MAX1968EVKIT ,Evaluation Kit for the MAX1968FeaturesThe MAX1968 evaluation kit (EV kit) is a fully assembled ±3A Output Currentand tested PC b ..
MAX196ACAI ,Multirange, Single %V, 12-Bit DAS with 12-Bit Bus InterfaceApplicationsMAX196D8 6 23 REFMAX198Industrial-Control SystemsD7 7 22 REFADJRoboticsD6 8 21 CH5Data- ..
MAX196ACAI+ ,6-Channel, Multirange, 5V, 12-Bit DAS with 12-Bit Bus Interface and Fault ProtectionFeatures♦ 12-Bit Resolution, 1/2LSB LinearityThe MAX196/MAX198 multirange, 12-bit data-acquisi-tion ..
MAX196ACAI+ ,6-Channel, Multirange, 5V, 12-Bit DAS with 12-Bit Bus Interface and Fault ProtectionFeatures♦ 12-Bit Resolution, 1/2LSB LinearityThe MAX196/MAX198 multirange, 12-bit data-acquisi-tion ..
MAX196ACNI+ ,6-Channel, Multirange, 5V, 12-Bit DAS with 12-Bit Bus Interface and Fault ProtectionFeatures♦ 12-Bit Resolution, 1/2LSB LinearityThe MAX196/MAX198 multirange, 12-bit data-acquisi-tion ..
MAX196ACNI+ ,6-Channel, Multirange, 5V, 12-Bit DAS with 12-Bit Bus Interface and Fault ProtectionApplicationsMAX196D8 6 23 REFMAX198Industrial-Control SystemsD7 7 22 REFADJRoboticsD6 8 21 CH5Data- ..
MAX4927ETN+ ,1000 Base-T, ±15kV ESD Protection LAN SwitchApplicationsSTMUX1000LNotebooks and Docking Stations ♦ Space-Saving Lead-Free PackageServers and Ro ..
MAX4928BETN+ ,DisplayPort/PCIe Passive SwitchesELECTRICAL CHARACTERISTICS(V = +3.3V ±10%, T =T to T , unless otherwise noted. Typical values are a ..
MAX4928BETN+T ,DisplayPort/PCIe Passive SwitchesApplicationsMAX4928BETN+ -40°C to +85°F 56 TQFN-EPDesktop PCs+Denotes a lead-free package/RoHS-Comp ..
MAX492CPA ,Single/Dual/Quad, Micropower, Single-Supply Rail-to-Rail Op AmpsELECTRICAL CHARACTERISTICS(V = 2.7V to 6V, V = GND, T = +25°C, unless otherwise noted.)CC EE APARAM ..
MAX492CPA ,Single/Dual/Quad, Micropower, Single-Supply Rail-to-Rail Op AmpsFeatures' Low-Voltage Single-Supply Operation (+2.7V to +6V)The dual MAX492, quad MAX494, and singl ..
MAX492CPA+ ,Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op Amps Not Recommended for New Designs The MAX495 was manufactured for Maxim by an outside wafer foundr ..
MAX1968EVKIT
Evaluation Kit for the MAX1968
General DescriptionThe MAX1968 evaluation kit (EV kit) is a fully assembled
and tested PC board that implements a switch-mode
driver for a Peltier thermoelectric cooler (TEC) module.
It operates from a single 3.0V to 5.5V supply and pro-
vides a bipolar ±3A (max) output to the module.
A potentiometer, DAC, or external source generates a
DC temperature set-point voltage. Thermal feedback
from the TEC module is compared to the set-point volt-
age to generate the TEC current-control signal. The
MAX1968 accurately regulates the TEC current based
on this signal.
When using the DAC, the EV kit connects to the parallel
port of a computer running Windows® 95, 98, or 2000.
Software, included with the EV kit, provides a quick and
easy method to control the DAC.
Note:Windows 2000 requires the installation of a dri-
ver. Refer to Win2000.pdf or Win2000.txt located on the
diskette.
Features±3A Output CurrentOperates from a Single Supply (3.0V to 5.5V)High-Efficiency Switch-Mode Design500kHz or 1MHz Switching Frequency Programmable Heating/Cooling LimitTEC Current-Monitor OutputSPI™-Compatible Serial InterfaceEasy-to-Use Menu-Driven SoftwareIncludes Windows 95/98/2000-Compatible
Software and Demo PC BoardSurface-Mount ConstructionFully Assembled and Tested
Evaluates: MAX1968
MAX1968 Evaluation Kit19-2502; Rev 0; 6/02
Ordering Information*EP = Exposed pad.
Windows is a registered trademark of Microsoft Corp.
SPI is a trademark of Motorola, Inc.
Evaluates: MAX1968
MAX1968 Evaluation Kit
Component Suppliers
Evaluates: MAX1968
MAX1968 Evaluation Kit
Quick Start
Required EquipmentBefore beginning, the following equipment is required:A DC power supply capable of supplying any volt-
age between 3V and 5.5V at 3AA Peltier TEC module with a thermistor (10kΩat
+25°C)A digital voltmeter (DVM)
ProcedureThe MAX1968 EV kit is a fully assembled and tested
surface-mount board. Follow the steps below to verify
board operation.
Do not turn on the power supply
until all connections are completed:Place a shunt across pins 2 and 3 on JU1 to set the
frequency to 500kHz.Place a shunt across pins 2 and 3 on JU4 to select
the potentiometer.Place a shunt across pins 2 and 3 on JU2 to dis-
able the MAX1968 output.Obtain TEC module specifications for absolute
maximum TEC voltage, absolute maximum cooling
current, and absolute maximum heating current. Set
these (or lower) limits at the MAX1968 MAXV,
MAXIP (heating current), and MAXIN (cooling cur-
rent) inputs. See Tables 1, 2, and 3to select resis-
tors or refer to the MAX1968 data sheet.Connect the TEC module to OS1, OS2, THERM,
and GND. Typical connections for most modules
are:Module TEC- to OS1Module TEC+ to OS2Module thermistor to THERMSecond module thermistor pin to GNDModule case ground or shield to GND
Be sure to check module specifications before
making connections. Also, it is recommended that
the thermistor be connected through shielded wire
for lowest noise.Connect the DVM to SET-POINT-IN and GND.Connect a 3.3VDC or 5VDC power supply with suffi-
cient power rating to VDD and GND.Turn on the power supply.Adjust R22 until the DVM reads 0.75V. This adjusts
the set point for approximately +25°C.
10)Move the DVM positive lead to THERM and verify a
voltage of approximately 0.75V. This represents
+25°C at the TEC module.
11)Enable the MAX1968 by moving the shunt on JU2
to the 1 and 2 position.
12)After enabling the MAX1968, verify that the THERM
voltage converges toward the set-point voltage on
R22 (set to 0.75V in step 9) after approximately
30s. If the TEC is connected backwards, the THERM
voltage moves away from 0.75V toward either 0V or
1.5V. If this occurs, shut down the MAX1968 and
reverse the TEC+ and TEC- connections
13)Once operation is verified, other temperatures may
be set with R22, the DAC, or an external voltage
applied to SET-POINT-IN; 1V is approximately
+10°C and 0.5V is approximately +40°C. The slope
is approximately -14mV/°C.
Detailed Description
Voltage and Current-Limit SettingsThe MAX1968 provides control of the maximum differ-
ential TEC voltage and the maximum positive and neg-
ative TEC current. The voltage on the MAXV pin of the
MAX1968 sets the maximum differential TEC voltage.
Use the following equations to set the voltage:
Voltage on MAXV:
Maximum TEC Voltage:
The components installed on the MAX1968 EV kit set
Evaluates: MAX1968
MAX1968 Evaluation KitVMAXVto 1V, for a maximum TEC voltage of 4V. See
Table 1and refer to the MAX1968 data sheet for more
information. The voltages on the MAXIP and MAXIN
pins set the maximum positive (heating) and negative
(cooling) current through the TEC. Use the following
equations to set the currents:
Voltage on MAXIP:
Voltage on MAXIN:
Resistor values for R2 through R7 should be between
10kΩand 100kΩ:
Maximum Positive TEC Current:
where RSENSE(R1) is 50mΩ:
Maximum Negative TEC Current:
The components installed on the MAX1968 EV kit limit
the maximum positive current to +3A and the maximum
negative current to -1.5A. See Tables 2 and 3, and refer
to the MAX1968 data sheet for more information.
Jumper JU1Jumper JU1 sets the switching frequency for the
MAX1968. Positions 1 and 2 set the frequency to 1MHz.
Positions 2 and 3 set the frequency to 500kHz.
Jumper JU2The MAX1968 can be placed in shutdown mode using
jumper JU2. See Table 4for jumper settings.
Jumper JU3Jumper JU3 connects the current-control input (CTLI)
of the MAX1968 to the thermal loop circuit. The thermal
loop circuit compares thermistor feedback from the
TEC module to the set-point voltage to generate the
CTLI signal.
To drive CTLI directly, cut the trace shorting JU3 and
apply a DC voltage between 0 and 3V to the CTLI pad;
1.5V on CTLI sets a TEC current of approximately 0A. A
voltage of 0V or 3V on CTLI produces -3A or +3A,
respectively. The current changes proportionally with
the voltage applied to CTLI.
Note:The current does not reach ±3A if the maximum
positive and negative current limits are set to lower val-
ues. See the Voltage and Current-Limit Settingssection
and refer to the MAX1968 data sheet for more information.
Jumper JU4Jumper JU4, in positions 1 and 2, connects the DAC to
the thermal loop circuit. Connect the EV kit to the paral-
lel port of a computer and use the EV kit software to
control the DAC. Positions 2 and 3 connect potentiome-
ter R22 to the thermal loop circuit.
To use an external voltage to control the thermal loop,
remove the shunt from JU4 and apply the voltage to the
SET-POINT-IN pad. A voltage of 0.75V corresponds to
approximately +25°C; 1V is approximately +10°C and
0.5V is approximately +40°C. The slope is approxi-
mately -14mV/°C.
Switch SW1Switch SW1 resets the DAC to 0.75V.
ITEC Current-Monitor OutputThe ITEC output provides a voltage proportional to the
actual TEC current. VITEC= REF when TEC current is
zero. The actual TEC current is:
Use ITEC to monitor the cooling or heating current
through the TEC module. Positive values of ITEC indi-
cate heating for typically connected modules. The max-
imum capacitance that ITEC can drive is 100pF.
*Default position
Using a Computer
Required EquipmentIn addition to the equipment listed under the Quick
Startsection, the following equipment is necessary:A computer running Windows 95, 98, or 2000.
Note:Windows 2000 requires the installation of a
driver; refer to Win2000.pdf or Win2000.txt located
on the diskette.A parallel printer port (this is a 25-pin socket on the
back of the computer).A standard 25-pin, straight-through, male-to-female
cable (printer extension cable) to connect the com-
puter’s parallel port to the MAX1968 EV kit.
ProcedurePlace a shunt across pins 2 and 3 on JU1 to set the
frequency to 500kHz.Place a shunt across pins 1 and 2 on JU4 to select
the DAC.Place a shunt across pins 2 and 3 on JU2 to dis-
able the MAX1968 output.Obtain TEC module specifications for absolute
maximum TEC voltage, absolute maximum cooling
current, and absolute maximum heating current. Set
these (or lower) limits at the MAX1968 MAXV,
MAXIP (heating current), MAXIN (cooling current)
inputs. See Tables 1, 2, and 3to select resistors or
refer to the MAX1968 data sheet.Connect the TEC module to OS1, OS2, THERM,
and GND. Typical connections for most modules
are:Module TEC- to OS1Module TEC+ to OS2Module thermistor to THERMSecond module thermistor pin to GNDModule case ground or shield to GND
Be sure to check module specifications before
making connections. Also, it is recommended that
the thermistor be connected through shielded wire
for lowest noise.Connect a cable from the computer’s parallel port
to the MAX1968 EV kit. Use a straight-through 25-
pin female-to-male cable. To avoid damaging the
EV kit or your computer, do not use a 25-pin SCSI
port or any other connector that is physically similar
to the 25-pin parallel printer port.The MAX1968.EXE software program can be run
from the floppy or hard drive. Use the Windows pro-
gram manager to run the program. If desired, the
INSTALL.EXE program may be used to copy the
files and create icons for them in the Windows
95/98/2000 start menu. An uninstall program is
included with the software. Click on the UNINSTALL
icon to remove the EV kit software from the hard
drive.Connect a 3.3VDC or 5VDC power supply with suffi-
cient power rating to VDD and GND.Turn on the power supply.
10)Start the MAX1968 program by opening its icon in
the start menu. At program startup, the software
forces the DAC to 0.75V, which corresponds to
approximately +25°C.
11)Connect the DVM to THERM and verify a voltage of
approximately 0.75V. This represents +25°C at the
TEC module.
12)Enable the MAX1968 by moving the shunt on JU2
to the 1 and 2 position.
13)After enabling the MAX1968, verify that the THERM
voltage converges toward the DAC voltage (0.75V)
after approximately 30s. If the TEC is connected
backwards, the THERM voltage moves away from
0.75V toward either 0V or 1.5V. If this occurs, shut
down the MAX1968 and reverse the TEC+ and
TEC- connections.
14)Once operation is verified, other temperatures may
be set with the DAC. See the User Interfacesection.
User InterfaceThe user interface is easy to operate. Use either the
mouse or the Tab key to navigate. To program the
DAC, enter the ratio of the desired DAC output voltage
(VDAC) to the reference voltage (REF). See the equation
below:
where REF = 1.5V. The ratio must be a decimal number
between 0 and 1. Press Enter or click on the Update
button to send the data to the DAC. A ratio of 0.67 sets
the DAC output to 1V, which corresponds to approxi-
mately +10°C. A ratio of 0.33 sets the DAC output to
0.5V, or approximately +40°C. The slope is approxi-
mately -14mV/°C.
Evaluates: MAX1968
MAX1968 Evaluation Kit
Evaluates: MAX1968
General-Purpose SPI UtilityThere are two methods for communicating with the
MAX5144 DAC: through the user-interface panel or
through the general-purpose SPI utility. This utility
(Figure 3) configures SPI parameters such as clock
polarity (CPOL), clock phase (CPHA), and chip-select
(CS) polarity.
The fields where pin numbers are required apply to the
pins of the parallel port connector.
The utility handles the data only in byte (8-bit) format.
Data longer than a byte must be handled as multiple
bytes. For example, a 16-bit word should be broken
into two 8-bit bytes.
To write data to the slave device, enter the data into the
field labeled Data Bytes to be Written. Each data byte
should be hexadecimal, prefixed by 0x, and separated
with a comma. Press the Send Now button to write the
data to the slave.
To read data from the slave device, the field labeled
Data Bytes to be Written must contain hexadecimal val-
ues. Include the same number of bytes as to be read
from the slave.
Note:The MAX5144 is a write-only device and cannot
be read.
MAX1968 Evaluation Kit
