The MCP73831T-4ADI/OT: A Compact Powerhouse for Single-Cell Li-Ion/Li-Polymer Charging

In the realm of portable electronics, efficient and reliable battery charging is paramount. The Microchip MCP73831T-4ADI/OT stands out as a highly integrated, linear charge management controller meticulously designed for single-cell Lithium-Ion or Lithium-Polymer batteries. This device encapsulates a complete charging solution within a minuscule 5-pin SOT-23 package, making it an ideal choice for space-constrained applications such as Bluetooth headsets, portable medical devices, and compact handheld instruments.

The core strength of the MCP73831T-4ADI/OT lies in its precise constant-voltage and constant-current regulation. The controller maintains an accurate constant-voltage of 4.2V with a tolerance of ±0.75%, which is critical for maximizing battery capacity and ensuring long-term cycle life. It also provides a preset constant-charging current, which can be set using a single external resistor, offering designers significant flexibility. The integration of a pass transistor and current sense circuit eliminates the need for external MOSFETs and complex compensation networks, drastically simplifying the board design and reducing the overall bill of materials (BOM).

Beyond its primary charging functions, the IC incorporates several vital safety and user-friendly features. It includes an automatic power-down mode that reduces the supply current to less than 2 µA when the input voltage is removed, preventing battery drain. The built-in thermal regulation is another key safeguard; it autonomously reduces the charging current if the die temperature exceeds approximately 115°C, protecting the device itself from damage due to excessive power dissipation. Status indication outputs are available to drive LEDs, providing a clear visual cue for charging states like "charge in progress" and "charge complete."

The MCP73831T-4ADI/OT is engineered for operation across a wide input voltage range, typically from 4.5V to 6.0V, making it compatible with common USB ports and wall adapters. Its robust design ensures full compliance with the stringent requirements of the JEITA battery charging guidelines, enhancing safety during the charging process.

ICGOODFIND: The MCP73831T-4ADI/OT from Microchip is a quintessential example of high integration meeting robust performance. It delivers a complete, standalone charging solution in an extremely small form factor, simplifying design, accelerating time-to-market, and providing reliable, safe charging for a vast array of compact, single-cell battery-powered products.

Keywords: Li-Ion Charger, Constant-Current/Constant-Voltage, Thermal Regulation, Standalone Charger, SOT-23.