Monolithic Power Systems Inc. MP6540GU-Z

Overview

MP6540GU-Z from Monolithic Power Systems is a 3-phase brushless DC motor driver IC integrating six N-channel MOSFETs, pre-drivers, gate drive power supplies, and bidirectional current sense amplifiers in a single FCQFN-26 (5mm×5mm) package. It delivers 3A continuous and 10A peak output current, supports 5.5V–35V input voltage, and features integrated UVLO, thermal shutdown, and over-current protection. It is used in compact BLDC motor control systems for drones, power tools, and HVAC blowers.

For engineers reviewing the MP6540GU-Z datasheet, MP6540GU-Z pinout, MP6540GU-Z application, or MP6540GU-Z equivalent, key selection criteria include its 3A/10A current capability, internal charge pump enabling 100% duty cycle operation, synchronous rectification logic, three-phase current sensing architecture, and QFN-26 thermal performance under PCB-constrained conditions.

Technical Context

The MP6540GU-Z implements a three-half-bridge topology with independent high-side and low-side gate drivers per phase, using an internal charge pump to generate ~VIN+5.5V for HS-FET gate drive and an LDO-regulated 5.5V VG supply for LS-FETs. Its current sense amplifiers deliver proportional output current (103–125µA at ±1A load) referenced to VREF, with a typical gain of 1/9200 A/A.

Control logic supports two modes: MP6540 mode (PWM + EN per phase) and MP6540A mode (separate HS/LS inputs), both enabled via nSLEEP. Fault handling includes open-drain nFAULT signaling for over-current (10–17A threshold), UVLO (4–5.5V rising threshold), and thermal shutdown (150°C trip with 25°C hysteresis).

Key Specifications

Pinout & Package

MP6540GU-Z is housed in an FCQFN-26 (5.0mm × 5.0mm) package with exposed thermal pad for enhanced heat dissipation. Pin numbering follows standard QFN top-view orientation with Pin 1 marked by index area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6540AGU-Z, the MP6540GU-Z offers simpler PWM-based control but less timing granularity; versus STSPIN32F0A, it provides dedicated analog current sensing and fault signaling at lower BOM cost, though requiring external MCU for commutation.

Availability

MP6540GU-Z is available at Aetrix Electronics and suitable for drone propulsion, cordless power tools, HVAC blowers, and industrial fan controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP6540GU-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, including DC/DC converters, motor drivers, and LED drivers, with global manufacturing and quality certifications.

The MP6540 product line targets compact, thermally constrained BLDC motor applications where integration of gate drivers, current sensing, and protection reduces system size and improves reliability over discrete solutions.

FAQ

What is the maximum allowable PCB temperature rise for continuous 3A operation?

At 3A continuous output per phase with 24V input, the MP6540GU-Z dissipates approximately 0.45W (based on 50mΩ R_DS(on)). With θJA = 22.4°C/W on a 4-layer board, this yields a ~10°C junction-to-ambient rise above ambient. To maintain TJ ≤ 125°C, ambient must stay ≤ 115°C - but derating is recommended above 85°C ambient per Figure 7's R_ON vs. temperature curves.

Can MP6540GU-Z operate with 100% duty cycle on all three phases simultaneously?

Yes. The internal charge pump generates VCP ≈ VIN + 5.5V, sustaining high-side gate voltage indefinitely. This eliminates bootstrap capacitor discharge issues seen in external bootstrap drivers, enabling true 100% duty cycle operation without external components or timing constraints.

How is current sense accuracy affected by temperature?

Current sense ratio varies from 1/10500 to 1/7800 (±15%) over –40°C to +125°C, as shown in Figure 7. At 25°C, typical ratio is 1/9200 (±5%). For precision applications, calibration at operating temperature or use of ratiometric ADC referencing VREF mitigates drift.

What external capacitors are mandatory for stable operation?

Four capacitors are required: (1) 4.7–10µF X7R ceramic from VG to GND; (2) 1µF/10V X7R from VCP to VIN; (3) 100nF X7R between CP1–CP2; (4) local 1µF ceramic at each VIN pin. Omitting any causes gate drive instability, OCP false triggers, or thermal runaway.

Does MP6540GU-Z support sensorless commutation?

No. It provides only phase current sensing (SOx) and fault status (nFAULT), not back-EMF detection or integrated commutation logic. Sensorless operation requires external comparators or MCU-based observers; the IC serves strictly as a controlled 3-phase power stage.

Is the exposed thermal pad electrically connected internally?

Yes. The exposed pad is internally connected to GND and must be soldered to a solid GND plane on the PCB. Thermal resistance drops from 22.4°C/W (θJA) to ~18.4°C/W (θJC) when properly attached, directly impacting safe continuous current capability.

What happens during simultaneous over-current and over-temperature events?

Both conditions trigger nFAULT low and disable all six MOSFETs. The device enters latched-off state for 10ms (OCP retry time), then automatically recovers if faults clear. If either condition persists, repeated 10ms off-cycles occur until root cause is resolved.