19-2967; Rev 3; 9/03
MAX745 Evaluation Kit
General Description
The MAX745 evaluation kit (EV kit) is an assembled and
tested PC board that implements a step-down, switch-
ing power supply designed for charging lithium-ion (Li-
Ion) batteries. The output voltage can be set for one to
four cells. The cell voltage can be set between 4.0V
and 4.4V, with 0.75% accuracy, using standard 1%
resistors. Two LEDs indicate the charging status.
The MAX745 should be used to charge only Li-Ion bat-
tery packs. To charge other types of batteries, use the
MAX1648 or the MAX712/MAX713. To charge SMBus™
smart-battery packs, use the MAX1645/MAX1647/
MAX1667.
o
Charges One to Four Li-Ion Cells
o
Low Heat/High Efficiency
o
300kHz PWM Operation
o
0.75% Overall Accuracy over Temperature
o
6V to 24V Input Voltage Range
o
Proven PC Board Layout
o
Fully Assembled and Tested
Features
Evaluates: MAX745
Component Suppliers
SUPPLIER*
AVX
Dale-Vishay
International Rectifier
IRC
Kemet
Motorola
Murata
Sanyo
Sumida
TDK
PHONE
803-946-0690
402-564-3131
310-322-3331
512-992-7900
864-963-6300
602-303-5454
770-436-1300
619-661-6835
847-956-6835
847-803-6100
FAX
803-626-3123
402-563-6418
310-322-3377
512-992-3377
864-963-6322
602-996-6430
770-436-3030
619-661-1055
847-956-0702
847-390-4405
PART
MAX745EVKIT
Ordering Information
TEMP RANGE
0°C to +70°C
BOARD TYPE
Surface Mount
*Please
indicate that you are using the MAX745 when contact-
ing these component suppliers.
Component List
DESIGNATION
C1
C2, C7, C9,
C12
C3
C4
C5
C6
C8, C10
QTY
1
DESCRIPTION
68µF, 20V, 0.150Ω, low-ESR
tantalum capacitor
AVX TPSE686M020R0150
0.1µF ceramic capacitors
47nF ceramic capacitor
0.22µF ceramic capacitor
4.7µF ceramic capacitor
TDK C2012X5R0J475K
Murata GRM21BR60J475M
Open
150µF, 35V, 0.17Ω, aluminum
electrolytic capacitors
Sanyo 35CV150GX
DESIGNATION
C11
D1, D4, D6
D2
J3, J4
JU1, JU2, JU3
JU4
L1
LED1, LED2
M1
QTY
1
3
1
2
3
1
1
2
1
DESCRIPTION
1000pF ceramic capacitor
3A, 40V, surface-mount
Schottky diodes
Motorola MBRS340T3
1N4148-type signal diode (SOT23)
Banana jacks
3-pin headers
2-pin header
22µH, 2.8A surface-mount inductor
Sumida CDRH125-220
Light-emitting diodes
2A, 30V, 0.080Ω, logic-level, dual,
N-channel FET
International Rectifier IRF7303
4
1
1
1
0
2
SMBus is a trademark of Intel Corp.
________________________________________________________________
Maxim Integrated Products
1
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.
MAX745 Evaluation Kit
Evaluates: MAX745
Component List (continued)
DESIGNATION
R1
R2, R15
R3, R11, R12,
R16
R4, R5, R10
R6, R7
R13
R14
U1
U2
QTY
1
2
4
0
2
1
1
1
1
DESCRIPTION
0.100Ω ±1% sense resistor
Dale WSL-2010-R1F or
IRC LR2010-01-R100F
10kΩ ±5% surface-mount resistors
100kΩ ±1% surface-mount
resistors
Shorted
1kΩ ±5%, surface-mount resistors
8kΩ ±5%, surface-mount resistor
24Ω ±5%, surface-mount resistor
Maxim MAX745EAP
Maxim MAX931CSA
5) Connect a Li-Ion battery pack between BATT and
GND (BATT is positive, GND is negative). The bat-
tery can be connected with the charger off without
causing damage, or it can be connected after
power is applied.
6) Turn on the DC power supply. Fast charging begins
as soon as the battery is connected and the DC
power supply is on.
7) When the STATUS LED turns on, the charger is
operating in current-regulating mode (fast charge).
When the STATUS LED turns off, the charger is
operating in voltage-regulating mode (float charge).
8) When the DONE LED turns on, the charging current
has fallen below the threshold set by R13, indicat-
ing that charging is over. The charger can be shut
down by closing jumper JU4.
_________________________Quick Start
Do not turn on power until all connections are com-
plete. Observe all precautions on the battery manu-
facturer’s data sheet. Use only lithium-ion (Li-Ion)
cells with this charger.
1) Set jumpers JU1 and JU2 to indicate the number of
cells in the battery pack (Table 1).
2) Set jumper JU3 to the 2A position to enable 2A out-
put current (Table 2).
3) Make sure that jumper JU4 is open to enable
charger output.
4) Connect a DC power supply with sufficient power
rating across the VIN and GND banana jacks (VIN
is positive, GND is negative). DC input voltage
should be between 6V and 24V.
_______________Detailed Description
Upon insertion, batteries are fast charged at a constant
current. Batteries enter float charge when the total bat-
tery terminal voltage reaches the voltage limit.
LED2 (STATUS) indicates that the charger is in current-
regulating mode. This signal can be used to detect the
transition from fast charge to float charge.
LED1 (DONE) indicates that the battery current (fast
charge) is below the 1.6A threshold set by R13 = 8kΩ.
The IBAT output pin sources a current that is propor-
tional to the load current, and comparator U2 detects
when that load current exceeds 1.182V. R13 should not
cause the IBAT voltage to exceed 2V under maximum
load current. Refer to the MAX745 data sheet.
Table 1. Configuring Number of
Li-Ion Cells
NUMBER
OF CELLS
1
2
3
4
VOLTAGE
ADJUSTMANT
RANGE
4V–4.4V
8V–8.8V
12V–13.2V
16V–17.6V
JU1
POSITION
1, 2
1, 2
3, 4
3, 4
JU2
POSITION
1, 3
2, 4
1, 3
2, 4
Table 2. Jumper Functions
JUMPER STATE
JU1
JU1
JU2
JU2
JU3
JU3
JU3
JU4
JU4
3, 4
1, 2
2, 4
1, 3
2A
Open
0A
Open
FUNCTION
CELL1 = VL; three or four cells selected.
CELL1 = GND; one or two cells selected.
CELL0 = VL; two or four cells selected.
CELL0 = GND; one or three cells selected.
ISET = REF; output current limited to 2A.
ISET is open; output current limited to 1A.
ISET = GND; output current disabled.
THM = REF; output enabled.
Closed THM = GND; output enabled.
2
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