Microchip Technology MCP73844-840I/MS

Overview

MCP73844-840I/MS from Microchip Technology is a linear lithium-ion/polymer battery charge management controller designed for dual-series-cell packs. It delivers 8.4V ±0.5% regulated output voltage, supports 8.7–12V input range, integrates programmable safety timers (preconditioning, fast-charge, elapsed-time), enables preconditioning of deeply depleted cells, and provides open-drain STAT1 status output for LED indication. It is used in portable medical instruments requiring precise dual-cell charging with thermal qualification.

For engineers reviewing the MCP73844-840I/MS datasheet, MCP73844-840I/MS pinout, MCP73844-840I/MS application, or MCP73844-840I/MS equivalent, key selection criteria include its fixed 8.4V regulation, absence of integrated thermistor monitoring (unlike MCP73842), MSOP-8 package constraints, gate-drive capability for external P-MOSFET, and compatibility with dual-cell Li-ion/LiPo battery systems operating from wall adapters or USB-powered supplies.

Technical Context

The MCP73844-840I/MS implements a three-phase charge algorithm: preconditioning (trickle-charge at ~10% I_REG when V_BAT < 5.7V), constant-current fast-charge (regulated by V_FCS = 110 mV across R_SENSE), and constant-voltage regulation at 8.4V with automatic termination at ~7% I_REG. It uses an external timing capacitor (CTIMER) to scale all safety timers - preconditioning (60 min), fast-charge (1.5 hr), and elapsed-time (3.0 hr) - with no internal temperature sensing circuitry.

Unlike the MCP73842, the MCP73844-840I/MS omits THREF and THERM pins, removing continuous cell temperature monitoring. Its DRV output drives an external P-channel MOSFET in linear mode for current/voltage control, while STAT1 provides open-drain status signaling with defined states: ON during active charging, OFF at completion or disable, and flashing on fault conditions such as timer expiry.

Key Specifications

Pinout & Package

Package: MSOP-8, surface-mount, 3 mm × 3 mm body, 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP73842-840I/MS, the MCP73844-840I/MS removes thermal monitoring to reduce pin count and cost while retaining identical regulation accuracy and timer functionality; versus BQ24075RGTR, it supports higher input voltages and adds preconditioning - critical for field-recovered dual-cell batteries.

Availability

MCP73844-840I/MS is available at Aetrix Electronics and suitable for portable medical monitors, industrial handheld scanners, and ruggedized data loggers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MCP73844-840I/MS 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 battery management ICs with vertical integration and long-product-lifecycle focus.

The MCP7384X family was designed specifically for cost-sensitive, space-constrained linear charging of single- and dual-cell Li-ion/LiPo batteries in portable instrumentation, eliminating the need for external controllers or firmware while maintaining high voltage accuracy and safety compliance.

FAQ

What is the input voltage range supported by the MCP73844-840I/MS?

The MCP73844-840I/MS operates from 8.7V to 12V, with undervoltage lockout activating below 8.60V (stop) and re-enabling above 8.65V (start). This range accommodates common 9V and 12V wall adapters while ensuring stable regulation for dual-series Li-ion packs. Operation outside this range may cause improper charging or device shutdown.

Does the MCP73844-840I/MS support temperature monitoring for battery safety?

No, the MCP73844-840I/MS does not include THREF or THERM pins and lacks integrated temperature monitoring circuitry. It is functionally identical to the MCP73842-840I/MS except for the omission of thermistor bias and sensing functions. For applications requiring cell temperature qualification, the MCP73842-840I/MS or alternative solutions must be used.

How is the fast-charge current programmed on the MCP73844-840I/MS?

The MCP73844-840I/MS sets fast-charge current using an external sense resistor (R_SENSE) between VDD and the external P-MOSFET source. With a fixed 110 mV regulation threshold at the SENSE pin, I_REG = 0.11 V / R_SENSE. For example, a 220 mΩ resistor yields ~500 mA. No DAC, resistor network, or digital interface is required.

What happens when the battery voltage falls below the recharge threshold after full charge?

When V_BAT drops to V_REG − 400 mV (i.e., 8.0V for MCP73844-840I/MS), the device automatically initiates a new charge cycle - provided EN is high, VDD remains above UVLO, and no fault conditions exist. This recharge threshold is fixed and non-adjustable, ensuring consistent top-up behavior across operating temperatures.

Can the MCP73844-840I/MS be used with single-cell Li-ion batteries?

No, the MCP73844-840I/MS is configured exclusively for dual-series-cell Li-ion/LiPo packs with 8.4V regulation. Its input range (8.7–12V), precondition threshold (5.7V), and UVLO thresholds are optimized for two cells in series. Using it with a single-cell pack would result in overvoltage, potential cell damage, and failure to meet safety standards.