MAXIM MAX5422_08

19-4171; Rev 0; 6/08
MAX5422 Evaluation Kit
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 initialization during power-up. The EEPROM is programmed through the SPI-compatible serial interface,
communicating at data rates up to 5MHz. The SPI signals can be transmitted through an on-board USB interface 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®-compatible software that provides a professional user interface 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 generated from the EV kit’s USB interface circuit, or an external 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 applications 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.
Features
♦ Power-On Recall of Wiper Position from
Nonvolatile Memory
♦ 2.7V to 5.25V Single-Supply Operation
♦ On-Board USB Interface Circuit for SPICompatible 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
Ordering Information
PART
TYPE
MAX5422EVKIT+
EV Kit
+Denotes lead-free and RoHS compliant.
SPI is a trademark of Motorola, Inc.
Windows Vista is a registered trademark of Microsoft Corp.
Component List
DESIGNATION
C1, C3–C10,
C17, C21–C25
C2, C13, C15
C11, C12
C14, C16, C26
QTY
DESCRIPTION
15
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K or
TDK C1608X7R1C104K
3
10µF ±20%, 6.3V X5R ceramic
capacitors (0805)
Murata GRM21BR60J106M or
TDK C2012X5R0J106M
2
10pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H100J or
TDK C1608C0G1H100J
3
1µF ±10%, 10V X5R ceramic
capacitors (0603)
Murata GRM188R61A105K or
TDK C1608X5R1A105K
DESIGNATION
QTY
DESCRIPTION
2
22pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H220J or
TDK C1608C0G1H220J
C20
1
3300pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H332K or
TDK C1608X7R1H332K
D1
1
Green LED (0603)
Panasonic LNJ314G8TRA
FB1
0
Not installed, ferrite bead inductor
(0603)
J1, J2
2
2 x 6-pin headers
JU1, JU2
2
3-pin headers
JU3
1
2-pin header
C18, C19
________________________________________________________________ Maxim Integrated Products
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.
1
Evaluates: MAX5422/MAX5423/MAX5424
General Description
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
Component List (continued)
DESIGNATION
P1
QTY
1
DESCRIPTION
USB type-B right-angle male
receptacle
DESCRIPTION
Y2
1
6MHz crystal
Hong Kong X’tals
SSL6000000E18FAF
1
0Ω ±5% resistor (0603)
R2
1
220Ω ±5% resistor (0603)
—
8
Shunts
—
1
PCB: MAX5422 Evaluation Kit+
R3
1
10kΩ ±5% resistor (0603)
R4
1
2.2kΩ ±5% resistor (0603)
R5
1
1.5kΩ ±5% resistor (0603)
R6, R7
2
27Ω ±5% resistors (0603)
1
256-tap digital potentiometer
(8 TDFN-EP*)
Maxim MAX5422ETA+
(Top Mark: AIJ)
Hong Kong
X'tals Ltd.
*EP = Exposed pad.
Component Suppliers
SUPPLIER
PHONE
WEBSITE
852-35112388 www.hongkongcrystal.com
U2
1
32-bit microcontroller (68 QFN-EP*)
Maxim MAXQ2000-RAX+
Murata Electronics
770-436-1300 www.murata-northamerica.com
North America, Inc.
U3
1
93C46 type 3-wire EEPROM (8 SO)
Panasonic Corp. 800-344-2112 www.panasonic.com
U4
1
UART-to-USB converter (32 TQFP)
TDK Corp.
U5
1
3.3V regulator (5 SC70)
Maxim MAX8511EXK33+
(Top Mark: AEI)
Note: Indicate that you are using the MAX5422, MAX5423, or
MAX5424 when contacting these component suppliers.
U6
1
2.5V regulator (5 SC70)
Maxim MAX8511EXK25+
(Top Mark: ADV)
U7
1
Dual 1.8V to 5V level translator
(8 SSOP)
U8
1
Single 1.8V to 5V level translator
(6 SOT23)
1
16MHz crystal
Hong Kong X’tals
SSM1600000E18FAF
Y1
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 underlined refers to items from the Windows operating system.
2
QTY
R1
U1
•
DESIGNATION
847-803-6100 www.component.tdk.com
MAX5422 EV Kit Files
FILE
DESCRIPTION
INSTALL.EXE
Installs the EV kit files on the computer
MAX5422.EXE
Application program
FTD2XX.INF
USB driver file
UNINST.INI
Uninstalls the EV kit software
USB_Driver_Help.PDF
USB driver installation help file
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 temporary 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.
_______________________________________________________________________________________
MAX5422 Evaluation Kit
JUMPER
SHUNT
POSITION
EV KIT FUNCTION
JU1
1-2
EV kit powered by the 3.3V generated from the USB interface circuit
JU2
JU3
H PCB pad is not connected to
Install on
one pin only VDD or the W PCB pad
Installed
L PCB pad is connected to GND
J1 (1-2)
Installed
Connects 3.3V from USB interface
to MAX5422
J1 (3-4)
Installed
Connects VDD from MAX5422 to
USB interface
J1 (5-6)
Installed
Connects SCLK from USB
interface to MAX5422
J1 (7-8)
Installed
Connects DIN from USB interface
to MAX5422
J1 (9-10)
Installed
Connects CS from USB interface
to MAX5422
J1 (11-12)
Not installed Shunt not required
J2 (1-2)
J2 (3-4)
J2 (5-6)
J2 (7-8)
Do not install shunts on these
Not installed pins; shunts will short the power
and signal lines to ground
J2 (9-10)
J2 (11-12)
Not installed Shunt not required
4) Connect the ohmmeter across the W and L PCB
pads.
5) Connect the included USB cable from the PC to the
MAX5422 EV kit. A Building Driver Database window 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 reconnect 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 document included with the software if there are problems 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 window (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.
_______________________________________________________________________________________
3
Evaluates: MAX5422/MAX5423/MAX5424
3) Verify that shunts are correctly installed on the following jumpers and headers listed in the table below:
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
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 correct 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 position from the volatile memory to the nonvolatile memory,
and recalls the wiper position from the nonvolatile memory to the volatile memory. The bottom status bar of
the main window provides the USB interface circuit
communication status. The Factory Default button programs the volatile and nonvolatile memory of the potentiometer to midscale position.
Software Startup
Upon startup, the MAX5422 EV kit software automatically 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 capability, all the spin boxes are set to question marks “??”
and the track bar is set to midscale. If the USB connection is not detected, the software prompts the user to
retry, exit the program, or enter the demo mode.
Demo Mode
Figure 1. MAX5422 Evaluation Kit Software Main Window
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 2. MAX5422 Evaluation Kit Interface Circuit Popup Window
4
_______________________________________________________________________________________
MAX5422 Evaluation Kit
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 potentiometers. The nonvolatile memory is changed by entering 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
end point. When writing to the nonvolatile memory, the
volatile memory and wiper position remain unchanged.
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 nonvolatile 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 memory to the factory-default position. The factory-default
wiper position is the midscale position.
Status Indicator
The Status indicator in the Interface group box displays EV Kit Operational when the MAX5422 EV kit
enters the normal operating mode after the USB connection is detected. When USB connection is not
detected, or when the software enters the demo mode,
the Status indicator displays Demo Mode.
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
DESCRIPTION
MAX5422 EV KIT
SOFTWARE CONTROL
BINARY
HEX
VREG
00000000
0x00
SPI data is written to VREG
Wiper position updates with SPI data
No change to NVREG
NVREG
00010000
0x10
SPI data is written to NVREG
No change to wiper position
No change to VREG
H-W Nonvolatile
L-W Nonvolatile
VREGxNVREG
00100000
0x20
Copy VREG to NVREG
No change to wiper position
No change to VREG
Store
NVREGxVREG
00110000
0x30
Copy NVREG to VREG
Wiper position updates with NVREG
No change to NVREG
Recall
H-W Volatile
L-W Volatile
_______________________________________________________________________________________
5
Evaluates: MAX5422/MAX5423/MAX5424
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 position is updated with the data sent. The data in the nonvolatile 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 wiperposition 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.
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
Data Sent Indicator
The Data Sent indicator in the Interface group box displays the last data sent from the master (software) to
the MAX5422. The Data Sent indicator displays the last
data sent for the write to VREG (0x00) command and
the write to NVREG (0x10) command. Since the
VREGxNVREG (0x20) and the NVREGxVREG (0x30)
commands do not send any new data to the MAX5422,
the Data Sent indicator is hidden when these two commands are executed.
The MAX5422 IC uses an 8-bit (MSBs, D7–D0) data
byte to set the wiper position. Refer to the MAX5422/
MAX5423/MAX5424 IC data sheet for additional
information.
Keyboard Navigation
Press the Tab key to select each GUI control. The
selected control is indicated by a dotted outline. Using
Shift + Tab moves the selection to the previously selected control. Buttons respond to the keyboard’s space
bar and some controls respond to the keyboard’s up
and down arrow keys. Activate the program’s menu bar
by pressing the F10 key and then press the letter of the
desired menu item. Most menu items have one letter
underlined, indicating their shortcut key.
When a number is entered into the volatile or nonvolatile text boxes, it can be sent to the device by
pressing the Enter key. It is also sent when Tab or Shift
+ Tab is pressed.
Simple SPI Commands
There are two methods for communicating with the
MAX5422 EV kit, through the normal user-interface
panel (Figure 1) or through the SPI commands available by selecting the 3-Wire Interface (Figure 3) utility
from the main program’s Options | Interface
(Advanced Users) main menu. A window is displayed
that allows SPI send/receive data operations.
6
The Connection group box allows the user to define the
hardware connections of the interface. For the
MAX5422 EV kit, select K10 from the Clock (SCK)
(SCLK) drop-down list, K12 from the Data from master
to slave (MOSI) (DIN) drop-down list, K11 from the
Data from slave to master (MISO) (DOUT) drop-down
list, K9 from the Chip-select (CS) for data framing
drop-down list, and uncheck the Use standard connections for high-speed SPI checkbox (see Figure 3).
The Configuration group box allows the user to configure the logic level and data rate. For the MAX5422 EV
kit, check the Send & Receive MSB first and the
CPOL=1 (clock idle high) checkboxes (see Figure 3).
The Send and Receive Data group box allows the user
to send and receive data to and from the MAX5422.
The Data bytes to be written edit box is data to be
sent from the master (microcontroller) to the device
(MAX5422). Eight-bit hexadecimal numbers should be
comma delimited. Press the Send Now button to transmit the data from the master to the device. Data
appearing in the Data bytes received edit box is data
read from the device. The Data bytes received edit
box in the MAX5422 EV kit software always shows a
default value of 0xFF since the MAX5422 does not
send data back to the master.
Note: The SPI dialog boxes accept numeric data in
hexadecimal format. Hexadecimal numbers must be
prefixed by $ or 0x. See Figure 3 for an example of
this tool. Figure 3 shows a simple SPI write-byte operation using the included 3-wire interface diagnostics
tool. In this example, the software is sending a command 0x00 (write to volatile memory), and a data
0x7F. The data sequence sets the MAX5422 wiper
position to 128.
_______________________________________________________________________________________
MAX5422 Evaluation Kit
General Troubleshooting
Problem: Software reports it cannot find the interface circuit.
• Is the interface circuit power LED lit?
• Is the USB cable connected?
•
•
Has Windows plug-and-play detected the board?
Bring up Control Panel->System->Device
Manager, and look at what device nodes are indicated for USB. If there is an Unknown device node
attached to the USB, delete it—this forces plugand-play to try again.
Are jumper JU1 and headers J1 and J2 properly
configured for USB operation? See Tables 2 and 3.
Detailed Description of Hardware
The MAX5422 EV kit is an assembled and tested PCB
that evaluates the MAX5422 256-tap, nonvolatile, linear
digital potentiometer. The MAX5422 has an end-to-end
resistance of 50kΩ and the wiper can be programmed
to one of 256 tap positions. The MAX5422 features an
internal, nonvolatile memory (EEPROM) used to store
the wiper position for initialization during power-up. The
MAX5422 EV kit provides an on-board SPI-compatible
serial interface to program the MAX5422.
The EV kit uses a MAX5422 IC in an 8-pin TDFN package on a proven two-layer PCB design. The MAX5422
EV kit provides two options to power the MAX5422 IC. It
can operate from the 3.3V supply generated from the
USB interface circuit, or from a user-supplied 2.7V to
5.25V external DC power supply. The logic level translators (U7, U8) provide proper SPI-interface operation
when using a 2.7V to 5.25V external power supply.
_______________________________________________________________________________________
7
Evaluates: MAX5422/MAX5423/MAX5424
Figure 3. Simple Low-Level 3-Wire Interface
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
The MAX5422 main circuit area consists of the
MAX5422 IC U1, decoupling capacitors C25 and C26,
jumpers JU1, JU2, and JU3, header J2, and PCB pads
H, W, L, VCC, and GND. The MAX5422 main circuit
PCB section is less than 1.2in x 1.1in and can be separated from the EV kit using the cutout slots, allowing the
MAX5422 to be conveniently attached to a user application. After separation, the two parts of the EV kit can
be reconnected using a short cable. A short ribbon
cable of about 3in is recommended to reconnect the
MAX5422 EV kit. A Samtec IDSS-06-D-3.00 ribbon
cable can be used to connect header J1 odd pins to
header J2 odd pins.
Jumper Selection
Using an External DC Power Supply
The MAX5422 EV kit can be powered by an external
2.7V to 5.25V DC power supply. The EV kit can still be
programmed through the USB interface using the software GUI. To connect the EV kit to an external power
supply, disconnect the USB cable and install a shunt
on pins 2-3 of jumper JU1. Turn off the power supply
and connect the power-supply ground terminal to the
EV kit GND pad, and the power-supply positive terminal
to the VCC pad. Table 2 lists the various options for
powering the MAX5422 EV kit.
Table 2. JU1 Jumper Functions (VDD)
SHUNT
POSITION
VDD PIN CONNECTED
TO
EV KIT POWERED
FROM
1-2*
3.3V
USB interface circuit
2-3
VCC
External power supply
(2.7V to 5.25V)
Open
Not connected
Do not use (EV kit is
not powered)
*Default position.
SPI Clock and Data/Chip Select Inputs
The MAX5422 features a clock and data/chip select input
pins for SPI-compatible communication to control the
MAX5422 wiper position and transfer data between volatile
and nonvolatile memories. The clock and data/chip select
pins can be driven by the on-board USB interface circuit
or the PCB header (J2), along with a user-supplied external SPI-compatible controller. An external SPI-compatible
controller can be connected to the SCLK (J2-6), DIN (J28), CS (J2-10), and GND (J2-12) on header J2 to communicate with the MAX5422 IC. When using an external SPIcompatible controller, disconnect the on-board USB interface circuit by removing all the shunts from header J1.
Headers J1 and J2 select the SPI serial-interface signalcontrol sources for the MAX5422 IC. Table 3 lists the
various options for configuring SPI input signal controls.
Table 3. J1, J2 Header Functions (+3.3V, VDD, SCLK, DIN, CS, GND)
HEADER POSITION
J1 (1-2)
J1 (3-4)
J1 (5-6)
J1 (7-8)
J1 (9-10)
J1 (11-12)
SHUNT POSITION
Installed*
Not installed
Installed*
Not installed
Installed*
Not installed
Installed*
Not installed
Installed*
EV KIT FUNCTION
Connects +3.3V from USB interface to MAX5422
Disconnect +3.3V from USB interface to MAX5422
Connects VDD from MAX5422 to USB interface
Disconnect VDD from MAX5422 to USB interface
Connects SCLK from USB interface to MAX5422
Disconnect SCLK from USB interface to MAX5422
Connects DIN from USB interface to MAX5422
Disconnect DIN from USB interface to MAX5422
Connects CS from USB interface to MAX5422
Not installed
Disconnect CS from USB interface to MAX5422
Not installed
Shunt not required
Not installed
Do not install shunts on these pins. Shunts will short the power and signal
lines to ground.
Not installed
Shunt not required
J2 (1-2)
J2 (3-4)
J2 (5-6)
J2 (7-8)
J2 (9-10)
J2 (11-12)
*Default position.
8
_______________________________________________________________________________________
MAX5422 Evaluation Kit
Note that to test the device in resistor mode, the ohmmeter must be ground referenced to the MAX5422 by connecting the L pin to GND or the H pin to VDD.
Resistance can then be measured between W and L or
W and H.
Evaluating the MAX5423ETA/MAX5424ETA
The MAX5422 EV kit can also evaluate the
MAX5423ETA or the MAX5424ETA. Remove the
MAX5422ETA IC (U1) and replace it with the desired IC.
The MAX5423ETA and MAX5424ETA ICs are pin and
functional compatible with the MAX5422ETA IC. Refer to
the MAX5422/MAX5423/MAX5424 IC data sheet
for a complete description of part-to-part differences.
Table 4. JU2 and JU3 Jumper Functions (L Signal and GND)
SHUNT POSITION
JU2
Not installed*
1-2
2-3**
JU3
Not installed*
Installed
Not installed
Installed
Not installed
Installed
H PAD
Not connected
Connected to VDD
Connected to W pad
L PAD
Not connected
Connected to GND
Not connected
Connected to GND
Not connected
Connected to GND
MAX5422 FUNCTION
Potentiometer open ends
Potentiometer with ground reference
Voltage-divider open end
Voltage-divider with ground reference
Variable resistor open ends
Variable resistor with ground reference
*Default position.
**Any power source connect to the H or W pad must be current limited.
_______________________________________________________________________________________
9
Evaluates: MAX5422/MAX5423/MAX5424
Potentiometer, Voltage-Divider, or
Variable Resistor, with Ground Reference
The MAX5422 EV kit provides an option to configure the
MAX5422 as a potentiometer, voltage-divider, or variable resistor—open end(s), or with ground reference
using jumpers JU2 and JU3. Table 4 lists the various
JU2 and JU3 jumper options.
Warning: When operating as a variable resistor (jumper
JU2 shunts on pins 2-3), any power source connected
to the H, W, or L pad must be voltage and current limited to the absolute maximum conditions stated in the
MAX5422/MAX5423/MAX5424 IC data sheet.
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
Figure 4a. MAX5422 EV Kit Schematic (Sheet 1 of 2)
10
______________________________________________________________________________________
MAX5422 Evaluation Kit
Evaluates: MAX5422/MAX5423/MAX5424
Figure 4b. MAX5422 EV Kit Schematic (Sheet 2 of 2)
______________________________________________________________________________________
11
Evaluates: MAX5422/MAX5423/MAX5424
MAX5422 Evaluation Kit
Figure 5. MAX5422 EV Kit Component Placement Guide—
Component Side
12
Figure 6. MAX5422 EV Kit PCB Layout—Component Side
______________________________________________________________________________________
MAX5422 Evaluation Kit
Figure 8. MAX5422 EV Kit Component Placement Guide—
Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
Evaluates: MAX5422/MAX5423/MAX5424
Figure 7. MAX5422 EV Kit PCB Layout—Solder Side