Monolithic Power Systems Inc. MP2661GC-XXXX-Z

Overview

MP2661GC-XXXX-Z from Monolithic Power Systems is a fully autonomous, I²C-controlled single-cell Li-ion/Li-polymer battery charger with integrated power path management. It delivers up to 455mA charge current, regulates system output at 4.65V ±0.5%, and features programmable input current limit (85–455mA), battery voltage regulation (3.6–4.545V), and thermal regulation at 120°C. It is designed for space-constrained portable devices requiring simultaneous system power and battery charging.

For engineers reviewing the MP2661GC-XXXX-Z datasheet, MP2661GC-XXXX-Z pinout, MP2661GC-XXXX-Z application, or MP2661GC-XXXX-Z equivalent, key selection criteria include its WLCSP-9 package footprint, I²C-configurable charge parameters (VBATT_REG, ICHG, VIN_MIN), power path behavior under DPM conditions, and integrated NTC-based temperature monitoring with cold/hot window configuration.

Technical Context

The MP2661 implements a direct power path architecture with two independent FETs: a 300mΩ LDO FET between IN and SYS for regulated system supply, and a 100mΩ battery FET between BATT and SYS for bidirectional energy flow. Its charge control loop supports pre-charge (6–27mA), constant-current fast charge (8–535mA), and constant-voltage regulation (±0.5% accuracy at 4.2V/4.35V).

I²C registers (REG00h–REG06h) configure all critical functions: input current limit, minimum input voltage regulation (3.88–5.08V), battery UVLO (2.4–3.1V), safety timer, recharge threshold (120–350mV below VBATT_REG), and junction temperature regulation (120°C). Fault reporting occurs via open-drain INT pin with programmable interrupt sources including thermal shutdown (150°C), OVP, and NTC out-of-range events.

Key Specifications

Pinout & Package

MP2661GC-XXXX-Z is housed in a 1.55mm × 1.55mm WLCSP-9 package with bottom-side ball array. The package supports ultra-compact PCB layouts typical of wearables and smart sensors.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell Li-ion charger with power path applications.

Compared with BQ25618RTWR and MAX77751EWW+T, MP2661GC-XXXX-Z provides the smallest form factor (1.55mm²), lowest quiescent current in battery-disconnect mode (4–5.5µA), and fastest I²C-configurable response to DPM events-making it optimal for size- and efficiency-critical wearables.

Availability

MP2661GC-XXXX-Z is available at Aetrix Electronics and suitable for wearable fitness trackers, smart Bluetooth earbuds, industrial handheld scanners, and medical patch monitors requiring stable component supply across high-mix, low-volume production runs.

Supply support for MP2661GC-XXXX-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 mixed-signal ICs for power management, motor drive, and automotive applications.

The MP2661 belongs to MPS's battery management product line, engineered specifically for ultra-compact, I²C-programmable charging in space-limited portable electronics with stringent thermal and safety requirements.

FAQ

What is the factory-default I²C register configuration for MP2661GC-XXXX-Z?

The default "xxxx" register setting is 0000, corresponding to IIN_LIM = 85mA, VBATT_REG = 4.2V, VIN_MIN = 4.2V, and EN_TERM = 1. These values are stored in OTP memory and can be reprogrammed via I²C after power-up; no external EEPROM is required.

How does the MP2661 handle input source removal during system operation?

When VIN drops below VIN_UVLO (3.8–4.0V), the IN→SYS LDO FET turns off and the BATT→SYS FET activates automatically, allowing the battery to power the SYS rail uninterrupted. This transition occurs within microseconds and sustains VSYS down to VBATT_UVLO (configurable 2.6–3.0V).

Can the NTC thermistor circuit be disabled for non-temperature-sensitive applications?

Yes-NTC monitoring is disabled by writing 0 to REG01h bit[7]; this removes NTC-related fault assertions and allows charging regardless of NTC pin voltage. However, battery temperature protection is then forfeited, and IEC 62368-1 compliance may be invalidated.

What is the maximum allowable system load current supported by the MP2661 in supplement mode?

In battery supplement mode, the MP2661 supports up to 3.2A ISYS (guaranteed by design), limited by the 100mΩ BATT→SYS FET's thermal capability and PCB copper area. At 1A load, typical voltage drop is 100mV; derating is required above 2A ambient temperature >60°C.

Does the MP2661 support USB BC1.2 or proprietary fast-charge protocols?

No-the MP2661 does not negotiate USB BC1.2, QC, or PD protocols. It operates as a fixed-input charger accepting 4.35–5.5V; protocol handling must occur upstream (e.g., in a USB controller or dedicated charger IC) before feeding VIN.

How is the 4.65V system output voltage maintained during heavy charging current?

The 4.65V VSYS_REG is generated by the IN→SYS LDO FET, which remains active during charging. Its 300mΩ RON ensures <150mV dropout at 500mA load; combined with tight feedback loop bandwidth, it rejects ripple from switching noise and maintains regulation within ±0.5%.

Is the WLCSP-9 package compatible with standard reflow profiles?

Yes-the MP2661GC-XXXX-Z WLCSP-9 package is qualified for IPC/JEDEC J-STD-020D moisture sensitivity level 1 and withstands peak reflow temperatures up to 260°C. Recommended profile follows JEDEC MSLE Level 1: ramp-to-peak ≤3°C/s, peak 235–245°C for 40–80s.