MAX1640EVKIT Maxim Integrated, MAX1640EVKIT Datasheet - Page 2

• Manufacturer Part Number: MAX1640EVKIT
• Description: Power Management IC Development Tools MAX1640/41 Eval Kit
• Manufacturer: Maxim Integrated
• Series: MAX1640, MAX1641r

Note: Please indicate that you are using the MAX1640 when
contacting these component suppliers.
The MAX1640 EV kit is fully assembled and tested.
Follow these steps 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
2) Connect the input power supply (26V max) to the
3) Connect the battery terminals to the 2-pin power
4) Turn on the power supply to the board, and use a
The MAX1640 EV kit is a switch-mode current source
that uses a hysteretic current-mode, step-down, pulse-
width-moduled (PWM) topology with constant off time.
The switching mechanism is controlled by internal com-
parators that monitor the current through a sense resis-
tor (R1 or R2) and the voltage at TERM. When the
inductor current reaches the current limit, the P-channel
FET turns off, and the N-channel FET synchronous rec-
tifier turns on. Inductor energy is delivered to the load
MAX1640 Evaluation Kit
2
_________________________Quick Start
______________Component Suppliers
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AVX
Coilcraft
Coiltronics
Dale-Vishay
International Rectifier
IRC
Motorola
Nihon
Sanyo
Siliconix
Sprague
Sumida
Vishay/Vitramon
charged by placing the shunt across J3, pins 1
and 6. The MAX1640 EV kit is shipped configured
for six cells and 1.5A of charge current.
2-pin power connector J1. The input supply must
be 1V greater than the maximum battery-charging
voltage and capable of providing the charge cur-
rent.
connector J2. Observe the polarity markings.
voltmeter to confirm the voltage across the battery.
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as the current ramps down at a rate controlled by a
resistor from TOFF to ground (R3) and the inductor
value. When the off time expires, the P-channel FET is
turned back on, and the N-channel FET is turned off.
Switch SW1 controls the two digital inputs, D0 and D1,
that select between four possible current levels (see
Table 1).
In pulse-trickle mode, the switch is on for 12.5% of the
period set by R3, resulting in a lower current for trickle
charging. Refer to the Programming the Output
Currents section in the MAX1640/MAX1641 data sheet
for instructions on selecting the current levels.
Selection of the maximum charge voltage (number of
cells) in the MAX1640 EV kit is made via a voltage
divider selected by J3. Place the shunt across the J3
pins to select the desired number of cells as indicated
by the silkscreen on the board. Refer to the section
Setting the Maximum Output Voltage Level in the
MAX1640/MAX1641 data sheet for instructions on
selecting the resistor-divider values. The EV kit is
shipped configured for a maximum charge voltage of
12V (six cells). Refer to Table 2 for the selectable J3
options.
Table 1. Charge-Current Levels (SW1)
Table 2. Jumper J3 Functions
D1
0
0
1
1
SHUNT LOCATION
Selecting the Output Current Levels
1 and 6
2 and 5
3 and 4
D0
0
1
0
1
Selecting the Number of Cells
0A, current off
0.375A, top-off charge
0.5A at 12.5% duty cycle,
trickle charge
1.5A, fast charge
OUTPUT CURRENT
NUMBER OF CELLS
(User-defined R11)
6 (12V)
2 (4V)