Monolithic Power Systems Inc. MP9517GJS-Z

Overview

MP9517GJS-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), 3.3V–18V input range, and 2A overload current limit. It delivers closed-loop speed control via PWM input (2kHz–100kHz), provides rotational speed feedback on open-drain FG pin, and targets CPU/server fan applications requiring low audible noise and high reliability.

For engineers reviewing the MP9517GJS-Z datasheet, MP9517GJS-Z pinout, MP9517GJS-Z application, or MP9517GJS-Z equivalent, this page details its Hall-based commutation logic, soft-on/off timing (22.5°/45°), fixed 26kHz switching frequency, rotor deadlock detection (0.6s timeout), and thermal shutdown (150°C) - all critical for fan driver validation and BOM selection.

Technical Context

The MP9517GJS-Z implements Hall-sensor-triggered, single-phase BLDC commutation with automatic winding BEMF and current zero-crossing alignment in the same phase. Its internal half-bridge drives OUT1/OUT2 with soft-switching control, while the embedded Hall sensor (±1mT sensitivity) directly interfaces with rotor magnet polarity transitions to initiate commutation timing.

Control is fully integrated: PWM input sets target duty cycle (7.8%–100%), which linearly modulates output conduction; FG outputs Hall-edge pulses at motor speed; reverse voltage protection blocks -18V faults; and UVLO (3.25V rising) disables operation below safe supply levels.

Key Specifications

Pinout & Package

MP9517GJS-Z is packaged in TSOT23-6-SL - a 6-pin, surface-mount, lead-free, halogen-free package with 0.95mm pitch and exposed pad for thermal dissipation (θ_JA = 100°C/W).

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 A4964KJPTR-T, MP9517GJS-Z uniquely integrates Hall sensing, soft commutation timing, and reverse-voltage protection in a 6-pin TSOT23 package - reducing bill-of-materials, layout complexity, and qualification effort for cost-sensitive CPU/server fan designs.

Availability

MP9517GJS-Z is available at Aetrix Electronics and suitable for CPU fan control, server chassis cooling, and network switch thermal management requiring stable component supply, RoHS-compliant packaging, and long-lifecycle availability.

Supply support for MP9517GJS-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 over 20 years of expertise in DC/DC converters, motor drivers, and LED drivers.

The MP9517 belongs to MPS's integrated fan driver product line, designed specifically to replace discrete MOSFET+Hall+controller solutions in space-constrained, low-noise, high-reliability cooling applications.

FAQ

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

The MP9517GJS-Z requires a minimum input PWM duty cycle of 7.8% to initiate rotation. Below this threshold, the motor remains stationary. A 1.2% hysteresis prevents oscillation near the startup point, so rotation resumes only when duty exceeds 9% after a stall event.

Does MP9517GJS-Z require an external pull-up resistor on the FG pin?

Yes. The FG pin is an open-drain output and must be pulled up externally - typically with a 4.7kΩ to 10kΩ resistor to a 3.3V or 5V rail. Without this pull-up, FG cannot generate valid tachometer pulses for speed monitoring or closed-loop control.

How does rotor deadlock protection operate, and what happens after detection?

When no Hall signal edge is detected for 0.6 seconds, MP9517GJS-Z activates rotor deadlock protection by turning on both low-side MOSFETs for forced conduction. After a 3.6-second hold period, it automatically attempts restart. FG resumes output only after detecting three consecutive Hall edges post-recovery.

What is the purpose of the 2Ω resistor in series with the input capacitor in the typical application circuit?

The 2Ω resistor forms an RC snubber with the input capacitor to dampen ringing caused by energy exchange during soft-switching commutation. This suppresses high-frequency voltage spikes on VCC, improving EMC performance and preventing false UVLO or OVP triggering.

Can MP9517GJS-Z drive motors beyond CPU/server fan loads?

No. MP9517GJS-Z is optimized for single-phase BLDC fans with ≤2A peak current and ≤18V supply. Its 1.02Ω total R_DS(on), thermal limits (1.25W P_D), and Hall sensitivity (±1mT) are calibrated for small-form-factor axial fans - not for pumps, blowers, or industrial motors requiring higher torque or voltage.

Is MP9517GJS-Z pin-compatible with other MPS fan drivers like MP6532?

No. MP9517GJS-Z uses a 6-pin TSOT23-6-SL package with dedicated Hall-integrated functionality, while MP6532 uses an 8-pin SOIC package and lacks integrated Hall sensing. Pin functions, package dimensions, and control architecture differ fundamentally - no mechanical or electrical compatibility exists.