Monolithic Power Systems Inc. MP6505DM-LF-Z

Overview

MP6505DM-LF-Z from Monolithic Power Systems is a single-phase brushless-DC motor driver IC with integrated high-side (370mΩ) and low-side (230mΩ) MOSFETs, 4.5V–16V input range, 400mA continuous output current, and built-in Hall bias (1.2V), locked-rotor protection, and thermal shutdown. It drives CPU cooling fans in personal computers and servers via PWM or analog voltage speed control.

For engineers reviewing the MP6505DM-LF-Z datasheet, MP6505DM-LF-Z pinout, MP6505DM-LF-Z application, or MP6505DM-LF-Z equivalent, key selection criteria include Hall-sensor interface compatibility, programmable minimum speed via RMI, FG/ RD open-collector status outputs, CT-based locked-rotor recovery timing, and TSSOP16 thermal performance under 400mA load.

Technical Context

The MP6505 implements sensor-based commutation using differential Hall inputs (IN+, IN−) with 3mV sensitivity and a dedicated 1.2V HB bias regulator. Its dual-drive architecture uses complementary PMOS/NMOS half-bridges per output stage, controlled by an internal oscillator (30kHz typical, set by COSC capacitor) and current-limit amplifier with gain of 9A/V.

Speed regulation operates across four modes-minimum speed (RMI-referenced), variable speed (VTH-referenced), full-speed (100% duty), and locked-rotor protection (CT capacitor charge/discharge cycle)-with automatic recovery from over-temperature (>175°C shutdown, <155°C resume) and input over-voltage (20V trip, 18V release).

Key Specifications

Pinout & Package

The MP6505DM-LF-Z is housed in a thermally enhanced 16-pin TSSOP package (5.0mm × 6.4mm) with exposed thermal pad connected to P-GND for improved heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6505DN-LF-Z, the MP6505DM-LF-Z offers identical performance in a functionally equivalent package; versus DRV10970PWP, it trades higher current capability for integrated Hall bias and status outputs-making it optimal for cost-sensitive, space-constrained fan control where simplicity and reliability are prioritized.

Availability

MP6505DM-LF-Z is available at Aetrix Electronics and suitable for CPU fan control, server chassis cooling, and industrial embedded fan modules requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for MP6505DM-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 mixed-signal ICs for power management, motor control, and interface applications.

The MP6505 belongs to MPS's integrated motor driver product line, designed specifically for compact, reliable, and low-BOM-cost BLDC fan control in computing and communications infrastructure.

FAQ

What is the maximum continuous motor current supported by MP6505DM-LF-Z?

The MP6505DM-LF-Z supports 400mA continuous output current at room temperature with proper PCB thermal design. Peak current depends on Hall differential voltage (IN+–IN−) and internal gain of 9A/V, reaching up to 1.3A at ±50mV input. Derating is required above 25°C ambient due to thermal limits.

Does MP6505DM-LF-Z require an external Hall sensor?

Yes - the MP6505DM-LF-Z requires an external bipolar Hall-effect sensor connected between IN+, IN−, and HB. The IC provides the 1.2V bias (HB), differential amplification, and commutation logic, but does not integrate the magnetic sensing element.

How is locked-rotor protection implemented and can it be disabled?

Locked-rotor protection uses the CT pin capacitor charged by ICT1 (1.1–2.85μA). When Hall signal stops toggling, voltage rises to VCTH (3.6V), triggering shutdown and RD high-impedance state. It cannot be fully disabled but can be made non-functional by leaving CT unconnected or tying it to GND.

What is the purpose of the S-GND and P-GND pins, and how should they be routed?

S-GND (pin 14) is the signal ground for Hall inputs, reference circuits, and logic; P-GND (pins 1,16) carries high-current motor return paths. They must be separated on PCB and joined at a single point near the device's thermal pad to prevent noise coupling into sensitive analog sections.

Can MP6505DM-LF-Z drive motors without a Hall sensor?

No - the MP6505DM-LF-Z relies exclusively on Hall sensor feedback for commutation timing and current limiting. It lacks sensorless BEMF detection circuitry and will not operate with open or shorted Hall inputs.

What is the recommended capacitor value for the COSC pin to achieve 30kHz switching frequency?

A 100pF capacitor on the COSC pin yields a typical oscillator frequency of 30kHz, as specified in the datasheet. The relationship is approximately f_COSC ≈ 3×10⁶ / C_P (Hz), so values between 85pF–115pF maintain operation within the 26.4–35.6kHz specification range.

Is MP6505DM-LF-Z compatible with 3.3V logic-level PWM signals on the VTH pin?

Yes - the VTH pin accepts 0.2V–3V input for analog speed control, making it directly compatible with standard 3.3V microcontroller PWM outputs. No level-shifting is required, and internal circuitry interprets the average voltage for duty-cycle mapping.