Monolithic Power Systems Inc. MP2635AGR-Z

Overview

MP2635AGR-Z from Monolithic Power Systems is a 2A synchronous switch-mode single-cell Li-ion/Li-Polymer battery charger with integrated power path management and bidirectional boost OTG functionality. It delivers precision 3.6V/4.2V charge voltage (±0.5%), supports 4.5–6V input, provides up to 91% boost efficiency at 1A, and enables system power delivery from battery during input absence - used in portable power banks and sub-battery systems.

For engineers reviewing the MP2635AGR-Z datasheet, MP2635AGR-Z pinout, MP2635AGR-Z application, or MP2635AGR-Z equivalent, key selection criteria include programmable input current limit (400–3000mA), dual-mode operation logic (charge/boost/sleep), NTC-based battery temperature monitoring, thermal regulation at 120°C, and integrated short-circuit protection with auto-recovery in boost mode.

Technical Context

The MP2635AGR-Z implements a dual-loop control architecture: in charge mode, it concurrently regulates input current (via ILIM pin), battery charge current (via ISET), battery voltage (VBATT_FULL selectable at 3.6V or 4.2V), and junction temperature (120°C thermal regulation). Its power path prioritizes SYS load over battery charging when input current is constrained.

In boost mode, it operates as a synchronous step-up converter with programmable output current limit (via OLIM), 4.2–6V SYS output range, and feedback regulation referenced to 1.2V. Mode transition is determined by PWIN voltage thresholds (0.75–0.85V low, 1.1–1.2V high) and VIN–VBATT differential (>300mV).

Key Specifications

Pinout & Package

MP2635AGR-Z is housed in a 4×4mm QFN-24 package with exposed thermal pad (PGND), optimized for compact portable designs requiring high power density and thermal reliability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell switch-mode battery charger with power path and boost OTG applications.

Compared with BQ25895RTWR, MP2635AGR-Z offers autonomous analog control and integrated NTC monitoring but lacks digital configurability; versus IP5306, it delivers higher efficiency, tighter voltage accuracy, and robust thermal management - making it optimal for safety-compliant portable electronics.

Availability

MP2635AGR-Z is available at Aetrix Electronics and suitable for power bank systems, smartphone secondary battery modules, and wireless earbud charging cases requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP2635AGR-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 core expertise in DC/DC conversion, battery management, and motor control.

The MP2635A belongs to MPS's integrated battery charger product line, designed specifically for space-constrained portable devices needing combined charging, power path, and bidirectional boost functionality without external controllers.

FAQ

What is the function of the VB pin on MP2635AGR-Z?

The VB pin selects the battery full-charge voltage: connecting it to GND sets 3.6V for LiFePO₄ cells, while leaving it floating or pulling it high configures 4.2V for standard Li-ion/Li-Polymer cells. This selection directly determines the constant-voltage (CV) regulation point with ±0.5% accuracy and affects recharge threshold and overvoltage protection levels.

How does MP2635AGR-Z handle input current limiting during charging?

MP2635AGR-Z uses the ILIM pin to set input current limit via an external resistor to GND. As input current approaches the programmed limit (400–3000mA), the IC reduces charge current to prioritize system (SYS) power delivery. This is implemented through an analog current-sense loop that dynamically balances battery charging and load powering without requiring external control logic.

Can MP2635AGR-Z operate without an external inductor?

No. MP2635AGR-Z is a synchronous switch-mode charger requiring an external 2.2µH or 4.7µH inductor connected between SW and ground. The inductor is fundamental to energy transfer in both charge (buck) and boost modes. Omitting it will prevent proper operation and may damage the internal high-side and low-side MOSFETs due to uncontrolled current slew rates.

What happens during a SYS output short circuit in boost mode?

During a SYS short circuit in boost mode, MP2635AGR-Z disables the power stage after 120µs blanking time and enters hiccup mode. It automatically attempts recovery every 500ms. Once the short is removed, normal boost operation resumes without manual intervention - enabled by integrated short-circuit protection and auto-recovery circuitry tied to the OLIM and MODE pins.

Is thermal shutdown triggered at the same temperature as thermal regulation?

No. Thermal regulation begins at 120°C, where the IC linearly reduces charge current to maintain that junction temperature. Thermal shutdown activates only if junction temperature reaches 150°C - a hard safety limit that forces complete device disablement until temperature falls below hysteresis threshold. Both functions use the same on-die thermal sensor but serve distinct protection layers.

How is battery temperature monitored using the NTC pin?

The NTC pin connects to a voltage divider formed by a pull-up resistor from VSYS and an NTC thermistor to GND. The IC compares the resulting voltage against internal high/low thresholds corresponding to 0°C (66% VSYS) and 50°C (35% VSYS). If the voltage falls outside this window, charging halts immediately and resumes only when the voltage returns within bounds - ensuring cell safety across operational temperature range.