Monolithic Power Systems Inc. MP9517GJL-Z

Overview

MP9517GJL-Z from Monolithic Power Systems is a single-phase brushless DC motor driver IC with integrated Hall-effect sensor, power MOSFETs (HS+LS R_DS(on) = 1.02Ω), and reverse voltage protection. It operates from 3.3V to 18V, supports 2kHz–100kHz PWM speed control, delivers up to 2A output current limit, and provides open-drain FG speed feedback - designed for CPU/server fan drive applications requiring low audible noise and automatic rotor-lock recovery.

For engineers reviewing the MP9517GJL-Z datasheet, MP9517GJL-Z pinout, MP9517GJL-Z application, or MP9517GJL-Z equivalent, key selection criteria include integrated Hall sensing, soft-on/off commutation timing (22.5°/45°), fixed 26kHz switching frequency, thermal shutdown at 150°C, and TSOT23-6-L package compatibility with space-constrained fan modules.

Technical Context

The MP9517GJL-Z implements closed-loop BLDC commutation using an on-die Hall sensor to detect rotor position and synchronize winding BEMF with current zero-crossing in the same phase. Its internal half-bridge drives OUT1 and OUT2 with soft-switching control logic that modulates duty cycle based on external PWM input while maintaining constant 26kHz output switching.

Protection architecture includes input OVP (19V trip), UVLO (3.25V rising threshold), rotor deadlock detection (0.6s timeout), thermal shutdown (150°C with 25°C hysteresis), and reverse polarity blocking - all with automatic recovery. The FG pin outputs a Hall-edge-triggered open-drain signal proportional to rotational speed.

Key Specifications

Pinout & Package

MP9517GJL-Z is housed in a TSOT23-6-L package - a 2.9mm × 1.6mm × 0.9mm leaded surface-mount outline with gull-wing leads, optimized for high-density PCB layouts in fan modules and embedded cooling systems.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6532GJ-Z and TB6612FNG, MP9517GJL-Z delivers lowest system-level component count and fastest time-to-operation for single-fan applications, trading off flexibility for integration density and autonomous protection behavior.

Availability

MP9517GJL-Z is available at Aetrix Electronics and suitable for CPU fan control in servers, embedded cooling for network switches, and industrial PC heat management requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP9517GJL-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 power management ICs, with design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MP9517 belongs to MPS's integrated motor driver product line, engineered specifically for compact, intelligent cooling solutions in computing and communications infrastructure where size, noise, and reliability are critical.

FAQ

What is the minimum PWM duty cycle required to start motor rotation?

The MP9517GJL-Z requires ≥9% PWM duty cycle to initiate rotation, with 1.2% hysteresis to prevent unstable start-stop cycling. Below 7.8%, the motor remains stationary regardless of applied voltage. This threshold is fixed and not adjustable via external components.

Does MP9517GJL-Z support 5V-only operation?

Yes - the 3.3V to 18V input range fully covers 5V nominal supplies. At 5V, the device delivers up to 1.7A continuous output current (per Electrical Characteristics table), sufficient for most 40–60mm axial fans, with UVLO releasing at 3.25V to ensure stable startup.

How is FG signal frequency related to motor speed?

FG outputs one pulse per Hall sensor edge transition. For a two-pole motor, this equals one pulse per electrical revolution - so FG frequency = motor RPM ÷ 60. The open-drain output requires an external pull-up resistor (typically 4.7kΩ to 5V or 3.3V) to generate a valid logic signal.

Can MP9517GJL-Z drive motors with non-standard pole counts?

It is optimized for two-pole BLDC motors common in fans. While it may operate with other configurations, Hall sensor sensitivity (±1mT) and commutation timing assume standard magnet geometry. Performance with >2-pole motors is not characterized and may require validation.

What thermal derating applies at 85°C ambient?

At T_A = 85°C, maximum allowable power dissipation drops to 0.625W (calculated via P_D(MAX) = (150°C − 85°C) ÷ 100°C/W). This limits continuous output current to ~1.3A at 12V, requiring careful thermal pad layout and optional copper pour to maintain safe junction temperature.

Is TSOT23-6-L pinout identical to TSOT23-6-SL?

Yes - both packages share identical pin numbering and function mapping (GND/VCC/FG/PWM/OUT2/OUT1). The difference lies solely in mold compound profile and land pattern dimensions; PCB footprints are not interchangeable without layout revision.

Does reverse voltage protection activate below 0V or only at negative supply?

Reverse protection activates when VCC is driven below GND - i.e., true polarity reversal. It does not respond to transient undershoot or ground bounce. The IC draws only 1mA reverse current at –18V, preventing latch-up or permanent damage.