MCP73862 Microchip Technology Inc., MCP73862 Datasheet - Page 19

• Manufacturer Part Number: MCP73862
• Description: Advanced Single Or Dual Cell, Fully Integrated Li-ion / Li-polymer Charge Management Controllers
• 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
Effective 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 aluminum 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
generally tied to the input voltage. The MCP7386X
automatically enters a Low-power mode when voltage
on the V
reducing the battery drain current to 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.
© 2005 Microchip Technology Inc.
PowerDissipation
DD
input falls below the UVLO voltage (V
External Capacitors
Reverse-Blocking Protection
Enable Interface
Charge Status Interface
=
5.5V 2.7V
–
BAT
575mA
pin to V
=
2
1.61W
SS
pad of
STOP
. This
),
6.2
For optimum voltage regulation, place the battery pack
as close as possible to the device’s V
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 backplane of the PCB, thus reducing the maximum
junction temperature.
PCB Layout Issues
MCP73861/2/3/4
DS21893C-page 19
BAT
and V
SS
pins,