Monolithic Power Systems Inc. MP2681GS

Overview

MP2681GS from Monolithic Power Systems is a highly integrated Li-ion/Li-polymer switch-mode battery charge controller with automatic battery cell detection (3S1P–5S2P), CC/CV regulation, pre-charge mode, NTC-based temperature monitoring, and full fault protection including timer timeout, power line fault, and ID resistor validation. It operates from 4.5V to 30V input and delivers precise 4.15V/cell regulation for power tool battery packs.

For engineers reviewing the MP2681GS datasheet, MP2681GS pinout, MP2681GS application in cordless power tools, or MP2681GS equivalent for multi-cell battery charging systems, this IC provides integrated voltage/current loop control, dual LED status indication, LDO-supplied biasing, and programmable charge timing - all in a 16-pin SOIC package.

Technical Context

The MP2681GS implements dual independent control loops: a voltage regulation loop using VFB/COMP pins with opto-coupler interface, and a current regulation loop via IFB sensing and COMP output. Its internal 5V LDO powers NTC, ID, and FLT circuitry and supports up to 20mA load.

It features automatic battery configuration detection via six VID thresholds on the ID pin (0.265V–4.145V), enabling dynamic selection of charge voltage (12.45V–20.75V) and timer settings (60–12 hr). The CCON gate driver directly controls external MOSFETs for charge path enable/disable during faults or termination.

Key Specifications

Pinout & Package

MP2681GS is housed in a 16-pin SOIC package (SOIC16), with exposed pad not electrically connected. Thermal resistance θ_JA = 80°C/W on 4-layer PCB per JESD51-7.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-cell Li-ion battery charge controller applications.

Compared with BQ24618RTWR and ISL9238HRTZ, MP2681GS offers autonomous battery topology detection and self-contained status indication - reducing firmware dependency and component count in cost-sensitive power tool applications.

Availability

MP2681GS is available at Aetrix Electronics and suitable for cordless power tool battery chargers, standalone fast chargers, and industrial cordless equipment requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for MP2681GS 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, motion control, and automotive applications.

The MP2681GS belongs to MPS's battery management IC product line, designed specifically for high-voltage multi-cell Li-ion charging in portable power tools and industrial equipment - emphasizing integration, reliability, and hardware-based safety.

FAQ

What battery configurations does MP2681GS support?

The MP2681GS supports six configurations: 3S1P, 3S2P, 4S1P, 4S2P, 5S1P, and 5S2P. Detection is performed automatically via six pre-set VID voltage thresholds on the ID pin (0.265V–4.145V), each corresponding to a specific cell count and parallel count. No external programming or MCU is required.

How does MP2681GS handle deeply discharged batteries?

When VBATT falls below 3.0V/cell, MP2681GS enters fixed pre-charge mode, delivering 150mA constant current through the BATT pin while keeping the external MOSFET off. This continues until VBATT exceeds 3.0V/cell or the pre-charge timer (60 or 90 min) expires - ensuring safe recovery of depleted cells.

Can MP2681GS operate without an ID resistor in the battery pack?

Yes. If no ID resistor is present, the charge termination voltage can be manually configured by applying one of six predefined VID voltages (0.265V–4.145V) to the ID pin using an external voltage source or resistor divider - maintaining full functionality without battery-side components.

What protections does MP2681GS provide during charging?

MP2681GS integrates over-temperature shutdown (150°C), NTC-based thermal window enforcement, timer-based pre-charge and total charge timeout, power line fault detection, ID resistor validation, and open-battery detection. All faults trigger immediate CCON high and FLT low assertion, cutting off the charge path and setting output to 3.2V/cell.

How is status indicated on MP2681GS?

Status is conveyed via LEDR and LEDG pins driving a bi-color LED. Distinct flash patterns indicate charging (red off/green flashing), charge completion (red off/green on), NTC fault (red flashing/green off), timer fault (red flashing/green off), ID error (red flashing/green off), and power line fault (red flashing/green off) - enabling intuitive field diagnostics without test equipment.

What is the role of the LDO pin on MP2681GS?

The LDO pin provides a regulated 5.0V ±0.2V output capable of sourcing up to 20mA. It supplies bias voltage to the ID resistor network, NTC voltage divider, and FLT pull-up resistor - eliminating need for external regulators and simplifying system-level power architecture.

Does MP2681GS support automatic recharge?

Yes. When battery voltage drops below 3.95V/cell after full charge, MP2681GS automatically reinitiates charging without external intervention. It resets the reference voltage, asserts CCON low, and resumes the CC→CV cycle until the 10% termination threshold is met again - extending usable runtime in intermittent-use tools.