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19-0371; Rev 4; 5/97
MAX2003A Evaluation Kit
General Description
The MAX2003A evaluation kit (EV kit) is a fast charger
and conditioner for NiCd (nickel cadmium) or NiMH
(nickel-metal hydride) rechargeable batteries. It is con-
figured as a switch-mode current regulator, so power
dissipation is reduced compared to linear-regulator
solutions. The MAX2003A IC controls a P-channel
power MOSFET switch, allowing fast-charge currents
up to 2A. Fast-charge termination can be accomplished
by five methods: rate-of-change of temperature, nega-
tive delta voltage, maximum voltage, maximum time,
and maximum temperature.
The MAX2003A EV kit is a fully assembled and tested
surface-mount printed circuit board.
____________________________Features
o
Complete NiCd or NiMH Fast Charger
o
New Pulsed Trickle-Charge Mode (MAX2003A only)
o
Switch-Mode Operation
o
Up to 2A Charge Current
o
Charges 2 to 12 NiCd or NiMH Cells
o
Discharge-Before-Charge Switch
o
Automatic Switchover from Fast-Charge to
Pulsed Trickle/Top-Off Charge
o
Status LEDs
o
Surface-Mount Components
Evaluates: MAX2003/MAX2003A
Ordering Information
PART
MAX2003AEVKIT-SO
TEMP. RANGE
0°C to +70°C
BOARD TYPE
Surface Mount
Component Suppliers
SUPPLIER
Alpha Thermistor
AVX
Central
Semiconductor
Coilcraft
Dale-Vishay
International
Rectifier
Motorola
Nihon
Sanyo
Siliconix
PHONE
(619) 549-4660
(803) 946-0690
(516) 435-1110
(847) 639-6400
(402) 564-3131
(310) 322-3331
(602) 303-5454
(805) 867-2555
(619) 661-6835
(408) 988-8000
FAX
(619) 549-4791
(803) 626-3123
(516) 435-1824
(847) 639-1469
(402) 563-6418
(310) 322-3332
(602) 994-6430
(805) 867-2698
(619) 661-1055
(408) 970-3950
_________________________Quick Start
The MAX2003A 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.
1) Set the number of cells in the battery pack being
charged by placing the shunt across J4 pins (pins
4 and 13), as shown by the silkscreen on the
board. The EV kit is shipped configured for six
cells and 2A of charge current. Check that
jumpers JU1, JU2, and JU3 are configured as
shown in Tables 1 and 2.
2) Connect the input power source (6.5V to 28V) to
the 2-pin power connector J1. The input supply
must be 1V greater than the maximum battery
charging voltage, and capable of providing the
fast-charge current; otherwise, capacitor C13 will
completely charge to V
IN
and terminate the
charge cycle.
3) Connect the battery to the 2-pin power connector
J2. Observe the polarity markings.
4) Turn on the power supply to the board and use a
voltmeter to confirm the voltage across the battery
and the sense resistor.
________________________________________________________________
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.
MAX2003A Evaluation Kit
Evaluates: MAX2003/MAX2003A
Component List
DESIGNATION QTY
C1, C4
C2, C3
C5, C7, C8,
C9, C11, C12
C6, C14
C10
C13
D1
2
2
6
DESCRIPTION
22µF, 10V aluminum electrolytic
capacitors
Sanyo 10CV22GX
0.22µF, 50V ceramic capacitors
0.1µF, 50V ceramic capacitors
47µF, 35V aluminum electrolytic
capacitors
Sanyo 35CV47GX
1000pF ceramic capacitor
1µF, 25V ceramic capacitors
100mA, 30V diode
Central Semiconductor CMPSH-3
Dual LEDs
Digi-Key P507CT-ND or
Panasonic LN2162C13
1A, 30V Schottky diode
Nihon EC10QS03 or
Motorola MBRS130T3
12V zener diode
Central Semiconductor CMPZ5242B
or Motorola MMBZ5242B
3A, 40V Schottky diodes
Nihon NSQ03A04 or
Motorola MBRS340T3
63.4kΩ, 1%, 1/8W resistor
3.48kΩ, 1%, 1/8W resistor
33.2kΩ, 1%, 1/8W resistor
1kΩ, 5%, 1/8W resistors
J3
3
2
1
2
1
1
1
100kΩ, 5%, 1/8W resistors
J4
10kΩ, 5%, 1/8W resistors
0.120Ω, 1%, 1W resistor
Dale WSL-2512-R120-F
200kΩ, 1%, 1/8W resistors
18.2kΩ, 1%, 1/8W resistor
24.9kΩ, 1%, 1/8W resistor
28.7kΩ, 1%, 1/8W resistor
JU1, JU2, JU3
SW1
None
None
None
3
1
4
1
1
3-pin headers
Momentary switch
Digi-Key P8006/7S
Shunts
MAX2003A PC board
MAX2003A data sheet
1
1
J1, J2
2
N1
1
P1
1
DESIGNATION QTY
R16
R17
R18
R20
R23
R24
RT1
RT2
2
1
1
1
1
1
1
1
1
1
1
1
DESCRIPTION
40.2kΩ, 1%, 1/8W resistor
49.9kΩ, 1%, 1/8W resistor
66.5kΩ, 1%, 1/8W resistor
100kΩ, 1%, 1/8W resistor
243Ω, 1%, 1/8W resistor
732Ω, 1%, 1/8W resistor
2.21kΩ, 1%, 1/8W resistor
1.62kΩ, 1%, 1/8W resistor
2A, 30V dual P-FET
Motorola MMDF2P03HD or
Siliconix Si4953DY or
International Rectifier IRF7306
5A, 30V N-FET
Motorola MMSF5N03HD or
Siliconix Si9410DY
100µH, 2.5A inductor
Coilcraft DO3340-104
MAX2003A IC
Maxim MAX2003ACSE
Hex inverter 74HC04
National Semiconductor
MM74HC04M14A or
Texas Instruments SN74HC04D
Voltage regulator
National Semiconductor LM317LM
Thermistor
Alpha Thermistor P1624
2-pin term connectors
Mouser 506-2MV02
3-pin term connector
Mouser 506-2MV03
16-pin header
D2
1
L1
D4
1
U1
1
1
D5
1
U2
1
D3, D6
R1
R2
R3
R4, R8, R9
R5, R6,
R19
R7, R11
R22
R12, R21
R13
R14
R15
2
1
1
1
3
U3
Therm
1
1
2
_______________________________________________________________________________________
MAX2003A Evaluation Kit
_______________Detailed Description
The MAX2003A EV kit is configured as a switch-mode
regulator controlling a P-channel power MOSFET, P1,
as shown in Figure 1. When power is applied, the
MAX2003A goes into reset mode for approximately
1.5sec, and then samples the CCMD and DCMD pins.
Charge status is determined by CCMD and DCMD;
refer to the MAX2003A data sheet for detailed informa-
tion on the operation of these pins. For this EV kit,
CCMD and DCMD are grounded so that fast-charge is
initiated on power-up after the reset cycle.
When the MAX2003A MOD pin (pin 14) goes high, the
power switch (P1) turns on via C13 and U2. Current
starts to ramp up linearly through L1, producing a volt-
age across the sense resistor (R22). This voltage is
delivered to the SNS pin (pin 9) via filter network R4
and C10. When the sense voltage reaches 0.050V
CC
(250mV for V
CC
= 5V), MOD goes low and P1 turns off.
The voltage across the inductor reverses polarity
because of the collapsing magnetic field, causing
catch diode D3 to be forward biased and to deliver cur-
rent from L1 into the battery. The inductor current
ramps down linearly until the sense voltage across R22
reaches 0.044V
CC
(220mV for V
CC
= 5V), causing
MOD to go high and the cycle to repeat itself.
PT1624 (10kΩ at +25°C, negative temperature coeffi-
cient) connected between J2 pin 2 (BAT-) and J3 pin 3
(THERM) is provided with this EV kit to monitor temper-
ature. If this method is used for charge termination,
make sure the thermistor is in contact with the cells.
Refer to the MAX2003/MAX2003A data sheet for infor-
mation on how to select values for the thermistor resis-
tive divider (RT1, RT2) and temperature-control compo-
nents. RT1 and RT2 have been selected for the Alpha
Thermistor to provide a 1°C/minute termination rate.
Evaluates: MAX2003/MAX2003A
Maximum Temperature Termination
The Maximum Temperature Termination method is used
as a safety feature and should not be needed under nor-
mal operation of the charger. When the thermistor
exceeds the maximum temperature limit of the externally
set TCO pin (V
TCO
= 1.72V for V
CC
= 5V in this EV kit
(+50°C)) or the minimum temperature limit of the inter-
nally set low-temperature fault (V
LTF
= 2.0V for V
CC
= 5V
in this EV kit (+10°C)), fast-charge is terminated. In this
case, the TEMP pin is driven low and the TEMP fault red
LED turns on. Refer to the MAX2003A data sheet for
information on how to set the temperature fault limits.
Maximum Voltage Termination
The Maximum Voltage Termination method is another
safety feature of the charger. If the cell voltage mea-
sured at the BAT pin exceeds that at the MCV pin, fast-
charge is terminated. This EV kit has the external resis-
tor divider set to 1.9V (V
CC
= 5V). Refer to the
MAX2003A data sheet for information on how to set the
maximum cell voltage (MCV).
Selecting the Number of Cells
The number of battery-pack cells is selected by a volt-
age divider. Refer to the MAX2003A data sheet for infor-
mation on how to select resistive divider values.
Selection of the number of cells in this EV kit is made via
J4 (pins 4 and 13). Place the shunt across J4 pins to
select the desired number of cells as indicated on the
board. This EV kit is shipped configured for six cells.
Maximum Timeout Termination
The Maximum Timeout Termination is another safety
feature. The timeout time depends on the charge rate
and is set by control signals TM1 and TM2. If the time-
out is reached before any other termination method is
seen, fast-charge is terminated to protect the battery.
Refer to Table 4 in the MAX2003/MAX2003A data sheet
for timeout programming information. Control signals
TM1 and TM2 are programmed via jumpers JU2 and
JU3. This EV kit is shipped configured for a 1C fast-
charge rate with a 90 minute timeout and top-off charge
enabled.
Negative Delta Voltage Termination
The Negative Delta Voltage Termination (-∆V) method
measures a negative voltage change to determine termi-
nation of fast-charge. -∆V detection is enabled (DVEN)
by placing the shunt across JU1 pins 1 & 2 (DVEN to
V
CC
). This EV kit is shipped with DVEN enabled.
Temperature Rate Termination
The Temperature Rate Termination (∆T/∆t) method ter-
minates fast-charge when a particular rate-of-change of
temperature is exceeded. An external Alpha Thermistor
_______________________________________________________________________________________
3
MAX2003A Evaluation Kit
Evaluates: MAX2003/MAX2003A
Discharge-Before-Charge
Initiate the discharge-before-charge function by activat-
ing switch SW1. Once the momentary switch SW1 is
activated, a low on-resistance, N-channel power MOS-
FET turns on, providing a discharge path to the battery.
Simply connect an external discharge resistor (R
DIS
)
between J3 pins 1 & 2. The discharge process contin-
ues until the per-cell voltage drops below 1V. During
the discharge phase, the CHG pin goes low (LED on)
for 1.375sec and high (LED off) for 0.125sec. Fast-
charging begins as soon as conditions allow. Take
extra care not to overheat the battery during discharge.
Observe the power rating of R
DIS
.
Table 1. Jumper JU1 Settings
SHUNT LOCATION
JU1 across pins
1&2
JU1 across pins
2&3
DVEN PIN
STATUS
V
CC
GND
CHARGER
STATUS
DVEN = enabled
DVEN = disabled
Table 2. Jumper JU2 & JU3 Settings
SHUNT LOCATION
JU2 across pins
2&3
JU3 across pins
1&2
TM1 AND TM2 PIN
STATUS
TM1* = GND
CHARGER
STATUS
Fast-charge
rate = C,
Timeout = 90 min,
Top-off charge =
enabled
Charge Status
Two LED indicators show the MAX2003A’s charge sta-
tus. Table 3 summarizes the different charge-status
conditions.
Inductor Selection
The inductor value is not critical to circuit operation.
However, the greater its value the lower the output rip-
ple current. The 100µH Coilcraft DO3340-104 inductor
used on the evaluation board provides low output ripple
current (approximately 30% of fast-charge current) and
has a 2.5A current rating. Refer to the data sheet for
information on how to select inductor value. For lower
current (up to 1A) and lower profile applications, use
Coilcraft’s DO3316-104 inductor (0.215" max height).
TM2* = V
CC
* Refer to the MAX2003A data sheet for more detailed
information on TM1 and TM2 control signals.
Table 3. Charge Status
CHARGE STATE
Fast-Charge
Charge Pending
Discharge-Before-Charge
Charge Complete and
Top-Off
Temperature Fault
LED STATUS
Green LED on
Green LED on for 0.125sec,
off for 1.375sec
Green LED on for 1.375sec,
off for 0.125sec
Green LED on for 0.125sec,
off for 0.125sec
Red LED on
Using the MAX2003
The MAX2003A EV kit can also be used to evaluate the
MAX2003. Besides replacing the IC, the only other
modification is to change the trickle-charge resistor,
(R11) to 130Ω, 2W.
4
_______________________________________________________________________________________
R11
10k
P1A
U3
LM317LM
D4
R7
10k
P1B
D3
D6
R12
200k
1%
VBAT
C13
1µF
C5
0.1µF
VCC
VCC
N1
Si9410
J4
12
14
74HC04
7
2, 4, 6,
8, 10, 12
9
8
6
5
4
3
2
R19
100k
C12
0.1µF
U2
BAT-
1, 3, 5,
16
9, 11, 13
VCC
R10
USER
SELECTABLE
J3-2
DISCH
J3-1
BAT+
RDIS
L1
100µH
1
IN
2
VOUT
3 6 7
C1
22µF
10V
R23
243Ω
1%
ADJ
4
C6
47µF
35V
C14
47µF
35V
D5
12V
R24
732Ω
1%
VIN
D1
CMPSH-3
BAT+
3
3
2
3
2 1
JU3
R9
1k
1
2 1
Figure 1. MAX2003A EV Kit Schematic
BAT-
C4
22µF
10V
NO. OF
CELLS
C2
0.22µF
GND
C3
0.22µF
SW1
DISCH_COMMAND
U1
MAX2003A
1
VCC
D2
GND
JU1
R8
1k
DVEN
R13
18.2k
1%
R15
28.7k
1%
R17
49.9k
1%
R20
100k
1%
JU2
R22
0.12Ω
1%
1W
VCC
C11
0.1µF
R2
3.48k
1%
R3
33.2k
1%
R4
1k
R1
63.4k
1%
VCC
R6
100k
C7
C8
0.1µF 0.1µF
C9
0.1µF
RT1
2.21k
1%
R5
100k
CCMD
2
DCMD
3
DVEN
4
TM1
5
TM2
6
TS
7
BAT
8
VSS
15
DIS
14
MOD
13
CHG
12
TEMP
11
MCV
10
TCO
9
SNS
R14
24.9k
1%
R16
40.2k
1%
R18
66.5k
1%
R21
200k
1%
THERMISTOR
TO BATTERY
PACK
C10
1000pF
VBATT
RT2
1.62k
1%
Evaluates: MAX2003/MAX2003A
_______________________________________________________________________________________
ALL RESISTORS ARE
1
/
8
W AND 5%, UNLESS OTHERWISE NOTED.
5

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