Monolithic Power Systems Inc. MP6505DQ-LF-Z

Overview

MP6505DQ-LF-Z from Monolithic Power Systems is a single-phase brushless-DC motor driver IC with 4.5V–16V input range, integrated 370mΩ high-side and 230mΩ low-side MOSFETs, 400mA continuous output current, 1.2V Hall bias regulator, and TSSOP16 (5.0×6.4mm) package - used for CPU fan speed control in desktop/server cooling systems.

For engineers reviewing the MP6505DQ-LF-Z datasheet, MP6505DQ-LF-Z pinout, MP6505DQ-LF-Z application, or MP6505DQ-LF-Z equivalent, key selection criteria include Hall-based commutation support, programmable minimum speed via RMI, locked-rotor protection with automatic recovery, thermal shutdown behavior, and compatibility with 3mV Hall sensor sensitivity.

Technical Context

The MP6505DQ-LF-Z implements Hall-effect sensor feedback for rotor position detection and current limiting, using differential inputs (IN+, IN−) with 3mV minimum sensitivity. Its dual-drive architecture alternates OUT1/OUT2 conduction to generate bidirectional armature current, enabling unidirectional BLDC rotation without external H-bridge logic.

Speed regulation operates across four modes - Minimum Speed, Variable Speed, Full-Speed, and Locked-Rotor Protection - determined by voltage comparisons between VTH, RMI, and COSC oscillator ramp. The CT pin capacitor sets locked-rotor timeout (e.g., 1µF → ~5s), while COSC (100pF typical) sets switching frequency at 30kHz.

Key Specifications

Pinout & Package

MP6505DQ-LF-Z is housed in a thermally enhanced TSSOP16 package (5.0mm × 6.4mm, 0.65mm pitch) with exposed thermal pad connected to P-GND for improved power dissipation (θ_JA = 90°C/W on 4-layer PCB).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6505DQ-LF-Z, MP6500DJ-LF-Z trades Hall bias integration for wider VIN low-end support, while TB6612FNG offers higher drive capability but shifts all control intelligence to the host MCU - making MP6505DQ-LF-Z optimal for cost-sensitive, space-constrained, single-fan applications needing autonomous operation.

Availability

MP6505DQ-LF-Z is available at Aetrix Electronics and suitable for CPU fan control, server chassis cooling, and industrial blower applications requiring stable component supply, RoHS-compliant packaging, and long-lifecycle availability.

Supply support for MP6505DQ-LF-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP6505 belongs to MPS's BLDC motor driver product line, engineered specifically for compact, intelligent cooling solutions in computing and embedded systems - emphasizing integration, protection autonomy, and Hall-sensor-native control.

FAQ

What Hall sensor sensitivity does MP6505DQ-LF-Z support?

The MP6505DQ-LF-Z accepts differential Hall sensor outputs as low as 3mV peak-to-peak on IN+ and IN− pins. This enables use with low-power, high-sensitivity Hall latches common in modern compact fans, eliminating need for external amplification.

How is locked-rotor protection configured and reset?

Locked-rotor detection uses the CT pin capacitor to set timeout duration (e.g., 1µF ≈ 5s). When rotor stalls, RD goes high-impedance and PWM stops. After timeout, ICT2 discharges CT; once voltage drops to VCTL (~1.7V), driver automatically retries commutation.

Can MP6505DQ-LF-Z drive motors without an external Hall sensor?

No - the MP6505DQ-LF-Z requires external Hall-effect sensors for rotor position feedback. It has no sensorless BEMF detection circuitry. The IN+/IN− inputs and HB 1.2V bias are mandatory for proper six-step commutation and current limiting.

What is the purpose of separating P-GND and S-GND pins?

P-GND carries high-current motor return paths and switching noise; S-GND serves low-noise analog circuits (Hall inputs, references, timing). Separating them prevents ground bounce from corrupting Hall sensing and oscillator stability - essential for reliable commutation.

Does MP6505DQ-LF-Z support PWM speed control directly on the VTH pin?

Yes - the VTH pin accepts either DC voltage (0–3V) or PWM signal (up to 20kHz) to set motor speed. Internal filtering converts PWM to equivalent analog voltage; no external RC filter is required for typical fan control frequencies.

What thermal performance can be expected in TSSOP16 package?

With recommended PCB layout (exposed thermal pad soldered to ≥1cm² copper pour), θ_JA is 90°C/W. At 400mA load and 12V input, power dissipation is ~240mW, resulting in ~22°C junction rise above ambient - well within 125°C max operating temperature.

Is input capacitor selection critical for OVP functionality?

Yes - C_IN absorbs commutation energy; insufficient capacitance causes repeated OVP triggering. Datasheet specifies ≥10µF ceramic + bulk electrolytic; undersized C_IN leads to premature shutdown even at nominal 12V input due to localized voltage spikes.