25
QTY
DESCRIPTION
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K or
TDK C1608X7R1C104K
10µF ±20%, 6.3V X5R ceramic
capacitors (0805)
Murata GRM21BR60J106M or
TDK C2012X5R0J106M
10pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H100J or
TDK C1608C0G1H100J
1µF ±10%, 10V X5R ceramic
capacitors (0603)
Murata GRM188R61A105K or
TDK C1608X5R1A105K
DESIGNATION
QTY
DESCRIPTION
22pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H220J or
TDK C1608C0G1H220J
3300pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H332K or
TDK C1608X7R1H332K
Green LED (0603)
Panasonic LNJ314G8TRA
Not installed, ferrite bead inductor
(0603)
2 x 6-pin headers
3-pin headers
2-pin header
15
C18, C19
2
C2, C13, C15
3
C20
1
D1
FB1
J1, J2
JU1, JU2
JU3
1
0
2
2
1
C11, C12
2
C14, C16, C26
3
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX5422 Evaluation Kit
Evaluates: MAX5422/MAX5423/MAX5424
Component List (continued)
DESIGNATION
P1
R1
R2
R3
R4
R5
R6, R7
QTY
1
1
1
1
1
1
2
DESCRIPTION
USB type-B right-angle male
receptacle
0Ω ±5% resistor (0603)
220Ω ±5% resistor (0603)
10kΩ ±5% resistor (0603)
2.2kΩ ±5% resistor (0603)
1.5kΩ ±5% resistor (0603)
27Ω ±5% resistors (0603)
256-tap digital potentiometer
(8 TDFN-EP*)
Maxim MAX5422ETA+
(Top Mark: AIJ)
32-bit microcontroller (68 QFN-EP*)
Maxim MAXQ2000-RAX+
93C46 type 3-wire EEPROM (8 SO)
UART-to-USB converter (32 TQFP)
3.3V regulator (5 SC70)
Maxim MAX8511EXK33+
(Top Mark: AEI)
2.5V regulator (5 SC70)
Maxim MAX8511EXK25+
(Top Mark: ADV)
Dual 1.8V to 5V level translator
(8 SSOP)
Single 1.8V to 5V level translator
(6 SOT23)
16MHz crystal
Hong Kong X’tals
SSM1600000E18FAF
FILE
INSTALL.EXE
MAX5422.EXE
FTD2XX.INF
UNINST.INI
USB_Driver_Help.PDF
SUPPLIER
Hong Kong
X'tals Ltd.
—
—
8
1
DESIGNATION
Y2
QTY
1
DESCRIPTION
6MHz crystal
Hong Kong X’tals
SSL6000000E18FAF
Shunts
PCB: MAX5422 Evaluation Kit+
*EP
= Exposed pad.
Component Suppliers
PHONE
WEBSITE
852-35112388 www.hongkongcrystal.com
U1
1
U2
U3
U4
U5
1
1
1
1
Murata Electronics
770-436-1300 www.murata-northamerica.com
North America, Inc.
Panasonic Corp. 800-344-2112 www.panasonic.com
TDK Corp.
847-803-6100 www.component.tdk.com
Note:
Indicate that you are using the MAX5422, MAX5423, or
MAX5424 when contacting these component suppliers.
U6
1
MAX5422 EV Kit Files
DESCRIPTION
Installs the EV kit files on the computer
Application program
USB driver file
Uninstalls the EV kit software
USB driver installation help file
U7
U8
1
1
Y1
1
Quick Start
Required Equipment
Before beginning, the following equipment is needed:
• MAX5422 EV kit (USB cable included)
• A user-supplied Windows 2000/XP/Vista PC with a
USB spare port
• One ohmmeter
Note:
In the following sections, software-related items
are identified by bolding. Text in
bold
refers to items
directly from the EV kit software. Text in
bold and under-
lined
refers to items from the Windows operating system.
Procedure
The MAX5422 EV kit is fully assembled and tested.
Follow the steps below to verify board operation:
1) Visit www.maxim-ic.com/evkitsoftware to download
the latest version of the EV kit software,
5422Rxx.ZIP. Save the EV kit software to a tempo-
rary folder and uncompress the ZIP file.
2) Install the EV kit software on the computer by
running the INSTALL.EXE program inside the
temporary folder. The program files are copied
and icons are created in the Windows
Start |
Programs
menu.
2
_______________________________________________________________________________________
MAX5422 Evaluation Kit
3) Verify that shunts are correctly installed on the follow-
ing jumpers and headers listed in the table below:
JUMPER
JU1
JU2
JU3
J1 (1-2)
J1 (3-4)
J1 (5-6)
J1 (7-8)
J1 (9-10)
J1 (11-12)
J2 (1-2)
J2 (3-4)
J2 (5-6)
J2 (7-8)
J2 (9-10)
J2 (11-12)
Not installed Shunt not required
Do not install shunts on these
Not installed pins; shunts will short the power
and signal lines to ground
SHUNT
POSITION
1-2
EV KIT FUNCTION
EV kit powered by the 3.3V gener-
ated from the USB interface circuit
H PCB pad is not connected to
Install on
one pin only VDD or the W PCB pad
Installed
Installed
Installed
Installed
Installed
Installed
L PCB pad is connected to GND
Connects 3.3V from USB interface
to MAX5422
Connects VDD from MAX5422 to
USB interface
Connects SCLK from USB
interface to MAX5422
Connects DIN from USB interface
to MAX5422
Connects
CS
from USB interface
to MAX5422
5) Connect the included USB cable from the PC to the
MAX5422 EV kit. A
Building Driver Database
win-
dow pops up in addition to a
New Hardware
Found
message when installing the USB driver for
the first time. If a window similar to the one
described above does not appear after 30s,
remove the USB cable from the board and recon-
nect it. Administrator privileges are required to
install the USB device driver on Windows
2000/XP/Vista.
6) Follow the directions of the
Add New Hardware
Wizard
to install the USB device driver. Choose the
Search for the best driver for your device
option.
Specify the location of the device driver to be
C:\Program Files\MAX5422
(default installation
directory) using the
Browse
button. During device
driver installation, Windows may show a warning
message indicating that the device driver Maxim
uses does not contain a digital signature. This is not
an error condition and it is safe to proceed with
installation. Refer to the USB_Driver_Help.PDF doc-
ument included with the software if there are prob-
lems during this step.
7) Start the MAX5422 EV kit software by opening its
icon in the
Start | Programs
menu.
8) Observe as the program automatically detects the
USB connection and starts the main program. After
successful connection, the EV kit software main
window appears in the upper-left corner of the win-
dow (Figure 1).
9) The MAX5422 EV kit is ready for additional testing.
See the
Detailed Description of Software
section for
more information on the software features.
Evaluates: MAX5422/MAX5423/MAX5424
Not installed Shunt not required
4) Connect the ohmmeter across the W and L PCB
pads.
_______________________________________________________________________________________
3
MAX5422 Evaluation Kit
Evaluates: MAX5422/MAX5423/MAX5424
Detailed Description of Software
Graphic User Interface (GUI) Panel
The MAX5422 EV kit software GUI shown in Figure 1 is
a Windows program that provides a convenient means
to control the MAX5422. Use the mouse or press the
tab key to navigate through the GUI controls. The cor-
rect SPI write operation is generated to update the
MAX5422 internal memory registers when any of these
controls are executed.
The software divides EV kit functions into logical blocks.
The
Interface
group box indicates the EV kit
Status
and the last write operation
Command Sent
and
Data
Sent
indicators. This data is used to confirm proper
device operation. The
Potentiometer Control
group
box changes the wiper position, stores the wiper posi-
tion from the volatile memory to the nonvolatile memory,
and recalls the wiper position from the nonvolatile mem-
ory to the volatile memory. The bottom status bar of
the main window provides the USB interface circuit
communication status. The
Factory Default
button pro-
grams the volatile and nonvolatile memory of the poten-
tiometer to midscale position.
Software Startup
Upon startup, the MAX5422 EV kit software automati-
cally searches for the USB interface circuit connection.
The MAX5422 EV kit enters the normal operating mode
when the USB connection is detected. The nonvolatile
memory wiper position is then transferred to the volatile
memory. Since the MAX5422 does not have read capa-
bility, all the spin boxes are set to question marks “??”
and the track bar is set to midscale. If the USB connec-
tion is not detected, the software prompts the user to
retry, exit the program, or enter the demo mode.
Demo Mode
The MAX5422 EV kit software enters the demo mode,
when the USB connection is not detected, by selecting
Cancel
on the
MAX5422 Evaluation Kit Interface
Circuit
popup window (Figure 2). The software can also
enter demo mode at any time by selecting
Options |
Demo Mode
from the menu bar in the main window.
When in demo mode, all software communication to the
EV kit circuit is disabled; however, most of the software
GUI is functional. Demo mode allows the user to evaluate
the software without hardware connectivity. To exit demo
mode, select
Options | Demo Mode
from the menu bar.
Figure 1. MAX5422 Evaluation Kit Software Main Window
Figure 2. MAX5422 Evaluation Kit Interface Circuit Popup Window
4
_______________________________________________________________________________________
MAX5422 Evaluation Kit
Wiper Position
The
Wiper Position
track bar in the
Potentiometer
Control
group box is used to change the wiper position
between the H and L end points. Use the computer
mouse or arrow keys to move the
Wiper Position
between the 256 position points. The wiper position can
also be changed by entering a numerical value
between 0 and 255 into the
H-W Volatile
or
L-W
Volatile
spin boxes, or by pressing the up or down
arrows of these spin boxes. A change in the
Wiper
Position
track bar, or
H-W Volatile/L-W Volatile
spin
boxes write to the volatile memory and the wiper posi-
tion is updated with the data sent. The data in the non-
volatile memory remains unchanged. The wiper position
is shown in the
H-W Volatile
and
L-W Volatile
spin
boxes. The
H-W Volatile
spin box shows the wiper
position with respect to the H end point and the
L-W
Volatile
spin box shows the wiper position with respect
to the L end point. During EV kit power-up, the wiper-
position data in the nonvolatile memory is transferred to
the volatile memory and the position of the wiper is
updated.
The H-W Volatile, L-W Volatile, H-W
Nonvolatile,
and
L-W Nonvolatile
spin boxes display
“??” after initializing the EV kit software because the
MAX5422 does not transmit data to the master.
end point. When writing to the nonvolatile memory, the
volatile memory and wiper position remain unchanged.
Evaluates: MAX5422/MAX5423/MAX5424
Volatile/Nonvolatile Data Transferring
The
Potentiometer Control
group box contains the
Store
and
Recall
buttons used to transfer data from the
volatile memory to the nonvolatile memory and the non-
volatile memory to the volatile memory, respectively.
When the
Store
button is pressed, the data present in
the volatile memory is transferred to the nonvolatile
memory. When the
Recall
button is pressed, the data
present in the nonvolatile memory is transferred to the
volatile memory, and the wiper position is updated. The
Store
and
Recall
buttons do not send any new data to
the device because the commands transferred data
already contained in the volatile or nonvolatile memory.
Factory Default
Pressing the
Factory Default
button resets the wiper
position in the MAX5422 volatile and nonvolatile memo-
ry to the factory-default position. The factory-default
wiper position is the midscale position.
Status Indicator
The
Status
indicator in the
Interface
group box dis-
plays
EV Kit Operational
when the MAX5422 EV kit
enters the normal operating mode after the USB con-
nection is detected. When USB connection is not
detected, or when the software enters the demo mode,
the
Status
indicator displays
Demo Mode.
Nonvolatile Programming
The
H-W Nonvolatile
and
L-W Nonvolatile
spin boxes
in the
Potentiometer Control
group box are used to
program the nonvolatile memory of the digital poten-
tiometers. The nonvolatile memory is changed by enter-
ing a numerical value between 0 and 255 into the
H-W
Nonvolatile
or
L-W Nonvolatile
spin boxes. The
H-W
Nonvolatile
spin box shows the wiper position with
respect to the H end point and the
L-W Nonvolatile
spin box shows the wiper position with respect to the L
Command Sent Indicator
The
Command Sent
indicator in the
Interface
group
box displays the last command sent from the master
(software) to the MAX5422. There are four commands
available in the MAX5422 IC. Table 1 describes the four
MAX5422 commands.
Table 1. MAX5422 SPI Command
MAX5422 REGISTER
COMMAND
BINARY
00000000
HEX
0x00
DESCRIPTION
SPI data is written to VREG
Wiper position updates with SPI data
No change to NVREG
SPI data is written to NVREG
No change to wiper position
No change to VREG
Copy VREG to NVREG
No change to wiper position
No change to VREG
Copy NVREG to VREG
Wiper position updates with NVREG
No change to NVREG
MAX5422 EV KIT
SOFTWARE CONTROL
H-W Volatile
L-W Volatile
H-W Nonvolatile
L-W Nonvolatile
VREG
NVREG
00010000
0x10
VREGxNVREG
00100000
0x20
Store
NVREGxVREG
00110000
0x30
Recall
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