Description
The MCP73871 device is a fully integrated linear
solution for system load sharing and Li-Ion/Li-Polymer
battery charge management with AC-DC wall adapter
and USB port power sources selection. It is also
capable of autonomous power source selection
between input and battery. Along with its small physical
size, the low number of required external components
makes the device ideally suited for portable
applications.
The MCP73871 device automatically obtains power for
the system load from a single-cell Li-Ion battery or an
input power source (AC-DC wall adapter or USB port).
The MCP73871 device specifically adheres to the
current drawn limits governed by the USB specification.
With an AC-DC wall adapter providing power to the
system, an external resistor sets the magnitude of 1A
maximum charge current while supporting up to 1.8A
total current for system load and battery charge
current.
The MCP73871 device employs a constant
current/constant voltage (CC/CV) charge algorithm
with selectable charge termination point. To
accommodate new and emerging battery charging
requirements, the constant voltage regulation is fixed
with four available options: 4.10V, 4.20V, 4.35V or
4.40V. The MCP73871 device also limits the charge
current based on the die temperature during high
power or high ambient conditions. This thermal
regulation optimizes the charge cycle time while
maintaining device reliability.
The MCP73871 device includes a low battery indicator,
a power good indicator and two charge status
indicators that allow for outputs with LEDs or
communication with host microcontrollers. The
MCP73871 device is fully specified over the ambient
temperature range of -40°C to +85°C.

Features
• Integrated System Load Sharing and Battery
Charge Management
- Simultaneously Power the System and
Charge the Li-Ion Battery
- Voltage Proportional Current Control (VPCC)
ensures system load has priority over Li-Ion
battery charge current
- Low-Loss Power-Path Management with
Ideal Diode Operation
• Complete Linear Charge Management Controller
- Integrated Pass Transistors
- Integrated Current Sense
- Integrated Reverse Discharge Protection
- Selectable Input Power Sources: USB Port or
AC-DC Wall Adapter
• Preset High Accuracy Charge Voltage Options:
- 4.10V, 4.20V, 4.35V or 4.40V
- ±0.5% Regulation Tolerance
• Constant Current/Constant Voltage (CC/CV)
Operation with Thermal Regulation
• Maximum 1.8A Total Input Current Control
• Resistor Programmable Fast Charge Current
Control: 50 mA to 1A
• Resistor Programmable Termination Set Point
• Selectable USB Input Current Control
- Absolute Maximum: 100 mA (L)/500 mA (H)
• Automatic Recharge
• Automatic End-of-Charge Control
• Safety Timer With Timer Enable/Disable Control
• 0.1C Preconditioning for Deeply Depleted Cells
• Battery Cell Temperature Monitor
• Undervoltage Lockout (UVLO)
• Low Battery Status Indicator (LBO)
• Power Good Status Indicator (PG)
• Charge Status and Fault Condition Indicators
• Numerous Selectable Options Available for a
Variety of Applications:
- Refer to Section 1.0 “Electrical
Characteristics” for Selectable Options
- Refer to the Product Identification System
for Standard Options
• Temperature Range: -40°C to +85°C
• Packaging: 20-Lead QFN (4 mm x 4 mm)

Applications
• GPSs/Navigators
• PDAs and Smart Phones
• Portable Media Players and MP3 Players
• Digital Cameras
• Bluetooth® Headsets
• Portable Medical Devices
• Charge Cradles/Docking Stations
• Toys