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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.
MAX9634 Evaluation Kit
Evaluates: MAX9634
General Description
The MAX9634 evaluation kit (EV kit) provides a proven
design to evaluate the MAX9634 high-side current-sense
amplifier, which offers precision accuracy specifications
of VOS less than 250µV (max) and gain error less than
0.5% (max). This EV kit demonstrates the MAX9634 in
a tiny 1mm x 1mm x 0.6mm, 4-bump UCSP™ package.
The MAX9634 is also available in a 5-pin SOT23, but that
package is not compatible with this EV kit.
The EV kit PCB comes with a MAX9634FERS+ installed,
which is the 50V/V gain version. Contact the factory for
free samples of the pin-compatible MAX9634TERS+,
MAX9634HERS+, and MAX9634WERS+, which are
25V/V, 100V/V, and 200V/V gain versions, respectively.
Features
S Precision Real-Time Current Monitoring
S 1.6V to 28V Input Common-Mode Range
S Proven PCB Layout
S Fully Assembled and Tested
19-5174; Rev 0; 3/10
UCSP is a trademark of Maxim Integrated Products, Inc.
Component List
Ordering Information
+Denotes lead(Pb)-free and RoHS compliant.
Component Suppliers
Note: Indicate that you are using the MAX9634 when contacting these component suppliers.
PART TYPE
MAX9634EVKIT+ EV Kit
DESIGNATION QTY DESCRIPTION
C1 1
1FF Q10%, 50V X7R ceramic
capacitor (1206)
Murata GRM31MR71H105KA
C2 0 Not installed, ceramic capacitor
(0603)
R1 1
0.05I Q0.5%, 0.5W 4-terminal
current-sense resistor (1206)
Ohmite LVK12R050DER
TP1, TP2 2 Test points
U1 1
Precision current-sense amplifier
(4 UCSP)
Maxim MAX9634FERS+
(Gain: 50V/V)
(Top Mark: +ABY)
— 1 PCB: MAX9634 EVALUATION
KIT+
SUPPLIER PHONE WEBSITE
Murata Electronics North America Inc. 770-436-1300 www.murata-northamerica.com
Ohmite Mfg. Co. 866-964-6483 www.ohmite.com
MAX9634 Evaluation Kit
Evaluates: MAX9634
2 ______________________________________________________________________________________
Quick Start
Recommended Equipment
• MAX9634 EV kit
• 3.6V, 1A DC power supply
• An electronic load capable of sinking 800mA
(e.g., HP 6060B)
• Two digital voltmeters
Procedure
The MAX9634 EV kit is fully assembled and tested. Follow
the steps below to verify board operation. Caution: Do
not turn on the power supply or electronic load until
all connections are completed.
1) Connect the positive terminal of the 3.6V supply to
the VBATT pad and the negative terminal of the sup-
ply to the GND pad closest to the VBATT pad.
2) Set the electronic load to sink 800mA.
3) Connect the electronic load’s positive terminal to the
LOAD pad and the negative terminal to the GND pad
closest to the bottom of the EV kit.
4) Connect the first voltmeter across test points TP1 and
TP2 to measure VSENSE.
5) Connect the second voltmeter across the VOUT pad
and the closest GND pad.
6) Turn on the power supply.
7) Turn on the electronic load.
8) Verify that the first voltmeter reading is approximately
40mV and the second voltmeter is approximately 2V.
9) Adjust the current load from 800mA to 0A and verify
that the reading of the second voltmeter is approxi-
mately 50 times the reading of the first voltmeter.
Note: If the voltmeter has a 10Mω input resistance, the
output voltage reads 0.1% low.
Detailed Description of Hardware
The MAX9634 EV kit provides a proven design to evalu-
ate the MAX9634 high-side current-sense amplifier,
which offers precision accuracy specifications of VOS
less than 250µV (max) and gain error less than 0.5%
(max).
Applying the VRS+ Supply and the Load
The EV kit is installed with a MAX9634FERS+, which has
a gain of 50V/ V. The current-sense resistor (RSENSE)
value is 0.05I with Q0.5% tolerance. The voltage at the
VOUT pad is given by:
OUT LOAD SENSE OS V
V (I R V ) A= × + ×
where VOS is the offset, AV is the gain, and ILOAD is the
current load applied to the device. Normal operating
VRS+ and VRS- range is 1.6V to 28V.
Measuring the Load Current
The load current is measured as a voltage drop (VSENSE)
across an external sense resistor. This voltage is then
amplified by the current-sense amplifier and presented
at the VOUT pad. Like all differential amplifiers, the
output voltage has two components of error (an offset
error and a gain error). The offset error affects accuracy
at low currents and the gain error affects accuracy at
large currents—both errors affect accuracy at intermedi-
ate currents. By minimizing both offset and gain errors,
accuracy is optimized over a wide dynamic range.
Evaluating Other Gain Versions
The MAX9634 EV kit can also be used to evaluate other
gain versions of the MAX9634 (25V/V, 100V/V, or 200V/V
with a T, H, or W suffix, respectively). Replace U1 on the EV
kit with a different version of the MAX9634 IC.
MAX9634 Evaluation Kit
Evaluates: MAX9634
_______________________________________________________________________________________ 3
Figure 1. MAX9634 EV Kit Schematic
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.
4 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX9634 Evaluation Kit
Evaluates: MAX9634
Figure 4. MAX9634 EV Kit PCB Layout—Solder Side
Figure 2. MAX9634 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX9634 EV Kit PCB Layout—Component Side
1.0”
1.0”
1.0”
