Monolithic Power Systems Inc. MP2605DQ-LF-Z

Overview

MP2605DQ-LF-Z from Monolithic Power Systems is a linear single-cell Li-Ion/Li-Polymer battery charger IC with integrated 28V input surge protection, programmable 200mA–1A constant-current charging, and thermal foldback for PCB-limited thermal environments. It implements trickle-to-CC-to-CV charging with auto-recharge, NTC-based temperature monitoring (0°C to 50°C), and timer-based fault termination. Used in compact portable electronics requiring robust USB/adapter input tolerance and safe battery management.

For engineers reviewing the MP2605DQ-LF-Z datasheet, MP2605DQ-LF-Z pinout, MP2605DQ-LF-Z application, or MP2605DQ-LF-Z equivalent, this page delivers verified electrical parameters, validated QFN10 package mapping, confirmed pin functions, real-world charge profile behavior, and direct alternative part comparisons - all grounded in Monolithic Power's Rev. 1.0 datasheet and official application guidance.

Technical Context

The MP2605DQ-LF-Z employs a linear regulation architecture with internal PMOS pass device, enabling precise 4.20V ±20mV battery voltage regulation and current-programmed CC mode via external R_CHG. Its proprietary VIN surge protection clamps transients up to +28V without external components, while the 7V input OVP with 400mV hysteresis ensures stable operation across 3.5V–6.5V nominal input range.

Charge sequencing is fully autonomous: trickle mode activates below 2.6V (10% I_CHG), transitions to CC at 2.6V, enters CV at 4.2V, and terminates when current drops to 20% I_CHG. Dual timers enforce 32768-cycle trickle timeout and 262144-cycle total charge limit, with CHG/ACOK open-drain status pins providing real-time fault and charge-state feedback.

Key Specifications

Pinout & Package

MP2605DQ-LF-Z is housed in a thermally enhanced 10-pin 3mm × 3mm QFN package with exposed thermal pad (pin 5), optimized for low θ_JA = 50°C/W on 4-layer PCBs. The exposed pad must be soldered to a solid ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and TP4056, MP2605DQ-LF-Z uniquely integrates 28V surge resilience, hardware-enforced thermal/timeout/NCT safety, and resistor-programmable current in a 3mm×3mm QFN - making it optimal for compact, robust portable designs where reliability and component count matter.

Availability

MP2605DQ-LF-Z is available at Aetrix Electronics and suitable for smartphones, digital cameras, portable media players, and Bluetooth headsets requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term lifecycle support.

Supply support for MP2605DQ-LF-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 in the US, China, and Taiwan, and global distribution through authorized partners.

The MP2605 belongs to MPS's battery management IC product line, engineered specifically for space-constrained portable electronics needing integrated surge protection, precise Li-ion charging control, and hardware-enforced safety - without compromising on thermal performance or bill-of-materials simplicity.

FAQ

What is the maximum input voltage the MP2605DQ-LF-Z can withstand without damage?

The MP2605DQ-LF-Z features proprietary internal VIN surge protection rated to +28V absolute maximum, per its Absolute Maximum Ratings table. This allows direct connection to unregulated adapters or automotive USB ports without external TVS diodes. Operation remains functional only within 3.5V–6.5V, but survival up to +28V is guaranteed.

How is charge current programmed, and what resistor value yields 500mA?

Charge current is set by connecting a resistor (R_CHG) from ISET (pin 8) to GND. The relationship is I_CHG = 1700 / R_CHG (mA/kΩ). For 500mA, R_CHG = 1700 / 500 = 3.4kΩ - the datasheet lists 3.3kΩ as the nominal value yielding 448–582mA, aligning with typical tolerance.

Does the MP2605DQ-LF-Z support automatic recharge, and at what voltage does it trigger?

Yes, the MP2605DQ-LF-Z supports automatic recharge. It restarts the full CC→CV cycle when battery voltage drops to 4.0V ±100mV, as specified in the Electrical Characteristics table under "Recharge Voltage Threshold." This occurs after full-charge termination and ensures battery remains topped off without host MCU involvement.

Can the NTC function be disabled, and how?

Yes, the NTC function can be disabled by replacing the NTC thermistor with a fixed 100kΩ resistor from pin 9 (NTC) to GND, as explicitly stated in the Pin Functions section. Leaving the pin floating is prohibited; the fixed resistor maintains bias stability while disabling temperature-based charge inhibition.

What happens if the battery voltage is lower than the input voltage?

If VIN falls below VBATT, the MP2605DQ-LF-Z automatically disables charging to prevent reverse current flow from battery to input - a key protection feature documented in the "Operation" section. This avoids battery drain when the adapter is disconnected or under-voltage, with leakage current limited to <1µA.

Is thermal foldback active during constant-voltage charging?

Yes, thermal foldback operates continuously across all charge phases - trickle, CC, and CV - based on die temperature (105°C–135°C trip range). During CV mode, it dynamically reduces average charge current to maintain junction temperature below thermal shutdown threshold, extending safe charging time without interrupting the profile.

What is the purpose of the TMR pin, and how is its oscillator frequency calculated?

The TMR pin sets the internal oscillator frequency used for both trickle-charge timeout (32768 cycles) and total charge limit (262144 cycles). Frequency is calculated as F_OSC = 11 Hz / C_TMR(µF); with a 2.2µF capacitor, F_OSC = 5 Hz. Shorting TMR to GND disables the timer entirely.