Microchip Technology MCP73861-I/SLG

Overview

MCP73861-I/SLG from Microchip Technology is a fully integrated linear lithium-ion battery charge management controller for single-cell Li-Ion/Li-Polymer packs. It delivers ±0.5% voltage regulation at 4.1V or 4.2V, supports up to 1.2A programmable charge current, includes integrated pass transistor and current sense, and operates across –40°C to +85°C in space-constrained portable devices such as MP3 players and cellular telephones.

For engineers reviewing the MCP73861-I/SLG datasheet, MCP73861-I/SLG pinout, MCP73861-I/SLG application, or MCP73861-I/SLG equivalent, key selection considerations include VSET-selectable regulation voltage (4.1V/4.2V), PROG-resistor–programmable fast-charge current, integrated thermal regulation with THERM/THREF temperature monitoring, and dual open-drain STAT1/STAT2 status outputs for direct LED drive.

Technical Context

The MCP73861-I/SLG implements a three-phase linear charging algorithm: preconditioning (trickle-charge at ~10% of IREG when VBAT < VPTH), constant-current fast charge (IREG set via PROG resistor), and constant-voltage regulation (VREG selected by VSET logic level). All phases are governed by independent safety timers (precondition, fast-charge, elapsed-time) scaled by CTIMER capacitance.

It integrates a P-channel MOSFET pass element, reverse-blocking protection, UVLO (4.25–4.65V start, 4.20–4.55V stop), automatic recharge (VRTH = VREG − 100–300 mV), and die-temperature–based thermal regulation that dynamically scales charge current and slows timer progression to prevent premature termination.

Key Specifications

Pinout & Package

Package: 16-pin QFN (4 mm × 4 mm, 0.5 mm pitch), exposed thermal pad. Pin 1 marked by dot; pin numbering follows standard QFN convention (counterclockwise from top-left corner).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear Li-Ion charge management applications.

Compared with BQ24040DRCT and TP4056, the MCP73861-I/SLG provides unique VSET-selectable regulation, higher 1.2A charge current, integrated thermistor interface, and three independently scalable safety timers - making it optimal for robust, field-deployable single-cell Li-Ion systems demanding configurability and safety compliance.

Availability

MCP73861-I/SLG is available at Aetrix Electronics and suitable for MP3 players, cellular telephones, and hand-held instruments requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for production builds.

Supply support for MCP73861-I/SLG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology is a leading provider of microcontrollers, analog, and interface ICs, with deep expertise in power management and battery solutions for embedded and portable applications.

The MCP7386X family was designed specifically for space-constrained, cost-sensitive Li-Ion/Li-Polymer charging applications - delivering full-featured, stand-alone charge control with minimal external components and industry-leading accuracy.

FAQ

What is the function of the VSET pin on the MCP73861-I/SLG?

The VSET pin on the MCP73861-I/SLG selects the regulated battery voltage: connecting VSET to VSS configures 4.1V output, while connecting to VDD configures 4.2V output. This dual-voltage capability allows the MCP73861-I/SLG to support both graphite and coke anode Li-Ion/Li-Polymer cells without external resistive networks or firmware changes.

How does the MCP73861-I/SLG handle thermal regulation during charging?

The MCP73861-I/SLG continuously monitors die temperature and begins reducing charge current above ~110°C. Unlike simple thermal shutdown, this regulation maintains charging while preventing overheating. The safety timers are also slowed proportionally to avoid premature termination - ensuring reliable operation in thermally constrained enclosures where the MCP73861-I/SLG is deployed.

Can the MCP73861-I/SLG be used with a dual-cell battery pack?

No - the MCP73861-I/SLG is designed exclusively for single-cell Li-Ion/Li-Polymer batteries (4.1V/4.2V output). For dual-series cell applications requiring 8.2V/8.4V regulation, Microchip specifies the pin-compatible MCP73862. Using the MCP73861-I/SLG with a dual-cell pack would result in undercharging and failure to reach full capacity.

What is the maximum recommended charge current for the MCP73861-I/SLG?

The MCP73861-I/SLG supports a maximum fast-charge current of 1.2A, achieved when the PROG pin is connected directly to VSS. This value is confirmed in the DC Characteristics table (IREG = 1020–1380 mA, typical 1200 mA) and is thermally sustainable in the 4×4 mm QFN package with proper PCB copper area and airflow.

Does the MCP73861-I/SLG require external MOSFETs for battery charging?

No - the MCP73861-I/SLG integrates a P-channel MOSFET pass transistor, eliminating the need for external switching elements. This integration reduces solution size, simplifies layout, and ensures matched thermal behavior between control circuitry and power stage - a key advantage over controller-only ICs like the MCP73831.