19-1858; Rev 2; 7/05
MAX1709 Evaluation Kit
General Description
The MAX1709 evaluation kit (EV kit) is a step-up DC-DC
switching regulator for 1- to 3-cell battery inputs as well
as 2.5V or 3.3V regulated supply inputs. The EV kit
accepts a positive input between 0.7V and V
OUT
and
converts it to a higher, pin-selectable output voltage.
Efficiency is up to 87% with output load currents to 4A.
This EV kit operates at a fixed 600kHz PWM frequency,
allowing the use of a small inductor.
A movable jumper on the EV kit selects either a 3.3V or
5V output voltage. Additional pads on the board
accommodate the resistors for output adjustment. This
EV kit uses surface-mount components and is fully
assembled and tested for quick evaluation.
♦
0.7V to V
OUT
Input Voltage Range
♦
Pin-Selectable 3.3V or 5V Output Voltage
(5V as Shipped)
♦
Adjustable Output Voltage
(2.5V to 5.5V, External Divider)
♦
Up to 4A Output Current
♦
600kHz PWM Operation
♦
Internal 10A MOSFET Switch
♦
4µA IC Shutdown Current
♦
Surface-Mount Components
♦
Fully Assembled and Tested
Features
Evaluates: MAX1709
Component List
DESIGNATION QTY
C1, C2
2
DESCRIPTION
150µF, 6.3V low-ESR capacitors
Sanyo 6TPB150M or
Panasonic EEFUE0J151R
150µF, 6.3V, 15m
Ω
low-ESR capacitors
Panasonic EEFUE0J151R
Not installed
0.22µF ceramic capacitor (1206)
1µF, 16V ceramic capacitor (1206)
Taiyo Yuden EMK316BJ105KL
TDK C3216X7R1C105M
0.1µF ceramic capacitors (1206)
10A Schottky diode (DPAK)
Central Semiconductor CSHD10-45L
ON Semiconductor (Motorola)
MBRD1035CTL or
STM-Microelectronics STPS8L30B
2-pin headers
1µH, 10A power inductor
Coilcraft DO3316P-102HC or
Coiltronics UP2B-1R0
Not installed
2Ω ±5% resistor (1206)
1MΩ ±5% resistors (1206)
MAX1709EUI 28-pin TSSOP-EP
Shunts
MAX1709 PC board
MAX1709EV kit data sheet
MAX1709 data sheet
Ordering Information
PART
MAX1709EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
28-Pin TSSOP-EP*
C4, C5
C6
C7
C8
C9, C10, C12
2
0
1
1
3
*Exposed
pad.
D1
1
Component Suppliers
SUPPLIER
Central Semiconductor
Coilcraft
Coiltronics
Dale- Vishay
ON Semiconductor
(Motorola)
Panasonic
Sanyo
STM- Microelectronics
Sumida
Taiyo Yuden
PHONE
516-435-1110
708-639-6400
561-241-7876
402-564-3131
602-303-5454
714-373-7939
619-661-6835
617-259-0300
847-956-0666
408-573-4150
FAX
516-435-1824
708-639-1469
561-241-9339
402-563-6418
602-994-6430
714-373-7183
619-661-1055
617-259-9442
847-956-0702
408-573-4159
JU1, JU2, JU3
L1
R1, R2, R3
R4
R5–R8
U1
None
None
None
None
3
1
0
1
4
1
3
1
1
1
Note:
Please indicate that you are using the MAX1709 when
contacting these component suppliers.
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAX1709 Evaluation Kit
Evaluates: MAX1709
Quick Start Reference
The MAX1709 EV kit is fully assembled and tested.
Follow these steps to verify board operation.
Do not turn on the power supply until all connec-
tions are completed:
1) Connect a voltmeter to the VOUT pad.
2) Connect a 3V supply to the VIN pad. Connect
ground to the GND pad.
3) Remove all the shunts from JU1, JU2, and JU3. Turn
on the power supply and verify that the output voltage
is 5V. Refer to the MAX1709 data sheet for output
load during startup.
4) For other output voltages, refer to the
Setting the
Output Voltage
section in the MAX1709 data sheet
for instructions on selecting feedback resistors R1
and R2.
Detailed Description
The MAX1709 EV kit provides a pin-selectable 3.3V or
5V output from a 0.7V to V
OUT
input voltage. The output
voltage can also be adjusted with external resistors for
voltages between 2.5V and 5.5V.
The MAX1709 includes an internal MOSFET switch with
a typical peak current limit of 10A and can deliver loads
up to 4A. Connecting an external resistor from SS/LIM
to GND (R3) can also reduce the current limit.
Connecting a capacitor from SS/LIM to GND (C10) sets
the soft-start rate.
The EV kit operates at a 600kHz switching frequency
and allows the use of a small inductor value. The
switching frequency can also be synchronized to an
external clock ranging from 350kHz to 1MHz.
Jumper Selection
Three jumpers on the PC board allow user selection of
several configurations. Table 1 lists the jumpers and
their functions.
Table 1. Jumper Functions
JUMPER
JU1
JU2
SHUNT
LOCATION
Not installed
Installed
Not installed
Installed
Not installed
JU3
PIN CONNECTION
ONB
connected to GND
ONB
connected to VOUT
ONA connected to GND
ONA connected to VOUT
3.3/5
connected to VOUT
3.3/5
connected to GND
Installed
3.3/5
connected to GND
and resistors R1, R2 are
installed
MAX1709 OPERATION
MAX1709 is enabled if ONA = VOUT.
MAX1709 is disabled if ONA = GND.
MAX1709 is disabled if
ONB
= VOUT.
MAX1709 is enabled if
ONB
= GND.
VOUT is set to 5V. FB pin must be connected to ground (R2 = short).
VOUT is set to 3.3V. FB pin must be connected to ground (R2 = short).
VOUT = adjustable between 2.5V to 5.5V. Refer to the
Setting the
Output Voltage
section in the MAX1709 data sheet for instructions on
selecting feedback resistors R1 and R2. Also cut PC trace shorting R2.
2
_______________________________________________________________________________________
VIN
VOUT
L1
1µH
JU1
28
ONB
LX3
LX2
LX2
1
ONA
LX1
3
2
23
22
21
20
19
18
15
17
C9
0.1µF
R4
2Ω
R6
1MΩ
LX1
PGND3
27
CLK/SEL
PGND3
PGND2
PGND2
6
SS/LIM
PGND1
OUT
NC
13
REF
FB
11
GND
NC
3.3/5
26
GND
25
1
JU3
14
NC
24
R8
1MΩ
VOUT
2
16
C7
0.22µF
NC
NC
C10
0.1µF
9
10
PGND1
LX1
4
C4
150µF
6.3V
C5
150µF
6.3V
C6
OPEN
C8
1µF
16V
5
C12
0.1µF
6
D1
VOUT
5V AT 4A
7
LX3
R5
1MΩ
8
GND
C1
150µF
6.3V
C2
150µF
6.3V
Figure 1. MAX1709 EV Kit Schematic
U1
MAX1709
R1
OPEN
R2
SHORT
(PC TRACE)
GND
ONB
VOUT
JU2
ONA
VOUT
R7
1MΩ
CLK
R3
OPEN
Evaluates: MAX1709
_______________________________________________________________________________________
REF
1.25V
MAX1709 Evaluation Kit
3
MAX1709 Evaluation Kit
Evaluates: MAX1709
1.0"
1.0"
Figure 2. MAX1709 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX1709 EV Kit PC Board Layout—Component Side
1.0"
Figure 4. MAX1709 EV 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
© 2005 Maxim Integrated Products, Inc.
Printed USA
is a registered trademark of Maxim Integrated Products.
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