Microchip Technology MCP73841T-420I/UN

Overview

MCP73841T-420I/UN from Microchip Technology is a linear lithium-ion/polymer battery charge management controller in 10-pin MSOP package, featuring ±0.5% voltage regulation accuracy at 4.2 V, programmable fast-charge current via external sense resistor, preconditioning for deeply depleted cells, and integrated thermistor-based temperature monitoring. It delivers complete stand-alone charging for single-cell Li-ion packs in portable medical devices.

For engineers reviewing the MCP73841T-420I/UN datasheet, MCP73841T-420I/UN pinout, MCP73841T-420I/UN application, or MCP73841T-420I/UN equivalent, key selection criteria include its 4.2 V fixed regulation voltage, -40°C to +85°C operating range, THREF/THERM temperature sensing interface, DRV-driven external P-MOSFET topology, and safety timers scaled by external 0.1 µF capacitor.

Technical Context

The MCP73841T-420I/UN implements a three-phase charge algorithm-preconditioning (trickle-charge at ~10% of IREG), constant-current fast charge (regulated by VFCS = 110 mV across RSENSE), and constant-voltage regulation (4.2 V ±0.5%). It integrates dual temperature comparators with 2.55 V THREF reference and hysteresis-controlled thresholds (VT1 = 1.25 V, VT2 = 0.62 V) for NTC/PTC thermistor biasing.

Its analog control loop uses internal voltage and current amplifiers with UVLO (VSTART = 4.45 V), automatic power-down on VDD removal, and open-drain STAT1 status output with 7 mA sink capability. All safety timers-precondition (60 min), fast-charge (1.5 hr), and elapsed-time termination (3.0 hr)-are scaled by CTIMER/0.1 µF.

Key Specifications

Pinout & Package

Package: 10-pin MSOP (3 mm × 3 mm, 0.5 mm pitch), thermally enhanced with exposed pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP73831T-2DCI/OT and BQ24075RGTR, the MCP73841T-420I/UN uniquely balances analog simplicity, guaranteed thermal safety via dedicated THREF/THERM, and full stand-alone operation in a 10-pin MSOP-ideal for industrial and medical applications where reliability trumps integration density.

Availability

MCP73841T-420I/UN is available at Aetrix Electronics and suitable for portable medical monitors, handheld test equipment, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +85°C performance.

Supply support for MCP73841T-420I/UN 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 components, and battery management ICs, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The MCP7384X family was designed specifically for space-limited, cost-sensitive linear charging of single- and dual-cell Li-ion/Li-Po batteries, emphasizing high-accuracy regulation, integrated safety timers, and autonomous thermal qualification.

FAQ

What is the exact voltage regulation accuracy of the MCP73841T-420I/UN?

The MCP73841T-420I/UN provides ±0.5% maximum voltage regulation accuracy at 4.2 V over -5°C to +55°C ambient temperature, as specified in the DS21823D datasheet Table 1-1. This tight tolerance ensures compliance with Li-ion cell manufacturer requirements and maximizes cycle life. The MCP73841T-420I/UN achieves this using a precision internal bandgap reference and trimmed amplifier offsets.

Does the MCP73841T-420I/UN support temperature monitoring, and how is it implemented?

Yes, the MCP73841T-420I/UN supports continuous cell temperature monitoring via dedicated THREF (Pin 5) and THERM (Pin 6) pins. THREF supplies a 2.55 V ±0.075 V reference to bias an external NTC or PTC thermistor network, while THERM compares the resulting voltage against upper (1.25 V) and lower (0.62 V) thresholds. This ratio-metric design makes the MCP73841T-420I/UN immune to VDD fluctuations.

What external components are required for basic operation of the MCP73841T-420I/UN?

Basic operation of the MCP73841T-420I/UN requires: (1) an external P-channel MOSFET driven by DRV (Pin 10), (2) a sense resistor (RSENSE) between VDD and MOSFET source to set IREG, (3) a 0.1 µF timing capacitor (CTIMER) from TIMER (Pin 7) to VSS, (4) 4.7 µF bypass capacitors on VDD and VBAT, and (5) optional THREF/THERM network for temperature monitoring. No external op-amps or ADCs are needed.

How does the MCP73841T-420I/UN handle deeply depleted batteries?

The MCP73841T-420I/UN initiates preconditioning when VBAT falls below 2.85 V (VPTH). It delivers a controlled trickle-charge current (~10% of IREG) until VBAT exceeds VPTH or the 60-minute precondition timer expires. This protects Li-ion cells from damage due to high-current charging at low voltage and minimizes MOSFET heating. The MCP73841T-420I/UN asserts STAT1 ON during this phase and flashes on fault.

What is the function of the EN pin on the MCP73841T-420I/UN, and what happens when it is pulled low?

The EN (Enable) pin (Pin 4) controls charge initiation and termination. When pulled high (≥1.4 V), the MCP73841T-420I/UN enables charging; when pulled low (≤0.8 V), it immediately terminates charge, disables DRV output, and reduces quiescent current to 0.25 µA. This allows host MCU or mechanical switch control of charging state and supports low-power sleep modes in battery-powered systems.