Monolithic Power Systems Inc. MP26028EQ-LF-Z

Overview

MP26028EQ-LF-Z from Monolithic Power Systems is a linear single-cell Li-ion battery charger IC with integrated 20V input surge tolerance, programmable 85mA–1A constant-current charging, 0.75% battery voltage regulation accuracy at 4.2V, and trickle-charge preconditioning for deeply discharged cells. It delivers charge status (CHG) and AC adapter power-good (ACOK) signals to portable systems including smartphones and digital cameras.

For engineers reviewing the MP26028EQ-LF-Z datasheet, MP26028EQ-LF-Z pinout, MP26028EQ-LF-Z application, or MP26028EQ-LF-Z equivalent, key selection criteria include its 3mm × 3mm QFN10 package, thermal shutdown threshold of 105–135°C, reverse battery current <1µA, 90µA VIN standby current, and programmable IBF termination threshold (10–50% of ICHG).

Technical Context

The MP26028 operates in three sequential charge phases: trickle (10% ICHG below 2.6V), constant-current (CC) up to 1A, then constant-voltage (CV) regulation at 4.2V ±0.75%. Its proprietary CV auto-recharge loop reinitiates charging when VBATT drops 50mV below target, ensuring battery maintenance without external supervision.

Input protection includes overvoltage lockout (6.8–7.2V trip, 400mV hysteresis) and UVLO (<2.5V), while internal thermal protection forces sawtooth current modulation above 105°C-adjustable via SS pin capacitor-to limit die temperature without full shutdown.

Key Specifications

Pinout & Package

MP26028EQ-LF-Z uses a 10-pin 3mm × 3mm QFN package with exposed thermal pad (connected to GND). The package supports high-power dissipation (θJA = 50°C/W on 4-layer PCB) and enables compact layout in space-constrained portable designs.

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, MP26028EQ-LF-Z provides superior battery longevity control via programmable IBF and auto-recharge, 20V surge tolerance eliminating external protection, and dual open-drain status outputs-making it optimal for premium portable devices demanding reliability and long-term cycle life.

Availability

MP26028EQ-LF-Z is available at Aetrix Electronics and suitable for smartphones, digital cameras, and portable medical monitors requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability.

Supply support for MP26028EQ-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.

The MP26028 belongs to MPS's battery management IC product line, engineered specifically for space-constrained portable electronics requiring high-accuracy linear charging, robust input protection, and intelligent charge-state signaling.

FAQ

What is the maximum input voltage the MP26028EQ-LF-Z can withstand without damage?

The MP26028EQ-LF-Z features integrated input surge protection rated for up to 20V DC. This allows it to survive transient overvoltages common in USB and adapter environments without requiring external TVS diodes. Absolute maximum rating is +20V on the IN pin relative to GND; operation outside 3.5V–6.5V input range disables charging but does not damage the IC.

How is the charge termination current (IBF) programmed, and what is its valid range?

IBF is programmed using an external resistor RBF connected from the IBF pin to GND, with RBF constrained to 2×RCHG ≤ RBF ≤ 10×RCHG. This sets IBF as 10–50% of the programmed ICHG value. For example, with RCHG = 2.3kΩ (ICHG ≈ 700mA), RBF = 20kΩ yields IBF ≈ 70mA (10% of ICHG), triggering charge termination when current drops to that threshold in CV mode.

Does the MP26028EQ-LF-Z support automatic recharge, and how does it function?

Yes-the MP26028EQ-LF-Z implements proprietary constant-voltage auto-recharge: when battery voltage drops 50mV below the trimmed 4.2V target (i.e., to 4.15V), the IC automatically reinitiates CV charging without host intervention. This maintains battery readiness and extends usable capacity between charges, especially in intermittently used devices like remote controls or Bluetooth headsets.

What thermal protection mechanism does the MP26028EQ-LF-Z use, and how does it affect charging?

At junction temperatures exceeding 105°C, the MP26028EQ-LF-Z enters thermal protection mode by modulating charge current into a sawtooth waveform instead of shutting down completely. This reduces average current to prevent thermal runaway while sustaining partial charging. The frequency and amplitude of the sawtooth are adjustable via the SS pin capacitor, allowing designers to balance thermal safety and charge speed.

Can the MP26028EQ-LF-Z be used with non-USB input sources such as 12V wall adapters?

Yes-the MP26028EQ-LF-Z accepts input voltages from 3.5V to 6.5V for normal operation, but its 20V absolute maximum rating allows safe interface with higher-voltage sources when paired with an external series resistor or LDO pre-regulator. Direct connection to 12V violates recommended operating conditions and will trigger input overvoltage lockout (6.8–7.2V trip), halting charging until VIN falls within spec.

What is the purpose of the VBIAS pin, and how must it be configured?

The VBIAS pin supplies internal bias voltage for the IC's analog circuitry. It must be configured with a resistive divider: a 500kΩ resistor (R1) from VBIAS to IN, and a 100kΩ resistor (R2) from VBIAS to GND. This creates a stable ~1.0V bias reference. Omitting or misconfiguring this network causes improper operation, including inaccurate voltage regulation and failure to enter CC/CV modes.