Monolithic Power Systems Inc. MP6535GU-Z

Overview

MP6535GU-Z from Monolithic Power Systems is a three-phase BLDC motor pre-driver IC with integrated 500mA buck regulator and 120° Hall-sensor commutation logic. It drives six external N-channel MOSFETs across 5V–55V input, supports 100% duty-cycle high-side operation via trickle-charged bootstrap, and delivers 0.8A source / 1A sink gate drive per phase. Used in e-bike controllers and power drills for precise motor speed/direction/brake control.

For engineers reviewing the MP6535GU-Z datasheet, MP6535GU-Z pinout, MP6535GU-Z application, or MP6535GU-Z equivalent, key selection criteria include its integrated buck regulator output (10–12.8V), programmable short-circuit protection via OCREF, adjustable dead-time control (30ns to 6µs), and thermal shutdown at 150°C - all critical for robust motor drive design under variable load and voltage conditions.

Technical Context

The MP6535GU-Z implements a regulated charge pump generating ~11.5V at VREG for low-side gate drive, while high-side drive relies on bootstrap capacitors replenished by an internal 5µA trickle-charge circuit - enabling continuous conduction without gate voltage collapse. Its 120° commutation engine accepts three Hall sensor inputs (HA/HB/HC) and interprets direction (DIR), PWM speed modulation, and active-low braking (nBRAKE) to sequence six gate outputs.

Protection architecture includes dual over-current mechanisms: V_DS-based short-circuit detection referenced to OCREF (0.125–2.4V range), and LSS-shunt-based OCP with 0.5V threshold and 53–80µs fixed off-time. Fault reporting occurs via open-drain nFAULT, latched until reset by nSLEEP or VIN UVLO recovery.

Key Specifications

Pinout & Package

MP6535GU-Z uses a thermally enhanced 40-pin QFN package (5mm × 5mm) with exposed thermal pad for efficient heat dissipation in motor drive applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6535GU-Z, MP6532GU-Z reduces integration but improves thermal margin in compact layouts, while TBD7200AFNG offers higher voltage tolerance at the cost of increased design complexity and loss of autonomous Hall commutation.

Availability

MP6535GU-Z is available at Aetrix Electronics and suitable for e-bike motor controllers, cordless power tools, industrial blowers, and automated door actuators requiring stable component supply across automotive-grade temperature ranges (-40°C to +125°C).

Supply support for MP6535GU-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, motor control, and LED drivers.

The MP6535 belongs to MPS's BLDC pre-driver product line, engineered specifically for cost-sensitive, thermally demanding motor applications where integration of gate drive, commutation logic, and local regulation reduces system footprint and firmware overhead.

FAQ

What is the maximum continuous output current capability of the integrated buck regulator?

The MP6535GU-Z buck regulator delivers up to 500mA continuous output current at its VREG pin. This is specified across the full input range (5V–60V) and ambient temperatures (–40°C to +125°C), with typical output voltage of 10–12.8V. The regulator uses current-mode control with 330–570kHz switching frequency and includes foldback protection during short-circuit events.

How does the trickle-charge circuit enable 100% duty-cycle operation?

The trickle-charge circuit supplies ~5µA of continuous current to each bootstrap capacitor during high-side conduction, compensating for leakage and ESR losses that would otherwise discharge the capacitor. This maintains sufficient gate-source voltage (V_GS) on the high-side MOSFET even when the complementary low-side FET remains off indefinitely - a requirement for field-oriented control (FOC) and certain braking modes.

Can the MP6535GU-Z operate without Hall sensors?

No - the MP6535GU-Z requires three Hall sensor inputs (HA/HB/HC) to execute its hardwired 120° commutation logic. It does not support sensorless back-EMF detection or alternative commutation methods. If Hall-less operation is needed, a different pre-driver (e.g., MP6540) or MCU-based solution must be used.

What is the purpose of the OCREF pin, and how is it configured for over-current protection?

The OCREF pin sets the voltage threshold for both V_DS-based short-circuit detection and LSS-shunt-based over-current protection. Applying 0.5V to OCREF configures OCP to trigger when shunt voltage exceeds 0.5V (e.g., 10A through 50mΩ). Connecting OCREF to VREG disables both protections. A resistor divider from VREG to GND allows precise threshold programming across the 0.125–2.4V range.

Is the nFAULT output latched or auto-recovering after a fault event?

The nFAULT output is latched: once asserted low due to UVLO, OCP, short-circuit, or thermal shutdown, it remains low until the fault condition is cleared *and* the device is reset via either cycling nSLEEP (low→high) or allowing VIN to drop below UVLO threshold and recover. This ensures persistent fault signaling for system-level safety monitoring.

What thermal management considerations apply to the QFN-40 package?

The MP6535GU-Z QFN-40 (5mm×5mm) has θ_JA = 36°C/W and θ_JC = 8°C/W on a 4-layer PCB per JESD51-7. To maintain T_J ≤ 125°C at full load, the exposed thermal pad must be soldered to a minimum 250mm² copper pour with ≥4 thermal vias (0.3mm diameter) to inner ground planes. Ambient temperature and airflow significantly impact achievable power dissipation.

Does the MP6535GU-Z support PWM frequency scaling for acoustic noise reduction?

Yes - the MP6535GU-Z's gate driver operates synchronously with the external PWM input signal, which can be varied from DC up to the system MCU's maximum output frequency (typically ≤20kHz). While the internal charge pump and buck oscillator frequencies are fixed (110kHz and ~450kHz respectively), the commutation timing follows the applied PWM, enabling audible-noise optimization by shifting switching above 20kHz.