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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Battery Chargers

Monolithic Power Systems Inc. MP2681GS-Z

Name: MP2681GS-Z
Brand: Monolithic Power Systems Inc.
SKU: MP2681GS-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MP2681GS-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Battery Chargers

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: MP2681GS-Z.pdf

Description:: IC BATT CHG LI-ION 1CELL 16SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MP2681GS-Z from Monolithic Power Systems is a highly integrated Li-ion/Li-polymer switch-mode battery charge controller for power tool chargers, featuring automatic 3S–5S battery cell detection via ID resistor, precision CC/CV regulation (4.15 V/cell ±25 mV), pre-charge mode (150 mA), and full fault protection including NTC monitoring, timer-based safety cutoff, and open-drain FLT fault signaling.

For engineers reviewing the MP2681GS-Z datasheet, MP2681GS-Z pinout, MP2681GS-Z application in power tool cradle chargers, or MP2681GS-Z equivalent for multi-cell Li-ion CC/CV control with integrated status indication and thermal safety - this device delivers single-chip AC adapter–to-battery charging with programmable charge rate, LDO-powered peripheral biasing, and dual LED status signaling.

Technical Context

The MP2681GS-Z implements a dual-loop analog control architecture: one op-amp (COMP) manages voltage regulation by driving an optocoupler in flyback primary-side feedback, while a second op-amp (IFB path) handles current limiting via external sense resistor comparison against programmable VIREF (0.16 V fast / 0.016 V slow). Battery configuration (3S1P–5S2P) is determined by VID voltage at the ID pin, which selects internal resistor dividers to set both V_BATT regulation (12.45 V to 20.75 V) and corresponding pre-charge/recharge thresholds.

Thermal safety is enforced through continuous NTC voltage monitoring on the NTC pin, with four defined voltage windows (VT1–VT4) mapping to temperature ranges and dynamically scaling charge current-e.g., full I_CHG between VT2–VT3, reduced to I_CHG/4 below VT2. A dedicated TMR pin sets oscillator frequency (15 Hz with 0.1 µF) to govern fixed pre-charge timers (60/90 min) and scalable total charge timers (2–12 hr), all backed by hardware-level CCON gate drive shutdown on fault.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4.5 V to 30 V - supports universal AC adapter inputs and enables direct integration with wide-range flyback controllers.
Battery Regulation Voltage	4.15 V/cell ±25 mV - precise CV termination for Li-ion cells across 3S–5S configurations, ensuring safe full-charge without overvoltage stress.
Pre-charge Current	150 mA - fixed low-current mode for deeply discharged batteries (<3.0 V/cell), preventing lithium plating during recovery.
Charge Termination Threshold	10% of programmed I_CHG - configurable current cutoff ensures reliable end-of-charge detection independent of battery capacity.
LDO Output	5.0 V ±0.2 V @ 20 mA - powers NTC divider, ID resistor network, and FLT pull-up, eliminating need for external bias supply.
NTC Monitoring Windows	Four voltage thresholds (VT1–VT4) - maps directly to battery temperature range (0°C–60°C) and scales charge current in real time.
Timer Accuracy	±20% over temperature - hardware-based timing ensures fail-safe charge duration limits even under MCU-free operation.

Pinout & Package

MP2681GS-Z is housed in a 16-pin SOIC package (SOIC16), optimized for surface-mount assembly in compact cradle charger PCBs and compatible with standard reflow profiles (lead-free, RoHS-compliant).

Pin/Terminal	Circuit Role	Design Meaning
1 VDD	Power supply input	Bypassed with ≥4.7 µF capacitor; powers internal circuitry and LDO; UVLO triggers at 4.5 V.
3 GND	Ground reference	Common return for analog and power sections; critical for stable feedback loop operation.
4 VFB	Voltage feedback input	Connects to optocoupler cathode; regulates output voltage by comparing divided battery voltage to internal 2.075 V reference.
5 COMP	Combined voltage/current loop output	Drives optocoupler LED; shared node for CC and CV error amplifiers; requires external compensation.
6 IFB	Current feedback input	Monitors voltage across external sense resistor; compares to VIREF (0.16 V or 0.016 V) to enforce constant current.
7 LEDR / 8 LEDG	Bi-color LED drivers	Open-drain outputs supporting back-to-back LED; encode 7 distinct states (charging, full, NTC fault, timer fault, etc.).
9 CR	Charge rate select	Logic high = fast charge (VIREF = 0.16 V); logic low = slow charge (VIREF = 0.016 V); floating defaults to fast.
10 ID	Battery identification input	Detects six VID levels (0.265–4.145 V) to auto-configure 3S–5S topology and regulation voltage.
11 NTC	Temperature sensing input	Reads voltage from NTC/resistor divider; enables dynamic current derating and charge suspension outside safe temp range.
12 TMR	Timer capacitor connection	Connects to GND via capacitor (e.g., 0.1 µF) to set oscillator frequency and charge timing intervals.
13 LDO	5 V regulated output	Supplies bias to NTC, ID, and FLT circuits; delivers up to 20 mA; tracks VDD if <5 V.
14 FLT	Fault indicator output	Open-drain signal pulled low on any fault (NTC, timer, ID, power line); used for system-level fault reporting.
15 BATT	Battery voltage sense	Direct connection to battery pack positive; enables dead-battery detection (<1.0 V/cell) and pre-charge initiation.
16 CCON	Charge path MOSFET gate driver	Active-low output controlling external high-side switch; pulled high on fault to immediately disconnect battery.

Key Features

Feature	Design Value
Auto-detect battery configuration	Identifies 3S1P, 3S2P, 4S1P, 4S2P, 5S1P, or 5S2P via six VID thresholds on ID pin - eliminates manual configuration and enables universal charger design.
Dual-mode charge rate control	CR pin selects fast (0.16 V VIREF) or slow (0.016 V VIREF) charge without changing sense resistor - simplifies firmware-less rate switching.
Integrated 5 V LDO	Provides regulated bias for NTC, ID, and FLT circuits - removes need for external LDO and reduces BOM count in space-constrained tools.
Hardware-enforced safety timers	Fixed pre-charge timer (60/90 min) and scalable total charge timer (2–12 hr) - prevents thermal runaway during abnormal charging conditions.
Multi-state LED status encoding	LEDR/LEDG drive bi-color LED to indicate charging, full, NTC fault, timer fault, ID error, and power line fault - enables intuitive user diagnostics.
Robust fault isolation	FLT pin asserts low and CCON pulls high simultaneously on any fault - guarantees immediate battery disconnection and system-level alerting.

Applications

Power Tool Cradle Charger

Standalone Fast Charger

Use Scenario: Integrated into cordless drill/driver cradle units with AC input and isolated flyback topology.

IC Role / Device Role / Timing Role: Primary CC/CV controller managing battery voltage regulation, current limiting, and automatic 3S–5S topology selection based on pack ID resistor.

Use Value: Enables single-charger compatibility across multiple tool platforms (e.g., 12 V, 18 V, 20 V MAX) without hardware changes or firmware updates.

Use Scenario: Embedded in wall-plug or desktop fast chargers for professional-grade power tools requiring >2 A charge current.

IC Role / Device Role / Timing Role: Core analog charge manager handling pre-charge, CC ramp, CV hold, and termination - coordinated via COMP/IFB loops and CCON gate drive.

Use Value: Delivers full 5S2P (20.75 V, ~4 A) charging with real-time NTC derating and hardware timer backup - eliminating reliance on host microcontroller for safety-critical functions.

Battery Pack Validation System

Industrial Portable Equipment Charger

Use Scenario: Used in production test fixtures to verify battery pack integrity before deployment in field tools.

IC Role / Device Role / Timing Role: ID resistor decoder and fault injector - validates VID voltage accuracy, NTC response, and FLT/CCON fault signaling behavior.

Use Value: Confirms correct battery pack wiring, thermistor calibration, and ID resistor value prior to final assembly - reducing field returns due to mis-matched packs.

Use Scenario: Charging subsystem in ruggedized portable medical or test equipment with removable Li-ion battery packs.

IC Role / Device Role / Timing Role: Autonomous charge supervisor providing LED status, thermal monitoring, and fault-safe shutdown - operates without host processor intervention.

Use Value: Ensures compliance with IEC 62368-1 thermal and electrical safety requirements through hardware-enforced NTC windowing and timer limits.

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-cell Li-ion CC/CV control applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BQ24618RTWR	Requires external microcontroller for battery configuration selection; no integrated VID-based auto-detection; uses SMBus for status reporting instead of LED drivers.	Best suited for systems with existing MCU infrastructure and need for telemetry logging; lacks standalone LED indication and cradle-ready ID resistor interface.	Select when firmware-controlled flexibility outweighs plug-and-play battery compatibility and visual status feedback.
ISL9238HRZ-T	Supports only 3S–4S configurations; no 5S support; integrates buck-boost controller but lacks dedicated CCON gate driver for external MOSFET control.	Ideal for compact USB-PD–compatible chargers where integrated power stage suffices; not suitable for high-power flyback-based cradle designs requiring discrete FETs.	Choose for space-constrained, lower-voltage (≤16.6 V) applications where integrated regulation eliminates need for external PWM controller.

Compared with BQ24618RTWR and ISL9238HRZ-T, MP2681GS-Z uniquely combines hardware-based 3S–5S auto-detection, dual LED status encoding, and dedicated CCON gate drive - making it the only option enabling fully autonomous, visually indicated, cradle-style charging for professional power tools without MCU dependency.

Availability

MP2681GS-Z is available at Aetrix Electronics and suitable for power tool cradle chargers, standalone fast chargers, battery validation systems, and industrial portable equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP2681GS-Z 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 power ICs, with expertise in DC/DC conversion, battery management, and motor control solutions.

The MP2681 belongs to MPS's battery charge controller product line, designed specifically for high-reliability, high-power portable tool charging applications requiring autonomous multi-cell configuration detection and hardware-enforced safety.

FAQ

What battery configurations does MP2681GS-Z support?

The MP2681GS-Z supports six configurations: 3S1P, 3S2P, 4S1P, 4S2P, 5S1P, and 5S2P. It detects these automatically via six predefined VID voltage thresholds (0.265 V to 4.145 V) applied to the ID pin using a battery-pack–integrated resistor divider. Each VID level corresponds to a specific cell count and parallel count, setting both regulation voltage (12.45 V to 20.75 V) and associated thresholds.

How does the MP2681GS-Z handle deeply discharged batteries?

When VBATT falls below 3.0 V/cell, the MP2681GS-Z enters fixed pre-charge mode, delivering 150 mA through the BATT pin while holding the external MOSFET off. The flyback output is regulated to 3.2 V/cell during this phase. A dedicated 60-minute (3S1P/4S1P/5S1P) or 90-minute (3S2P/4S2P/5S2P) timer prevents indefinite pre-charge, and the device exits pre-charge only when VBATT exceeds 3.0 V/cell or the timer expires.

Can MP2681GS-Z 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 preset VID voltages (e.g., 0.64 V for 4S1P) directly to the ID pin. The device compares this voltage to internal references and selects the corresponding battery configuration and regulation voltage - enabling backward compatibility with legacy or non-ID–equipped packs.

What protections are implemented in hardware versus firmware?

All core protections - NTC window monitoring, pre-charge and total charge timers, overtemperature shutdown (150°C), power-line fault detection, ID pin fault detection, and CCON-driven MOSFET cutoff - are implemented in analog/hardware logic. No firmware or external controller is required for safety enforcement, making the MP2681GS-Z suitable for MCU-less charger designs meeting IEC 62368-1 functional safety expectations.

How is LED status indication implemented?

MP2681GS-Z drives two open-drain outputs (LEDR and LEDG) that connect to a bi-color LED in back-to-back configuration. Seven distinct states are encoded: solid green (charging), solid red (charge complete), flashing red + low green (NTC fault), flashing red + low green (timer fault), and others per Table 3 in the datasheet - enabling unambiguous visual diagnostics without external decoding logic.

What is the role of the LDO pin (Pin 13)?

Pin 13 (LDO) provides a regulated 5.0 V ±0.2 V output capable of sourcing up to 20 mA. It powers the NTC voltage divider, ID resistor network, and FLT pin pull-up resistor - eliminating the need for an external bias supply and simplifying layout in cost-sensitive cradle charger designs.

Does MP2681GS-Z support automatic recharge?

Yes. After charge termination, if battery voltage drops below 3.95 V/cell, the MP2681GS-Z automatically restarts the charge cycle - re-enabling CCON, resetting the timer, and re-applying CC/CV profile until the 10% I_CHG termination threshold is met again. This behavior is fully hardware-based and requires no external trigger or control signal.

MP2681GS-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: -

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Battery Chemistry:: Lithium Ion/Polymer

Number of Cells:: 1

Current - Charging:: Constant

Programmable Features:: Timer

Fault Protection:: -

Charge Current - Max:: -

Battery Pack Voltage:: 4.15V

Voltage - Supply (Max):: 30V

Interface:: -

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

MP2681GS-Z FAQ

1.How can I place an order for MP2681GS-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MP2681GS-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MP2681GS-Z reliable?

The price and inventory of MP2681GS-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP2681GS-Z is usually 5 days.

3.What payment methods are accepted for MP2681GS-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP2681GS-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MP2681GS-Z?

MP2681GS-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MP2681GS-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MP2681GS-Z?

For technical support, including MP2681GS-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP2681GS-Z requirements.

6.How does Aetrix verify that MP2681GS-Z is sourced from the original manufacturer or authorized distributors?

All MP2681GS-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MP2681GS-Z meets industry standards.

7.What is the process for return or replacement of MP2681GS-Z?

All MP2681GS-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP2681GS-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MP2681GS-Z part is unused and in its original packaging.

Return procedure for MP2681GS-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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