MAX8725EVKIT Maxim Integrated, MAX8725EVKIT Datasheet - Page 3

• Manufacturer Part Number: MAX8725EVKIT
• Description: Battery Management Evaluation Kit for the MAX8725
• Manufacturer: Maxim Integrated
• Series: MAX1909, MAX8725r

Specifications of MAX8725EVKIT

• Battery Type: Li-Ion, Li-Polymer, NiCd, NiMH, Lead Acid, Universal
• Operating Supply Voltage: 8 V to 28 V
• Charge Safety Timers: No
• Operating Supply Current: 2.7 mA
• Product Type: Charge Management
• Temperature Monitoring: No
• Uvlo Start Threshold: 9.18 V
• Uvlo Stop Threshold: 9.42 V

Before beginning, the following equipment is required:
• DC source to supply the input current to the charger;
• Voltmeter
• Battery pack or load
The MAX8725 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. Observe all pre-
cautions on the battery manufacturer’s data sheet:
1) Set jumper JU1 to indicate the number of cells in
2) Remove the shunt on JU2 to disable the MAX8725.
3) The battery-regulation voltage is set to 4.2V per cell.
4) The charge current is set to 3A. If a different current
5) The source current is set to 5A. If a different current
6) Connect the input current supply across the
7) Connect a battery pack or load between the BATT+
8) Turn on the power supply.
9) Enable the MAX8725 by installing the shunt on JU2.
10) Verify current is being delivered to the battery.
The MAX8725 includes all the functions necessary to
charge Li+ batteries. The EV kit is shipped with a
charge current of 3A and a battery-regulation voltage of
4.2V x the number of cells in the battery pack.
The MAX8725 includes a battery-conditioning feature,
which allows for the relearning of the battery-pack
capacity. For more information on the operation of the
MAX8725, refer to the Detailed Description section of
the MAX1909/MAX8725 data sheet.
Jumper JU1 selects the number of series cells to be
charged. See Table 1 for jumper settings.
this source must be capable of supplying a voltage
greater than the battery-voltage set point and have
sufficient current rating
the battery pack (Table 1).
If a different voltage is required, see the Battery
Regulation Voltage section.
is required, see the Charging Current Limit section.
is required, see the Source Current Limit section.
ADAPTER_IN and PGND pads.
and BATT- pads.
_______________________________________________________________________________________
Detailed Description
Required Equipment
Quick Start
Jumper JU1
Procedure
MAX8725 Evaluation Kit
Jumper JU2 controls the pack-presence PKPRES pin. A
shunt on JU2 enables the MAX8725. Removing the
shunt places the MAX8725 in shutdown mode.
If the battery pack used with the MAX8725 EV kit has a
thermistor, remove the shunt on JU2 and connect the
thermistor to the THRM pad.
Jumper JU3 connects VCTL to LDO. This sets the bat-
tery-regulation voltage to 4.2V x the number of cells.
The battery-regulation voltage can be set between 4.0V
and 4.4V (x the number of cells) by cutting the short
across JU3 and installing resistors at R3 and R4. See the
Battery-Regulation Voltage section for more information.
The default battery-regulation voltage on the MAX8725
EV kit is 4.2V x the number of cells. To set it to a value
between 4.0V and 4.4V (x the number of cells), remove
the shunt on JU1 and install resistors at R3 and R4. Use
the following equation to calculate the resistor values:
Table 1. Jumper Selection
*Default position.
JUMPER
JU1
JU2
JU3
R
3
=
R
POSITION
( shor ted b y
JUMPER
P C tr ace)
Closed*
Closed*
4
C l osed *
Open
Open
Open






9 523
.
Battery-Regulation Voltage



MODE = LDO. Cell count = 4.
MODE = float. Cell count = 3.
PKPRES = GND. MAX8725 enabled.
PKPRES connected to LDO through
10kΩ pullup resistor. The MAX8725 is
disabled unless the battery thermistor
is connected to THRM.
VCTL = LDO. Battery-regulation
voltage set to 4.2V x the number of
cells.
Battery-regulation voltage can be set
between 4V and 4.4V x the number of
cells. Resistors R3 and R4 must be
installed.
CELLS
V
BATT
5 4
.
−
4 223
FUNCTION
.

 +

Jumper JU2
Jumper JU3
1 8
.
−
1






3