MCP73861 Microchip Technology, Inc., MCP73861 Datasheet - Page 19

• Manufacturer Part Number: MCP73861
• Description: Advanced Single or Dual Cell, Fully Integrated Li-ion / Li-polymer Charge Management Controllersthe MCP7386X Family of Devices Are Highly Advancedlinear Charge Management Controllers For Use in Spacelimited,cost-sensitive Applications. The MCP73861 A
• Manufacturer: Microchip Technology, Inc.

Power dissipation with a 5V, ±10% input voltage source
is:
With the battery charger mounted on a 1 in
1 oz. copper, the junction temperature rise is 60°C,
approximately. This would allow for a maximum operat-
ing ambient temperature of 50°C before thermal
regulation is entered.
6.1.1.3
The MCP7386X is stable with or without a battery load.
In order to maintain good AC stability in the Constant
Voltage mode, a minimum capacitance of 4.7 µF is
recommended to bypass the V
capacitance provides compensation when there is no
battery load. In addition, the battery and interconnec-
tions appear inductive at high frequencies. These
elements are in the control feedback loop during
constant voltage mode. Therefore, the bypass capaci-
tance may be necessary to compensate for the
inductive nature of the battery pack.
Virtually any good quality output filter capacitor can be
used, independent of the capacitor’s minimum Effec-
tive Series Resistance (ESR) value. The actual value of
the capacitor and its associated ESR depends on the
output load current. A 4.7 µF ceramic, tantalum or alu-
minum electrolytic capacitor at the output is usually
sufficient to ensure stability for up to a 1A output
current.
6.1.1.4
The MCP7386X provides protection from a faulted or
shorted input, or from a reversed-polarity input source.
Without the protection, a faulted or shorted input would
discharge the battery pack through the body diode of
the internal pass transistor.
6.1.1.5
In the stand-alone configuration, the enable pin is gen-
erally tied to the input voltage. The MCP7386X auto-
matically enters a low-power mode when voltage on
the V
voltage (V
0.23 µA, typically.
6.1.1.6
Two status outputs provide information on the state of
charge. The current-limited, open-drain outputs can be
used to illuminate external LEDs. Refer to Table 5-1 for
a summary of the state of the status outputs during a
charge cycle.
 2004 Microchip Technology Inc.
PowerDissipation
DD
input falls below the undervoltage lockout
STOP
External Capacitors
Reverse-Blocking Protection
Enable Interface
Charge Status Interface
) reducing the battery drain current to
=
5.5V 2.7V
–
BAT
575mA
pin to V
=
2
1.61W
SS
pad of
. This
6.2
For optimum voltage regulation, place the battery pack
as close as possible to the device’s V
It is recommended to minimize voltage drops along the
high current carrying PCB traces.
If the PCB layout is used as a heatsink, adding many
vias in the heatsink pad can help conduct more heat to
the back-plane of the PCB, thus reducing the maximum
junction temperature.
PCB Layout Issues
MCP73861/2
DS21893A-page 19
BAT
and V
SS
pins.