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19-1336; Rev 2; 11/98
MAX1703 Evaluation Kit
________________General Description
The MAX1703 evaluation kit (EV kit) provides a regulat-
ed 5.0V output while operating on input voltages as low
as 1.2V. The input may be a DC source or a 1 to 3-cell
battery. Efficiency is up to 95%, and output loads are
up to 1A.
The kit, which uses surface-mount components, is fully
assembled and tested for quick evaluation. Jumpers
are provided to select the output voltage, switching
mode, and shutdown control.
____________________________Features
o
5.0V Output
o
1A Output Current
o
1.2V to 5.5V Input
o
Up to 95% Efficiency
o
0.1µA Shutdown Current
o
300kHz PWM Operation
o
Optional Low-Power Mode
o
Small Surface-Mount Components
Evaluates: MAX1703
____________________ Component List
DESIGNATION QTY
C1, C2, C3
C4
3
1
DESCRIPTION
0.22µF, 25V ceramic capacitors
100µF, 10V low-ESR tantalum capacitor:
AVX TPSD107M010R0100 or
Sprague 593D107X0010D
220µF, 10V low-ESR tantalum capacitors
AVX TPSE227M010R0100 or
Sprague 593D227X0010E
Not installed, optional user capacitor
0.5A, 20V Schottky diode
Motorola MBR0520L
4.7µH, 3.2A power inductor
Sumida CDH74-4R7
Coilcraft DO3316-4R7,
Coiltronics UP2B-4R7 or
Sumida CDRH 104, 4746-JPS-007
3-pin jumpers
2-pin jumpers
100kΩ 1% resistors
Not installed, user-selected resistor
10Ω, 5% resistor
100kΩ, 5% resistors
1MΩ, 5% resistors
MAX1703ESE
Shunts
3.40” X 2.40” printed circuit board
MAX1703 data sheet
SUPPLIER
AVX
Coilcraft
Coiltronics
Motorola
Sprague
Sumida
J1, J2
J3, J4
R1, R7, R5
R2, R4, R6
R3
R8, R9
R10, R11
U1
None
None
None
2
2
3
0
1
2
2
1
4
1
1
PART
MAX1703EVKIT
Ordering Information
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
16 Narrow SO
C5, C6
C7
D1
2
1
1
Component Suppliers
PHONE
(803) 946-0690
(847) 639-6400
(561) 241-7876
(602) 244-5303
(603) 224-1961
(847) 956-0666
FAX
(803) 626-3123
(847) 639-1469
(561) 241-9339
(602) 244-4015
(603) 224-1430
(847) 956-0702
L1
1
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX1703 Evaluation Kit
Evaluates: MAX1703
_________________________Quick Start
The MAX1703 EV kit is shipped fully assembled and
tested. Follow these steps to verify board operation.
Do
not turn on the power supply until all connections
are completed.
1) Verify that the shunts are connected as listed in
Table 2 for a 5V output.
2) Connect a 1.2V to 5.5V supply to the VIN pad. The
ground connects to the GND pad.
3) Connect a voltmeter to the VOUT pad.
4) Turn on the power, and verify that the output volt-
age is 5V.
5) Connect a load if any.
power inductor must not saturate at the 3.2A peak cur-
rent produced by MAX1703. All inductors listed in the
component list have high current ratings and low coil
resistance.
The input and output capacitors must have low equiva-
lent-series resistance (ESR) to handle the high peak
currents found in switching regulators. Low ESR is
especially critical in low-voltage circuits to reduce the
AC voltage across the capacitors. A higher ESR on the
output capacitor will increase the output ripple.
Consider using parallel capacitors to reduce the total
ESR if the application requires lower output ripple.
A low-ESR input capacitor must be located physically
close to the inductor. A Schottky diode is used for the
lower forward voltage drop as well as the fast switching
characteristic. The diode selected for the evaluation
board was selected for its small size. The Schottky
diode must be connected between LX and POUT as
close to the IC as possible.
A separate low-noise ground plane connects pin 5 to
the reference and signal grounds. This low-noise
ground plane is then connected to the power ground
plane at the two PGND pins (Figure 4).
_______________Detailed Description
Jumper Selections
Four jumpers on the printed circuit board allow user
selection of several configurations. Table 1 lists the
jumpers and their functions. Table 2 lists the jumper
positions when the board is set for normal 5V output
operation.
______________Component Selection
The final circuit performance is determined by the qual-
ity of the components surrounding the MAX1703. The
Table 1. Jumper Functions
JUMPER
SHUNT
POSITION
1&2
J1
2&3
Open
1&2
J2
2&3
Open
Shorted
J3
Open
PIN CONNECTION
ON
connected to GND
ON
connected to VOUT
ON
is not controlled by
the board.
CLK/SEL pin connected
to GND
CLK/SEL pin connected
to VOUT
CLK/SEL connected to
CLK/SEL pad
FB pin connected to GND
FB pin connected to the
resistor divider
VOUT connected to
pull-up resistors
The pull-up resistors are
disconnected
MAX1703 OPERATION
The MAX1703 is enabled.
The MAX1703 is disabled.
ON
must be driven by a signal connected to the
ON
pad.
Low-power mode, the MAX1703 operates in the PFM mode.
High-power mode, the MAX1703 operates in the PWM mode.
CLK/SEL pin can be driven by an external source to select the power
mode or a 200kHz to 400kHz signal to control the switching frequency.
VOUT preset to 5V.
Output voltage determined by the R4-R5 resistor divider. Note: A
resistor must be installed in R4 to set the output voltage before
removing the shunt.
This jumper is necessary for normal circuit operation.
The J4 shunt should only be removed when testing the MAX1703
shutdown current.
Shorted
J4
Open
2
_______________________________________________________________________________________
MAX1703 Evaluation Kit
Evaluates: MAX1703
Table 2. Jumper Position for Normal 5.0V Operation
JUMPER
J1
J2
J3
J4
SHUNT
POSITION
1&2
2&3
Shorted
Shorted
PIN CONNECTION
ON
pin connected to GND.
CLK/SEL pin connected
to VOUT.
FB pin connected
to GND.
VOUT connected to the
pull-up resistors.
MAX1703 OPERATION
The MAX1703 is enabled.
High-power mode; the MAX1703 operates in the PWM mode.
VOUT is preset to 5V.
This shunt is necessary for normal circuit operation.
VIN 1.2V TO 5.3V
C4
100µF
10V
3
POKIN
R1
100k
1%
8
1
C1
0.22µF
VOUT
POK
REF
LXP
11
D1
MBR0520L
14
C5
220µF
10V
C6
220µF
10V
R2
OPEN
TO J4
L1
4.7µH
VOUT
POK
R9
100k
LXN
POUT
13
J4
U1
POUT
15
R3
10Ω
C3
0.22µF
C2
0.22µF
10V
J3
C7
OPEN
TO R9
MAX1703
OUT
4
R4
OPEN
R10
1M
3
ON
J1
2
1
16
ON
FB
2
R5
100k
1%
R8
100k
AO
AO
3
CLK/SEL
J2
2
1
GND
R11
1M
9
CLK/SEL
GND
5
PGND
10
AIN
PGND
12
7
6
R7
100k
1%
R6
OPEN
AIN
Figure 1. MAX1703 EV Kit Schematic
_______________________________________________________________________________________
3
MAX1703 Evaluation Kit
Evaluates: MAX1703
1.0"
1.0"
Figure 2. MAX1703 EV Kit Component Placement Guide
Figure 3. MAX1703 EV Kit PC Board Layout—Component Side
1.0"
Figure 4. MAX1703EV Kit PC Board Layout—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.
4
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.

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