Monolithic Power Systems Inc. MP6540AGU-Z

Overview

MP6540AGU-Z from Monolithic Power Systems is a 3-phase brushless DC motor driver IC integrating six N-channel MOSFETs, pre-drivers, charge-pump gate drive, and bidirectional current sense amplifiers. It delivers 3A continuous / 10A peak output across 5.5V–35V supply, supports 100% duty cycle via internal charge pump, and features UVLO, thermal shutdown, and over-current protection. Used in compact BLDC motor control for drones and power tools.

For engineers reviewing the MP6540AGU-Z datasheet, MP6540AGU-Z pinout, MP6540AGU-Z application, or MP6540AGU-Z equivalent, key selection factors include its QFN-26 (5mm×5mm) package, HS/LS input logic (MP6540A variant), integrated current sensing with ±3A range, synchronous rectification, and fault reporting via open-drain nFAULT.

Technical Context

The MP6540AGU-Z implements independent high-side and low-side logic inputs per phase (HSA/LSA, HSB/LSB, HSC/LSC), enabling precise commutation control without external PWM generation. Its internal charge pump generates VCP = VIN + 5.5V to sustain high-side gate drive at 100% duty cycle, while the trickle-charge circuit maintains regulation under sustained conduction.

Current sensing uses matched internal amplifiers with 1/9200 typical current-to-voltage ratio referenced to VREF, delivering ±103–125µA output per ±1A load current. Fault handling includes deglitched OCP (0.4µs) with 10ms auto-retry, thermal shutdown at 150°C with 25°C hysteresis, and UVLO with 250mV hysteresis.

Key Specifications

Pinout & Package

MP6540AGU-Z is housed in an FCQFN-26 package (5.0mm × 5.0mm, 0.5mm pitch) with exposed thermal pad. Pin mapping follows MPS QFN-26 top-view layout with pin 1 marked by index area.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar three-phase BLDC motor driver applications.

Compared with MP6540AGU-Z, MP6530AGU-Z sacrifices current sensing and voltage headroom for cost reduction, while TMC6300-LA trades simplicity for configurability and higher pin count - MP6540AGU-Z remains optimal for fixed-function, space-constrained BLDC drives needing analog current feedback.

Availability

MP6540AGU-Z is available at Aetrix Electronics and suitable for drone propulsion systems, cordless power tools, industrial HVAC fans, and medical infusion pumps requiring stable component supply and long-term production continuity.

Supply support for MP6540AGU-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 power management ICs, with design centers in the US, China, and Taiwan.

The MP65xx series targets compact, efficient BLDC motor control - engineered for integration density, thermal resilience, and analog current feedback in space- and power-constrained applications.

FAQ

What is the difference between MP6540 and MP6540A variants?

The MP6540AGU-Z uses separate high-side (HSA/HSB/HSC) and low-side (LSA/LSB/LSC) input pins per phase, enabling direct GPIO control of each FET. The MP6540GU-Z uses PWM/Enable pairs (PWMA/ENA, etc.) and requires external logic for 6-step commutation. Both share identical MOSFETs, protection, and package.

Can MP6540AGU-Z operate at 100% duty cycle? How is this achieved?

Yes. MP6540AGU-Z sustains 100% high-side conduction using an internal charge pump that generates VCP = VIN + 5.5V. A 100nF capacitor between CP1–CP2 and a 1µF capacitor from VCP to VIN maintain gate voltage - verified in datasheet Figure 1 and Electrical Characteristics table.

What external components are mandatory for basic operation?

Mandatory components include: 1µF/10V ceramic capacitor from VCP to VIN, 100nF/≥VIN ceramic capacitor between CP1–CP2, 4.7µF/10V ceramic capacitor from VG to GND, and external pull-up on nFAULT. LSS must be directly connected to GND per Pin Functions table.

How does the current sense amplifier work, and what is its accuracy?

The amplifier senses only low-side FET current with 1/9200 typical ratio (±13% min/max variation). At ±1A load, it outputs ±103–125µA into a termination resistor (RTERM), producing a voltage shift from VREF per Equation (1) - calibrated across -40°C to +125°C per Typical Characteristics plots.

Does MP6540AGU-Z support automatic synchronous rectification? How does it improve efficiency?

Yes. When both HS and LS FETs are off and SA/SB/SC voltage drops below GND or rises above VIN, the corresponding LS or HS FET turns on briefly. This replaces body-diode conduction with active FET conduction, reducing forward voltage drop from ~0.7V to ~0.1V and cutting freewheeling losses by >60%.

What thermal derating applies at elevated ambient temperatures?

With θJA = 22.4°C/W on a 4-layer PCB, continuous current drops from 3A at 25°C ambient to ~1.8A at 85°C ambient (per TJ = TA + θJA × PD; PD = I² × RDS(on)). Derating curves are shown in Figure 11 of the datasheet, confirming 1.5A at 105°C ambient.

Is the nFAULT pin actively driven or open-drain?

nFAULT is an open-drain output requiring an external pull-up resistor (typically 10kΩ to 5V or 3.3V). It asserts low during UVLO, thermal shutdown, or OCP events and releases high-Z when faults clear - confirmed in Pin Functions table and Operation section.