Microchip Technology MCP73871-1AAI/ML

Overview

MCP73871-1AAI/ML from Microchip Technology is a fully integrated linear Li-Ion/Li-Polymer battery charge management IC with system load sharing, supporting dual input sources (USB or AC-DC adapter), ±0.5% voltage regulation at 4.20 V, 1.8 A total input current limit, and thermal regulation. It powers portable electronics while autonomously prioritizing system load over battery charging via Voltage Proportional Current Control (VPCC).

For engineers reviewing the MCP73871-1AAI/ML datasheet, MCP73871-1AAI/ML pinout, MCP73871-1AAI/ML application, or MCP73871-1AAI/ML equivalent, key selection considerations include its 20-pin QFN package, resistor-programmable fast charge current (50 mA–1 A), selectable USB/AC input current limits, integrated reverse discharge protection, and battery temperature monitoring via NTC thermistor interface.

Technical Context

The MCP73871-1AAI/ML implements a constant-current/constant-voltage (CC/CV) charge algorithm with four factory-set regulation voltages (4.10 V, 4.20 V, 4.35 V, 4.40 V); this variant is configured for 4.20 V ±0.5%. It employs internal pass transistors with 200 mΩ ON-resistance and integrates VPCC to dynamically throttle charge current when input voltage sags-ensuring uninterrupted system operation during high-load conditions.

Its autonomous power-path management includes ideal diode operation between IN/OUT and VBAT/OUT, enabling seamless source selection without external MOSFETs. The device features dedicated open-drain status outputs (STAT1/LBO, STAT2, PG), thermal shutdown at 150°C, and a safety timer configurable for 4/6/8 hours-disabled in this variant ('A' in second character of part number).

Key Specifications

Pinout & Package

Package: 20-Lead QFN (4 mm × 4 mm) with exposed thermal pad (EP), internally connected to VSS. Requires PCB thermal pad connection for optimal thermal performance and electrical reference stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and MAX1555EUK+T, the MCP73871-1AAI/ML delivers superior system resilience through VPCC-based adaptive charging, integrated thermal regulation, and true load-sharing architecture - making it optimal for mission-critical portable electronics where input source variability and thermal environment are uncontrolled.

Availability

MCP73871-1AAI/ML is available at Aetrix Electronics and suitable for GPS navigation devices, portable medical monitors, and Bluetooth headsets requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MCP73871-1AAI/ML 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 Inc. is a leading provider of microcontrollers, analog components, and battery management solutions, serving automotive, industrial, and consumer markets with high-reliability silicon and design resources.

The MCP73871 product line delivers fully integrated, single-chip Li-Ion charge controllers with system load sharing - designed specifically for space-constrained portable electronics demanding autonomous power-path management and USB/AC-DC dual-input flexibility.

FAQ

What is the charge voltage setting for MCP73871-1AAI/ML?

The MCP73871-1AAI/ML is factory-configured for a constant-voltage regulation of 4.20 V with ±0.5% tolerance at +25°C. This value is fixed and not user-adjustable; it corresponds to the '1' in the part number suffix, indicating the 4.20 V option among the four available (4.10 V, 4.20 V, 4.35 V, 4.40 V). The MCP73871-1AAI/ML maintains this accuracy across −40°C to +85°C ambient temperature.

Does MCP73871-1AAI/ML support USB compliance out of the box?

Yes, the MCP73871-1AAI/ML supports USB compliance through its SEL and PROG2 pins: when SEL = Low, PROG2 selects either 100 mA (Low) or 500 mA (High) input current limits - matching USB 2.0 unit-load and high-power specifications. The MCP73871-1AAI/ML also enforces undervoltage lockout and automatic recharging behavior aligned with USB power delivery expectations.

How does the Voltage Proportional Current Control (VPCC) function in MCP73871-1AAI/ML?

In the MCP73871-1AAI/ML, VPCC dynamically reduces battery charge current when the IN pin voltage drops below a threshold (typically 1.23 V at VPCC pin), preserving system output voltage. This occurs without interrupting system operation - the battery supplements power as needed. VPCC is enabled by applying ≥1.23 V to the VPCC pin; tying VPCC to IN disables the feature. The MCP73871-1AAI/ML uses this to maintain system stability under weak or high-impedance input sources.

What is the role of the THERM pin on MCP73871-1AAI/ML?

The THERM pin on the MCP73871-1AAI/ML provides a 50 μA bias current for an external NTC thermistor (typically 10 kΩ), enabling real-time battery temperature monitoring. The MCP73871-1AAI/ML compares the resulting voltage against factory-set thresholds (0.25 V and 1.24 V) and suspends charging if the temperature falls outside the safe window. This protects against thermal runaway and ensures compliance with UN38.3 and IEC 62133 standards.

Is the safety timer enabled in MCP73871-1AAI/ML?

No, the safety timer is disabled in the MCP73871-1AAI/ML. The second character of the part number ('A') denotes timer disable; variants with 'B', 'C', or 'D' offer 4-hour, 6-hour, or 8-hour timers respectively. With TE pin held high or floating (not asserted low), the MCP73871-1AAI/ML relies on automatic charge termination (via PROG3) and thermal/fault protections instead of time-based cutoff.