Monolithic Power Systems Inc. MP6531AGR-P

Overview

MP6531AGR-P from Monolithic Power Systems is a three-phase brushless DC motor pre-driver IC that controls six external N-channel MOSFETs in half-bridge configuration, supports 5V–60V input voltage, delivers 0.8A source / 1A sink gate drive per high-side output, and integrates bootstrap charge pump with trickle-charge for 100% duty-cycle operation - used in e-bike motor controllers and power tool drivers.

For engineers reviewing the MP6531AGR-P datasheet, MP6531AGR-P pinout, MP6531AGR-P application, or MP6531AGR-P equivalent, key selection criteria include programmable over-current protection via LSS sensing, adjustable dead-time control (0.13–5.7 µs) using external resistor, thermal shutdown at 190°C, and fault reporting via open-drain nFAULT output.

Technical Context

The MP6531AGR-P implements a three-phase gate driver architecture with independent high-side (GHA/GHB/GHC) and low-side (GLA/GLB/GLC) outputs, each driven by dedicated logic inputs (HA/HB/HC and LA/LB/LC). It uses internal VREG-regulated charge-pump (11.5V typical) for low-side drive and bootstrap capacitors + trickle-charge circuit for high-side drive.

Protection logic includes dual-path current sensing: VDS-based short-circuit detection referenced to OCREF (0.125–2.4V), and LSS shunt-based over-current detection with 0.5V threshold; both trigger latched fault state cleared only by nSLEEP toggle or VIN UVLO recovery.

Key Specifications

Pinout & Package

MP6531AGR-P is housed in a thermally enhanced 4mm × 4mm QFN-28 package with exposed thermal pad, optimized for high-power motor drive PCB layouts requiring efficient heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6531AGR-P, DRV8305PWP adds integrated current sensing but lacks adjustable dead-time resistor control, while STSPIN32F0A embeds processing capability at the cost of design flexibility and higher minimum order quantities.

Availability

MP6531AGR-P is available at Aetrix Electronics and suitable for e-bike motor controllers, cordless power tools, and industrial BLDC pump drives requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP6531AGR-P 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 MP6531A product line targets high-efficiency, high-voltage BLDC motor pre-driver applications where discrete MOSFET control, thermal resilience, and flexible protection tuning are critical - especially in portable and battery-constrained systems.

FAQ

What is the maximum allowable continuous power dissipation for MP6531AGR-P at +25°C ambient?

The QFN-28 package supports 2.9W continuous power dissipation at TA = +25°C, based on θJA = 42°C/W and TJ(MAX) = +150°C. Derating is required above +25°C ambient; for example, at +70°C ambient, max power drops to ~1.9W. Thermal pad soldering to a 4-layer PCB with ≥2 in² copper area is essential to achieve rated performance.

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

The internal trickle-charge circuit supplies ~5µA to each BSTx node during high-side conduction, compensating for leakage currents that would otherwise discharge the bootstrap capacitor. This maintains sufficient gate voltage (>10V) on the high-side MOSFET even when the low-side FET remains off indefinitely - enabling true 100% duty cycle without external charge-pump ICs.

Can MP6531AGR-P drive 100V MOSFETs?

No. The absolute maximum rating for SHA/SB/SC pins is +65V, and recommended operating VIN is limited to 60V. Driving 100V MOSFETs risks exceeding voltage ratings during transients or regenerative events. For 100V systems, select gate drivers rated for ≥120V absolute max, such as MPQ6530-AEC1.

What happens when both HA and LA are driven high simultaneously?

The internal logic forces high-impedance (Hi-Z) on both GHA and GLA outputs, disabling conduction in phase A. This prevents shoot-through by ensuring neither high-side nor low-side MOSFET turns on - a hardware-level safety feature independent of external timing control.

Is the nFAULT output compatible with 3.3V microcontrollers?

Yes. nFAULT is an open-drain output with ≤0.5V low-level voltage at 5mA sink current and <1µA leakage when high. A 10kΩ pull-up to 3.3V yields valid logic levels for standard CMOS inputs, and the pin tolerates up to 6.5V, allowing direct interfacing with 5V or 3.3V MCUs without level-shifting.

How is dead time calculated when using a 20kΩ resistor on DT pin?

Using the formula tDEAD(ns) = 70 × RDT(kΩ), a 20kΩ resistor sets dead time to 1.4µs. This value balances shoot-through prevention and conduction loss in typical 20–30kHz PWM motor drives. Measured waveforms confirm consistent 1.4µs delay between GLx turn-off and GHx turn-on edges under load.

Does MP6531AGR-P support 12V-only operation without VREG startup issues?

Yes. VREG rising threshold is 6.8–8.5V, and VIN can be as low as 5V. At VIN = 12V, VREG starts within 850µs and reaches regulation before power-up sequencing completes. The charge pump operates efficiently across the full 5–60V range, making it suitable for 12V automotive accessory or industrial control applications.