Monolithic Power Systems Inc. MP6651GSS-0000-P

Overview

MP6651GSS-0000-P from Monolithic Power Systems is a single-phase brushless DC (BLDC) motor driver IC with integrated Hall-effect sensor, dual power MOSFETs, and configurable commutation logic. It operates from 3.3V to 18V input, delivers 1.5A continuous current in SOIC-8 SL package, supports 2kHz–100kHz PWM speed control, and provides rotor lock detection via open-drain FG/RD pin - used in high-reliability CPU cooling fan systems.

For engineers reviewing the MP6651GSS-0000-P datasheet, MP6651GSS-0000-P pinout, MP6651GSS-0000-P application, or MP6651GSS-0000-P equivalent, key selection considerations include Hall offset angle configurability (±45°), soft-on/off commutation angles (up to 45°), cycle-by-cycle OCP thresholds (1–4A), thermal shutdown recovery behavior, and FG/RD dual-mode functionality (speed indication or rotor lock flag).

Technical Context

The MP6651 implements closed-loop BLDC commutation using an on-die Hall sensor whose output is phase-shifted via programmable HAL_ANG registers (three ranges mapped to PWM duty). Its H-bridge drives OUT1/OUT2 with timing derived from HALL_TRIM, where high HALL_TRIM enables OUT1 switching while holding OUT2 low, and vice versa.

Speed regulation uses input PWM duty cycle to set output duty directly, with DIN_MIN/DO_MIN registers defining startup behavior and SPD_ZERO enabling zero-speed hold. Protection logic includes auto-recovering OVP (19V rising), UVLO (3.3V rising), rotor lock detection (0.6s timeout), and thermal shutdown (160°C trip, 120°C recovery).

Key Specifications

Pinout & Package

MP6651GSS-0000-P is housed in a straight-lead SOIC-8 package (MSL Level 1, Pb-free, RoHS-compliant), with exposed pad not connected internally. Pin functions are validated per MPS MP6651 Rev. 1.0 datasheet Figure 4 and Pin Functions table (page 5).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6651GD-0000-P, MP6651GSS-0000-P trades 0.5A current headroom and 40% higher RDS(ON) for SOIC-8 manufacturability and legacy footprint compatibility; versus DRV10983ZRTVT, it eliminates external Hall components and simplifies firmware by embedding sensor and commutation logic.

Availability

MP6651GSS-0000-P is available at Aetrix Electronics and suitable for CPU cooling fans, server chassis thermal management, and industrial PC heat dissipation requiring stable component supply across multi-year production cycles.

Supply support for MP6651GSS-0000-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 power management ICs, including DC/DC converters, motor drivers, and LED controllers, with design centers in the US, China, and Taiwan.

The MP6651 belongs to MPS's fan driver product line, engineered specifically for intelligent thermal management in computing and communications infrastructure - emphasizing Hall-integrated commutation, robust fault recovery, and factory-programmable motor profiles.

FAQ

What is the maximum allowable voltage on the FG/RD pin?

The FG/RD pin is an open-drain output with absolute maximum rating of –0.3V to +5.5V. It must be externally pulled up to a voltage ≤5.5V (typically VCC or 3.3V logic rail). Exceeding +5.5V risks permanent damage to the internal clamp diode and output transistor.

Can MP6651GSS-0000-P drive a 24V fan?

No. The MP6651GSS-0000-P has a maximum input voltage (VCC) rating of 18V and over-voltage protection threshold of ~19V. Applying 24V will trigger OVP shutdown and may cause latch-up or permanent damage. Use only within 3.3V–18V range per datasheet Section 6.

How is the Hall offset angle configured for different speed ranges?

Hall offset is set via three independent 5-bit registers: HAL_ANG1 (for PWM duty < DIN_HAL_L/64), HAL_ANG2 (for DIN_HAL_L/64 ≤ duty ≤ DIN_HAL_H/64), and HAL_ANG3 (for duty > DIN_HAL_H/64). Each supports 0–45° in 1.4° increments, with direction (leading/lagging) controlled by HAL_FLAG bit.

Does MP6651GSS-0000-P require external current-sense resistors?

No. The MP6651 uses internal MOSFET RDS(ON) sensing for cycle-by-cycle over-current protection. No external sense resistor is needed - OCP threshold is selected digitally via OCP_SEL[1:0] bits (1A/2A/3A/4A), eliminating BOM cost and layout area.

What happens during rotor lock detection and recovery?

When no Hall edge is detected for 0.6s, MP6651 activates rotor lock protection: both low-side MOSFETs turn on to brake the motor, and FG/RD outputs the configured lock flag. After LOCK_SEL-defined retry delay (3.6–8.4s), it attempts automatic restart - no host intervention required.

Is the OSC pin compatible with capacitive timing?

No. The OSC pin requires a precision 20kΩ (1% tolerance) resistor to GND to set the 27kHz switching frequency and digital clock base. Capacitors or RC networks are not supported; deviation from 20kΩ causes fSW drift and Hall angle calculation errors.

Can the soft-start time be disabled?

No. Soft-start is mandatory and configurable from 2.4s to 19.2s via TIME_SS[2:0] bits. There is no register option to bypass it. This ensures controlled inrush current during power-up, protecting both the IC and motor windings from thermal stress.