Microchip Technology MCP73861T-I/MLG

Overview

MCP73861T-I/MLG from Microchip Technology is a fully integrated linear lithium-ion battery charge management controller for single-cell Li-ion/Li-polymer packs, featuring 4.1V/4.2V selectable voltage regulation, ±0.5% voltage accuracy, up to 1.2A programmable fast-charge current, integrated P-channel MOSFET pass transistor, and reverse-blocking protection in a 16-pin 4×4 mm QFN package.

For engineers reviewing the MCP73861T-I/MLG datasheet, MCP73861T-I/MLG pinout, MCP73861T-I/MLG application, or MCP73861T-I/MLG equivalent, this device supports space-constrained portable designs requiring precise CV/CC charging, thermal monitoring via external NTC/PTC thermistor, automatic preconditioning of deeply depleted cells, and dual LED status indication (STAT1/STAT2) without external FETs or sense resistors.

Technical Context

The MCP73861T-I/MLG implements a three-stage linear charge algorithm-preconditioning (trickle), constant-current (fast), and constant-voltage-with independent safety timers for each phase. It uses internal current sensing and a precision 1.2V reference to achieve ±0.5% voltage regulation accuracy across –40°C to +85°C ambient.

Its analog architecture includes a dedicated thermistor bias reference (VTHREF = 2.55V typ.), dual temperature comparators with hysteresis (VT1 = 1.25V, VT2 = 0.62V), and thermal regulation that dynamically scales charge current above ~100°C while slowing timer clocks to prevent premature termination.

Key Specifications

Pinout & Package

Package: 16-pin, 4 mm × 4 mm QFN (exposed pad), RoHS-compliant, moisture sensitivity level 3.

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 MCP73861T-I/MLG delivers unique value through selectable 4.1V/4.2V regulation, integrated thermistor reference and comparators, dual open-drain status outputs, and reverse-blocking protection - making it the only option among the three qualified for industrial and medical portable devices requiring full JEITA compliance.

Availability

MCP73861T-I/MLG is available at Aetrix Electronics and suitable for smartphone charging circuits, digital camera battery management, portable medical monitors, handheld barcode scanners, and cradle-based charging systems requiring stable component supply and long-term industrial availability.

Supply support for MCP73861T-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 devices, and power management ICs, with global manufacturing and quality certifications including ISO 9001 and AEC-Q200.

The MCP7386X family was designed specifically for space-constrained, cost-sensitive portable electronics requiring fully autonomous, high-accuracy Li-ion charging - emphasizing integration, safety, and minimal external component count.

FAQ

What is the function of the VSET pin on the MCP73861T-I/MLG?

The VSET pin on the MCP73861T-I/MLG selects the regulated battery voltage: connecting VSET to VSS configures 4.1V output for coke-anode cells, while connecting to VDD selects 4.2V for graphite-anode cells. This dual-option design allows one MCP73861T-I/MLG footprint to support two common Li-ion chemistries without changing the bill of materials.

How does the MCP73861T-I/MLG handle thermal regulation during charging?

The MCP73861T-I/MLG reduces charge current above ~100°C die temperature while proportionally slowing its internal safety timers to prevent premature timeout. This adaptive thermal regulation maintains safe operation without interrupting the charge cycle - a key distinction from simple thermal shutdown, which halts charging entirely at 155°C.

Can the MCP73861T-I/MLG be used with dual-cell (8.4V) battery packs?

No - the MCP73861T-I/MLG is strictly for single-cell Li-ion/Li-polymer applications (4.1V/4.2V). Dual-cell support requires the pin-compatible MCP73862 variant, which offers 8.2V/8.4V regulation and different UVLO thresholds. Using MCP73861T-I/MLG on an 8.4V pack would result in undercharging and potential safety violations.

What external components are required for basic operation of the MCP73861T-I/MLG?

Minimum external components for MCP73861T-I/MLG include: a PROG resistor (to set charge current), a 0.1 µF capacitor on TIMER (for safety timers), 4.7 µF ceramic capacitors on VDD and VBAT pins, and optional NTC/PTC thermistor network on THERM/THREF. No external MOSFET, current-sense resistor, or voltage reference is needed due to full integration.

Does the MCP73861T-I/MLG support automatic recharge after battery self-discharge?

Yes - the MCP73861T-I/MLG automatically initiates a new charge cycle when battery voltage falls below the recharge threshold (VRTH = VREG − 100 mV to −300 mV, depending on configuration), provided all qualification conditions (UVLO, temperature, EN high) remain satisfied. This eliminates need for external wake-up circuitry or host MCU intervention.