Monolithic Power Systems Inc. MP26124GR-Z

Overview

MP26124GR-Z from Monolithic Power Systems is a monolithic step-down switching Li-ion battery charger IC designed for 4-series cell packs, supporting up to 24V input, delivering up to 2A charge current with ±0.75% battery voltage regulation accuracy and fixed 600kHz switching frequency. It integrates a 0.2Ω high-side MOSFET and implements dual-loop (current/voltage) control for precise CC/CV charging in clean robots and drone battery systems.

For engineers reviewing the MP26124GR-Z datasheet, MP26124GR-Z pinout, MP26124GR-Z application, or MP26124GR-Z equivalent, key selection criteria include 4S Li-ion charge profile compliance, NTC-based thermal monitoring capability, programmable safety timer, and QFN-16 package thermal performance in space-constrained portable power designs.

Technical Context

The MP26124GR-Z uses peak-current-mode control with dual compensation pins (COMPI for current loop, COMPV for voltage loop), enabling fast transient response and stable regulation across trickle → constant-current → constant-voltage charge phases. Its internal 3.3V LDO (VREF33) powers external circuitry up to 30mA while supporting thermistor biasing via NTC pin.

It implements cycle-by-cycle over-current protection, thermal shutdown at 150°C, and automatic recharge when battery voltage drops below 4.0V/cell (16.0V). The TMR pin accepts a capacitor to set both trickle-charge timeout (30 min) and total charge timeout (3 hours), with fault recovery triggered by EN toggle or input reapplication.

Key Specifications

Pinout & Package

MP26124GR-Z is housed in a thermally enhanced QFN-16 (4mm × 4mm) package with exposed thermal pad, optimized for PCB heat dissipation in high-power charging applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4S Li-ion switching charger applications.

Compared with BQ24618RTWR and ISL9238HRZ-T, MP26124GR-Z offers superior integration (integrated 0.2Ω MOSFET, 3.3V LDO, and dual-loop compensation) in a smaller QFN-16 footprint, making it optimal for cost-sensitive, space-constrained 4S Li-ion chargers where analog control and thermal robustness are prioritized over digital configurability or ultra-high current.

Availability

MP26124GR-Z is available at Aetrix Electronics and suitable for clean robot battery systems, drone power modules, and industrial handheld scanner designs requiring stable component supply, consistent parametric performance, and long-term lifecycle availability.

Supply support for MP26124GR-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 design centers across Asia and North America and global distribution through authorized partners.

The MP26124 belongs to MPS's battery management IC product line, engineered specifically for high-efficiency, thermally robust switching chargers targeting 2–4 series Li-ion battery packs in portable and robotics applications.

FAQ

What is the maximum supported battery voltage and how is it regulated?

The MP26124GR-Z regulates terminal battery voltage to 16.8V nominal for 4S Li-ion packs, with guaranteed accuracy of ±0.75% (16.67–16.93V) across temperature and line conditions. Regulation is achieved via a dedicated voltage feedback loop using the COMPV pin, which adjusts duty cycle to maintain constant voltage during the CV phase after CC charging completes.

How does the NTC thermistor interface function and what resistor values are recommended?

The NTC pin forms a voltage divider with VREF33 and ground, comparing the resulting voltage against internally trimmed thresholds (64.2–66.2% and 34–36% of VREF33). For standard 10kΩ NTCs covering 0°C–50°C, R3 = 6.49kΩ and R6 = 21.83kΩ set the window; if no NTC is used, both resistors default to 10kΩ to disable thermal protection.

Can MP26124GR-Z charge a fully depleted battery, and what safeguards apply?

Yes - it initiates trickle charging below 12.0V (3.0V/cell) at 10% of the programmed CC current, preventing lithium metal plating. If the battery remains in trickle mode beyond the TMR-set timeout (e.g., 30 minutes), charging terminates and CHGOK goes high until EN or VIN is cycled, avoiding unsafe prolonged low-current stress.

What is the role of the BST and SW pins, and what capacitor value is required?

BST and SW form a bootstrap gate-drive network: a ceramic capacitor (typically 0.1µF X7R) connects BST to SW to generate a floating voltage ~6V above SW, enabling full enhancement of the internal high-side MOSFET. This eliminates need for external high-side driver and ensures reliable 2A switching at 600kHz.

How is charge current programmed, and what tolerance impact does RS1 have?

Charge current is set by sense resistor RS1 using ICHG = 200mV / RS1. With RS1 = 200mΩ, nominal current is 2A. The 200mV sense threshold has ±5% variation, so total current accuracy depends on RS1 tolerance (e.g., 1% resistor yields ~±6% overall ICHG error), requiring tight-tolerance resistors for precision applications.

Does MP26124GR-Z support automatic recharge, and under what condition does it trigger?

Yes - after full-charge termination, the device enters low-power monitoring mode and automatically resumes charging when battery voltage falls below 16.0V (4.0V/cell), with soft-start and timer reset to prevent disruption. This behavior is inherent and requires no external control, ensuring readiness for intermittent usage patterns in portable equipment.