General Description
The MAX9939 evaluation kit (EV kit) is a fully assembled
and tested surface-mount PCB that evaluates the
MAX9939 SPI™-programmable gain amplifier (PGA). Its
internal op amp is configured as a multiple-feedback
active filter by default, but can also be reconfigured so
the MAX9939 operates as a differential-input, differen-
tial-output programmable gain amplifier. The EV kit fea-
tures an on-board microcontroller, which receives
commands from a PC through the USB port. The EV kit
can be powered directly from the USB bus or from a
single-supply voltage of 2.9V to 5.5V.
The EV kit also includes Windows®2000/XP- and
Windows Vista®-compatible software that provides a
simple user interface for exercising the MAX9939 fea-
tures. The program is menu driven and offers a graphical
user interface (GUI) complete with control buttons and
status displays. The GUI demonstrates the programma-
ble gains from 0.2V/V to 157V/V and the input offset volt-
age compensation features of the MAX9939 IC.
Features
oPowered Directly from a USB Port
oOn-Board Microcontroller to Generate SPI
Commands
oEasy-to-Use, Menu-Driven Software
oSurface-Mount Components
oLead(Pb)-Free and RoHS Compliant
oFully Assembled and Tested
Evaluates: MAX9939
MAX9939 Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
19-4407; Rev 0; 1/09
Component List
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.
Ordering Information
DESIGNATION QTY DESCRIPTION
C1, C2, C4–C8,
C12, C17, C19 10
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K
TDK C1608X7R1C104K
C3 1
4.7µF ±10%, 6.3V X5R ceramic
capacitor (0603)
Murata GRM188R60J475K
TDK C1608X5R0J475K
C13, C15 2
10µF ±20%, 16V X5R ceramic
capacitors (1206)
Murata GRM31CR61C106M or
TDK C3216X5R1C106M
C9 1
0.033µF ±10%, 25V X7R ceramic
capacitor (0603)
Murata GRM188R71E333K
TDK C1608X7R1E333K
C10, C11 2
22pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H220J
TDK C1608C0G1H220J
DESIGNATION QTY DESCRIPTION
C14 1
1µF ±10%, 16V X5R ceramic
capacitor (0603)
Murata GRM188R61C105K
TDK C1608X5R1C105K
C16, C18 2
10pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H100J
TDK C1608C0G1H100J
C20 1
4700pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H472K
TDK C1608X7R1H472K
C21 1
220pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H221K
TDK C1608X7R1H221K
C22 0 Not installed, capacitor (0603)
D1 1 Green LED (0805)
FB1 1
70Ω, 4A ferrite bead (0603)
TDK MMZ1608R301A
Murata BLM18SG700 TN1
PART TYPE
MAX9939EVKIT+ EV Kit
SPI is a trademark of Motorola, Inc.
Windows and Windows Vista are registered trademarks of Microsoft Corp.
+
Denotes lead(Pb)-free and RoHS compliant
Evaluates: MAX9939
MAX9939 Evaluation Kit
2 _______________________________________________________________________________________
Component List (continued)
DESIGNATION QTY DESCRIPTION
H1 0 Not installed, 2 x 5-pin JTAG header
H2 0 Not installed, 2 x 6-pin JTAG header
IN_DIFF,
OUT_DIFF 275Ω BNC PCB-mount connectors
JU1 1 3-pin header
P1 1 USB type-B right-angle PC-mount
receptacle
R1, R2 2 27Ω ±5% resistors (0603)
R3 1 1.5kΩ ±5% resistor (0603)
R4, R7 2 470Ω ±5% resistors (0603)
R5 1 2.2kΩ ±5% resistor (0603)
R6 1 10kΩ ±5% resistor (0603)
R8, R17, R24,
R25 40Ω resistors (0603)
R9, R10, R11,
R22, R23 0 Not installed, resistors (0603)
R12–R16 0 Not installed, resistors—short PC
trace (0603)
R18, R19 2 66.5kΩ ±1% resistors (0603)
R20 1 121kΩ ±1% resistor (0603)
R21 1 1.21kΩ ±1% resistor (0603)
DESIGNATION QTY DESCRIPTION
U1 1
SPI programmable gain amplifier
(10 µMAX®)
Maxim MAX9939AUB+
U2 1
Low-voltage level translator
(14 TSSOP)
Maxim MAX3390EEUD+
U3 1
Low-power 16-bit microcontroller
(68 QFN-EP*)
Maxim MAXQ2000-RAX+
U4 1 LDO regulator (5 SO70)
Maxim MAX8511EXK25+
U5 1 UART-to-USB converter (32 TQFP)
FTDI FT232BL
U6 1 93C46 3-wire 16-bit EEPROM (8 SO)
Atmel AT93C46A-10SU-2.7
Y1 1 16MHz crystal
Y3 1 6MHz crystal
— 1 Shunt
— 1 PCB: MAX9939 Evaluation Kit+
*
EP = Exposed pad.
Note: Indicate that you are using the MAX9939 when contacting these component suppliers.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Component Suppliers
SUPPLIER PHONE WEBSITE
Murata Manufacturing Co., Ltd. 770-436-1300 www.murata.com
TDK Corp. 847-803-6100 www.component.tdk.com
MAX9939 EV Kit Files
PART DESCRIPTION
INSTALL.EXE Installs the EV kit files on your computer
MAX9939.EXE Application program
FTD2XX.INF USB device driver file
UNINST.INI Uninstalls the EV kit software
USB_Driver_Help.PDF USB driver installation help file
Evaluates: MAX9939
MAX9939 Evaluation Kit
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Quick Start
Recommended Equipment
Before beginning, the following equipment is needed:
• A user-supplied Windows 2000/XP/Vista-compatible
PC with a spare USB port
• Signal generator
• Oscilloscope
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.
Procedure
The MAX9939 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on power supplies until all
connections are completed.
1) Visit www.maxim-ic.com/evkitsoftware to down-
load the latest version of the EV kit software,
9939Rxx.ZIP. Save the EV kit software to a tempo-
rary folder and uncompress the ZIP file.
2) Install the EV kit software on your computer by run-
ning the INSTALL.EXE program inside the tempo-
rary folder. The program files are copied and icons
are created in the Windows Start | Programs
menu.
3) Verify that a shunt is installed across pins 2-3 of
jumper JU1 (USB powered).
4) Connect the USB cable from the PC to the EV kit
board. A New Hardware Found window pops up
when installing the USB driver for the first time. If a
window that is similar to the one described above is
not seen after 30s, remove the USB cable from the
board and reconnect it. Administrator privileges are
required to install the USB device driver on
Windows.
5) 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\MAX9939 (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 for additional
information.
6) Start the EV kit software by opening its icon in the
Start | Programs menu. The EV kit software main
window appears, as shown in Figure 1. Observe as
the program automatically detects the MAX9939 EV
kit and starts the main program.
7) Set the signal generator to produce an output sig-
nal of 25mV peak-to-peak at a frequency of 1kHz.
8) Connect the signal generator to the IN_DIFF BNC
connector.
9) Connect the oscilloscope to the OUT_DIFF BNC
connector.
10) Enable the signal generator.
11) Adjust the gain and offset settings using the provided
software. See the
Detailed Description of Software
section to evaluate the features of the EV kit.
12) Monitor and verify the output with the oscilloscope.
Detailed Description of Software
The MAX9939 EV kit software GUI (Figure 1) is a
Windows program that provides a convenient means to
control the MAX9939. By updating the Gain/Offset
Setting group box or Shutdown checkbox, the correct
SPI-compatible write operation is generated to update
the internal registers of the MAX9939. Note, updating
only the select radio group does not modify the internal
registers.
Select
The Select radio group of the MAX9939 EV kit GUI con-
trols the SEL bit to select which internal register is writ-
ten to. Select Gain to write to the gain register or select
Offset to write to the input offset voltage trim register.
Figure 1. MAX9939 EV Kit Software Main Window
Evaluates: MAX9939
Programming Gain and Input
Offset Voltage
The Gain/Offset Setting group box of the MAX9939 EV
kit software controls the data written to the two internal
registers of the MAX9939 IC. The Gain Selection drop-
down list writes to the gain register to set the gain of the
amplifier. The Input Offset(mV) drop-down list writes to
the input offset voltage (VOS) register to cancel the
inherent offset voltage of the amplifier. Refer to Tables
3 and 4 in the MAX9939 IC data sheet for gain and
input offset voltage settings.
Shutdown
The Shutdown checkbox of the MAX9939 EV kit GUI
allows the user to place the device in a low-power shut-
down mode with only the digital part of the chip staying
active. Leave the Shutdown checkbox unchecked for
normal circuit operation.
General-Purpose 3-Wire (SPI)
Interface Utility
The general-purpose 3-wire interface utility (Figure 2)
can also be used to communicate with the MAX9939
using low-level SPI commands. Select the Options |
Interface menu item and select the 3-wire interface
tab to access the utility. The utility configures the 3-wire
serial-interface parameters, such as MSB position,
CPOL, CPHA, MOSI/MISO inverted logic, CS active
state (high or low), SPI clock (SCLK) speed, and cus-
tom selection of SPI signal pins. The data to be sent is
MAX9939 Evaluation Kit
4 _______________________________________________________________________________________
Figure 2. MAX9939 Interface Diagnostic Window
8-bit data represented by a two-digit hexadecimal
code. The code is entered in the Data bytes to be writ-
ten edit box and transmitted by pressing the Send
Now button.
Detailed Description of Hardware
Power Input
The MAX9939 EV kit operates from a single supply
VCC between 2.9V to 5.5V. Using 3-pin jumper JU1,
the EV kit can be powered through the host PC’s USB
port or by an external power supply. By default, a shunt
is installed across pins 2-3 and the USB provides 5V
(+5VUSB) to power the EV kit. Install a shunt across
pins 1-2 to use an external power supply applied at the
VCC pad. Table 1 lists the selectable jumper options.
Default Configuration as an Active Filter
The MAX9939 EV kit comes standard with the
MAX9939 configured as an anti-aliasing filter to provide
a cutoff frequency to maximize the Nyquist bandwidth
of an ADC. The external resistors and capacitors are
chosen to create a 1.3kHz lowpass, 3rd-order, 0.1dB
Chebyshev multiple-feedback active filter. Refer to the
Applications Information
section in the MAX9939 IC
data sheet for a more detailed description of using the
MAX9939 IC as an active filter.
Evaluating the EV Kit as a Differential-
Input, Differential-Output PGA
The MAX9939 EV kit can also be evaluated as a differ-
ential-input, differential-output programmable gain
amplifier by configuring the output stage as follows:
1) Remove R24, R25, C20, and C21.
2) Replace R20 with a 0Ωresistor.
3) Replace R18 and R19 with 10kΩresistors.
4) If an anti-aliasing filter is required, replace C2, C22
and R21, R22 capacitor/resistor values as required.
If an anti-aliasing filter is not required, replace R21
and R22 with 0Ωresistors while leaving C2 and C22
open.
5) Utilize the OUT_DIFF BNC connector to analyze the
differential output. Caution: Ensure that pin 2 of
the IN_DIFF BNC connector and pin 2 of the
OUT_DIFF BNC connector are isolated from each
other (i.e., not shorted together).
Evaluates: MAX9939
MAX9939 Evaluation Kit
_______________________________________________________________________________________ 5
SHUNT
POSITION VCC DESCRIPTION
1-2 EV kit requires an external power supply
applied at the VCC pad
2-3* EV kit is powered through the host PC’s
USB port (+5VUSB)
Table 1. Jumper JU1 Functions (VCC)
*
Default position.
Evaluates: MAX9939
MAX9939 Evaluation Kit
6 _______________________________________________________________________________________
Figure 3a. MAX9939 EV Kit Schematic (Sheet 1 of 3)
Evaluates: MAX9939
MAX9939 Evaluation Kit
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Figure 3b. MAX9939 EV Kit Schematic (Sheet 2 of 3)
Evaluates: MAX9939
MAX9939 Evaluation Kit
8 _______________________________________________________________________________________
Figure 3c. MAX9939 EV Kit Schematic (Sheet 3 of 3)
Evaluates: MAX9939
MAX9939 Evaluation Kit
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Figure 4. MAX9939 EV Kit Component Placement Guide—Component Side
Evaluates: MAX9939
MAX9939 Evaluation Kit
10 ______________________________________________________________________________________
Figure 5. MAX9939 EV Kit Component PCB Layout—Component 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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
11
© 2009 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Evaluates: MAX9939
MAX9939 Evaluation Kit
Figure 6. MAX9939 EV Kit PCB Layout—Solder Side
