Microchip Technology MCP73861-I/MLG

Overview

MCP73861-I/MLG from Microchip Technology is a fully integrated linear lithium-ion/lithium-polymer battery charge management controller in a 16-pin 4×4 mm QFN package. It delivers ±0.5% voltage regulation accuracy at 4.1V or 4.2V, supports up to 1.2A fast-charge current via PROG pin resistor programming, includes integrated reverse-blocking protection and thermal regulation, and is designed for single-cell portable devices such as MP3 players and digital cameras.

For engineers reviewing the MCP73861-I/MLG datasheet, MCP73861-I/MLG pinout, MCP73861-I/MLG application, or MCP73861-I/MLG equivalent, key selection considerations include its dual voltage-regulation options (4.1V/4.2V), programmable safety timers, preconditioning for deeply depleted cells, thermistor-based temperature monitoring, and automatic end-of-charge control with STAT1/STAT2 status outputs.

Technical Context

The MCP73861-I/MLG implements a three-stage linear charging algorithm: preconditioning (trickle-charge at ~10% of IREG), constant-current fast charge (programmable 100–1200 mA), and constant-voltage regulation (4.1V or 4.2V ±0.5%). It integrates a P-channel MOSFET pass transistor, internal current sense, and UVLO circuitry with VSTART = 4.5V (typ) and VSTOP = 4.4V (typ).

Thermal regulation dynamically scales charge current above ~90°C die temperature, while thermal shutdown suspends charging at 155°C with 10°C hysteresis. The device uses ratio-metric thermistor sensing referenced to THREF (2.55V typ), with upper/lower thresholds at 1.25V and 0.62V, enabling robust cell temperature qualification across –40°C to +85°C ambient.

Key Specifications

Pinout & Package

Package: 16-pin, 4 mm × 4 mm QFN (MLG suffix), exposed thermal pad, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and TP4056, the MCP73861-I/MLG provides unique flexibility in voltage selection (4.1V/4.2V), comprehensive thermal qualification, and autonomous multi-stage control - making it suitable for higher-reliability portable equipment where battery longevity and safety are prioritized.

Availability

MCP73861-I/MLG is available at Aetrix Electronics and suitable for MP3 players, digital cameras, and hand-held instruments requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant packaging.

Supply support for MCP73861-I/MLG 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, and interface solutions for embedded control applications.

The MCP7386X product line was engineered specifically for space-constrained, cost-sensitive portable electronics requiring fully autonomous, high-accuracy Li-ion/Li-Po battery charging with integrated safety features and minimal external components.

FAQ

What voltage options does the MCP73861-I/MLG support, and how are they selected?

The MCP73861-I/MLG supports two precise voltage regulation options: 4.1V and 4.2V, both with ±0.5% accuracy. Selection is made by connecting the VSET pin (Pin 1) to VSS for 4.1V operation or to VDD for 4.2V operation. This configuration allows optimization for different anode chemistries - 4.1V for older coke-anode cells and 4.2V for modern graphite-anode Li-ion/Li-Po cells - ensuring safe and optimal charging performance in the MCP73861-I/MLG.

How is charge current programmed on the MCP73861-I/MLG?

Charge current on the MCP73861-I/MLG is set using an external resistor between the PROG pin (Pin 5) and VSS. The fast-charge current (IREG) ranges from 100 mA (PROG floating) to 1.2 A (PROG tied to VSS), with intermediate values determined by RPROG = (13.2 / IREG) − 12 kΩ. Preconditioning (IPREG) and termination (ITERM) currents scale proportionally at ~10% and ~8% of IREG respectively - all programmable with a single resistor in the MCP73861-I/MLG.

Does the MCP73861-I/MLG support battery temperature monitoring, and how is it implemented?

Yes, the MCP73861-I/MLG supports continuous cell temperature monitoring via an external NTC or PTC thermistor. The THREF pin (Pin 6) supplies a stable 2.55V reference to bias the thermistor network, while the THERM pin (Pin 7) compares the resulting voltage to ratio-metric thresholds (VTHREF/2 and VTHREF/4). This architecture rejects VDD noise and enables precise thermal qualification across –40°C to +85°C - a core safety function of the MCP73861-I/MLG.

What safety timers are included in the MCP73861-I/MLG, and how are they configured?

The MCP73861-I/MLG includes three independent, capacitor-programmed safety timers: precondition (60 min typ), fast-charge (1.5 hr typ), and elapsed-time termination (3 hr typ). All are set using a single timing capacitor (CTIMER) connected from the TIMER pin (Pin 8) to VSS, with period scaling as CTIMER / 0.1 µF. These timers prevent indefinite charging under fault conditions - a critical safeguard implemented in the MCP73861-I/MLG's autonomous charge algorithm.

What package type is used for the MCP73861-I/MLG, and what are its thermal characteristics?

The MCP73861-I/MLG is housed in a 16-pin, 4 mm × 4 mm QFN package with exposed thermal pad (suffix "MLG"). Its thermal resistance is θJA = 37°C/W on a 4-layer JEDEC-standard board under natural convection. This low thermal impedance enables reliable 1.2A operation without forced airflow, and the device includes on-die thermal regulation that scales charge current above ~90°C and thermal shutdown at 155°C - key reliability features of the MCP73861-I/MLG.