Microchip Technology MCP73855-I/MF

Overview

MCP73855-I/MF from Microchip Technology is a 10-lead, 3×3 mm DFN-packaged linear lithium-ion/polymer battery charge management controller with integrated P-channel MOSFET pass transistor, reverse blocking protection, and programmable 4.1 V or 4.2 V voltage regulation. It delivers up to 475 mA fast-charge current (PROG = VSS), supports USB-compliant input (4.5–5.5 V), and features automatic preconditioning, safety timers, and thermal regulation for space-constrained portable devices.

For engineers reviewing the MCP73855-I/MF datasheet, MCP73855-I/MF pinout, MCP73855-I/MF application, or MCP73855-I/MF equivalent, key selection criteria include its 10-pin DFN footprint, absence of thermistor monitoring (vs. MCP73853), single STAT1 status output, USB-compatible charge current settings, and precise ±0.5% voltage regulation accuracy across –40°C to +85°C.

Technical Context

The MCP73855-I/MF implements a fully autonomous linear charging algorithm: preconditioning (trickle charge at ~10% of IREG) for deeply depleted cells below 2.7–2.95 V, followed by constant-current fast charge (70–475 mA, set via PROG resistor), then constant-voltage regulation (4.1 V or 4.2 V, selected by VSET logic level) until termination at ~7% of IREG or after 3-hour elapsed timer. It lacks THERM/THREF pins and STAT2 output present in the MCP73853.

Its internal architecture includes UVLO (4.25–4.65 V start), thermal regulation (current scaling above ~125°C), and thermal shutdown at 155°C (10°C hysteresis). All safety timers-preconditioning (45–75 min), fast-charge (1.1–1.9 hr), and elapsed-time (2.2–3.8 hr)-are scaled by a single external capacitor on TIMER pin.

Key Specifications

Pinout & Package

10-lead 3×3 mm DFN package with exposed pad (EP) connected to VSS for thermal and electrical grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP73853-I/MQ, MCP73855-I/MF removes thermistor interface and second status output to reduce size and cost-ideal for cost-sensitive, non-temperature-critical USB chargers. Versus BQ24075RGTR, it lacks power-path and system-power features but offers simpler layout and lower quiescent current in sleep mode (0.28 µA).

Availability

MCP73855-I/MF is available at Aetrix Electronics and suitable for USB-powered portable devices, single-cell Li-ion cradle chargers, digital cameras, and entry-level power banks requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for MCP73855-I/MF 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, and interface ICs, with deep expertise in power management and battery solutions for embedded systems.

The MCP7385X product line was designed specifically for USB-compliant, space-constrained Li-ion/Li-polymer charging in consumer and industrial portable equipment-emphasizing autonomy, safety, and minimal external components.

FAQ

What is the maximum fast-charge current supported by the MCP73855-I/MF?

The MCP73855-I/MF supports a maximum fast-charge current of 475 mA (typical) when the PROG pin is connected directly to VSS. This value is specified across –5°C to +55°C ambient and aligns with USB 2.0's 500 mA limit, making the MCP73855-I/MF suitable for certified USB charging applications without exceeding bus constraints.

Does the MCP73855-I/MF support battery temperature monitoring?

No, the MCP73855-I/MF does not support battery temperature monitoring. Unlike the pin-compatible MCP73853-I/MQ, it omits the THREF and THERM pins and associated comparator circuitry. Temperature sensing must be implemented externally if required; the MCP73855-I/MF relies solely on voltage, current, and timer-based safety mechanisms.

How is the regulated output voltage selected on the MCP73855-I/MF?

The regulated output voltage on the MCP73855-I/MF is selected via the VSET pin: connecting VSET to VSS configures 4.1 V regulation, while connecting VSET to VDD selects 4.2 V. This dual-option design accommodates both coke and graphite anode Li-ion chemistries, and the ±0.5% accuracy ensures compliance with cell manufacturer voltage tolerances.

What happens when the EN pin is pulled low on the MCP73855-I/MF?

When the EN pin is pulled low, the MCP73855-I/MF immediately terminates charging, disables all internal regulators, and enters ultra-low-power sleep mode drawing only 0.28 µA (typical). STAT1 goes OFF, and the internal P-MOSFET turns off-ensuring no current flows to the battery. Reasserting EN high resumes normal operation if all qualification conditions are met.

Can the MCP73855-I/MF be used in standalone applications without a microcontroller?

Yes, the MCP73855-I/MF is designed for fully standalone operation. It autonomously executes preconditioning, constant-current, constant-voltage, and termination phases using only external passive components (PROG resistor, TIMER capacitor, input/output capacitors). Its STAT1 output provides visual status feedback, eliminating the need for host MCU control in basic USB charger designs.