Monolithic Power Systems Inc. MP6540HGU-A-Z

Overview

MP6540HGU-A-Z from Monolithic Power Systems is a three-phase brushless DC motor driver IC integrating six N-channel power MOSFETs, pre-drivers, gate drive power supplies, and bidirectional current-sense amplifiers. It delivers 5A continuous / 6A peak output current, supports 5.5V–50V input voltage, and features internal charge pump for 100% duty cycle operation in BLDC motor control systems for HVAC blowers and power tools.

For engineers reviewing the MP6540HGU-A-Z datasheet, MP6540HGU-A-Z pinout, MP6540HGU-A-Z application, or MP6540HGU-A-Z equivalent, key selection criteria include its QFN-26 (5mm×5mm) package thermal performance, synchronous rectification behavior, fault reporting via open-drain nFAULT, and compatibility with microcontroller PWM or HS/LS logic interfaces.

Technical Context

The MP6540HGU-A-Z implements three independent half-bridge drivers with integrated high-side and low-side MOSFETs (R_DS(on) = 25mΩ HS + 20mΩ LS at 25°C), enabling trapezoidal or sinusoidal commutation. Its internal charge pump generates V_CP ≈ VIN + 5.5V to sustain high-side gate drive under 100% duty cycle conditions.

It integrates bidirectional current-sense amplifiers (gain ≈ 1/9200 A/A) with SOA/SOB/SOC outputs referenced to V_REF, and employs automatic synchronous rectification triggered by Sx node voltage excursions below GND or above VIN to minimize body-diode conduction losses during inductive flyback.

Key Specifications

Pinout & Package

MP6540HGU-A-Z is housed in a thermally enhanced QFN-26 (5mm × 5mm) package with exposed thermal pad. The 26-pin layout supports three-phase motor connection, dual-mode logic interface (PWM/EN or HS/LS), current sensing, fault signaling, and charge pump management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6540HGU-Z, the -A-Z variant offers identical performance with differentiated top marking for lot traceability; versus DRV8305PWP, MP6540HGU-A-Z reduces component count and layout complexity but trades off programmability and advanced diagnostics.

Availability

MP6540HGU-A-Z is available at Aetrix Electronics and suitable for HVAC blower control, cordless power tool motor drives, and e-bike mid-drive systems requiring stable component supply, consistent top marking, and QFN-26 thermal reliability.

Supply support for MP6540HGU-A-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 MP6540H series belongs to MPS's integrated motor driver product line, designed specifically for compact, efficient three-phase BLDC control in cost-sensitive and thermally constrained applications such as appliances and portable equipment.

FAQ

What is the function of the nSLEEP pin on MP6540HGU-A-Z?

The nSLEEP pin is an active-low input that places the device into ultra-low-power sleep mode when driven logic low. In this state, all gate drivers, current sensors, and internal regulators are disabled, reducing quiescent current to ≤3.5µA. The device wakes up within ~1ms after nSLEEP returns high, and resumes normal operation once internal start-up delay completes.

How does the MP6540HGU-A-Z implement automatic synchronous rectification?

When both high-side and low-side MOSFETs are off and the SA/SB/SC node voltage drops below GND (inductive flyback), the low-side FET turns on until current decays near zero. If the node rises above VIN, the high-side FET activates instead. This replaces lossy body-diode conduction with controlled FET switching, improving efficiency by up to 5% at 5A load.

Can MP6540HGU-A-Z operate with 100% duty cycle? How is this achieved?

Yes - MP6540HGU-A-Z supports true 100% duty cycle operation using an internal charge pump that generates V_CP ≈ VIN + 5.5V. This voltage sustains high-side gate drive even when the high-side FET is continuously on, eliminating reliance on external bootstrap capacitors and enabling full-voltage output without dead-time-induced voltage droop.

What external components are mandatory for MP6540HGU-A-Z operation?

Mandatory components include: (1) 1µF X7R ceramic capacitor between VCP and VIN; (2) 100nF X7R ceramic capacitor between CP1 and CP2; (3) 4.7µF–10µF X7R ceramic capacitor between VG and GND; (4) external pull-up resistor on nFAULT; and (5) termination resistors on SOA/SOB/SOC referenced to V_REF. All must be placed adjacent to respective pins per MPS layout guidelines.

What is the current-sense accuracy and how is it calibrated?

The current-sense amplifier has a nominal gain of 1/9200 A/A (±13% over temperature), with typical offset <±100µA. Accuracy is factory-trimmed and does not require user calibration; output current scales linearly with LS-FET current. For voltage output, use Equation VSOUT = VREF + (ILOAD × RTERM)/9200, where RTERM sets full-scale range (e.g., 5kΩ yields 0–5V for ±3A).

Does MP6540HGU-A-Z support both trapezoidal and sinusoidal commutation?

Yes - MP6540HGU-A-Z is agnostic to commutation method. Its six independent gate drive channels accept PWM or HS/LS logic inputs, enabling implementation of either six-step trapezoidal control (via simple MCU GPIO) or sinusoidal FOC (using high-resolution PWM and current feedback from SOA/SOB/SOC). No internal commutation logic is embedded.

What thermal derating applies to the 5A continuous rating?

The 5A continuous rating assumes θ_JA = 22.4°C/W on a 4-layer PCB with 2oz copper and thermal vias under the exposed pad. At ambient 85°C and T_J(MAX) = 125°C, maximum allowable power dissipation is 1.78W, limiting practical continuous current to ~4.2A. Derate linearly above 85°C ambient or with reduced copper area.