Monolithic Power Systems Inc. MP6518GF-P

Overview

MP6518GF-P from Monolithic Power Systems is a bipolar stepper motor driver IC with integrated dual full-bridge N-channel MOSFETs, 35V max supply voltage, 1.5A continuous output current per phase, and built-in microstepping translator supporting full/half/quarter/eighth-step modes. It delivers precise current control via external sense resistors and operates without a separate logic supply using its internal 3.3V regulator - deployed in security camera pan-tilt mechanisms requiring smooth low-vibration motion.

For engineers reviewing the MP6518GF-P datasheet, MP6518GF-P pinout, MP6518GF-P application, or MP6518GF-P equivalent, key selection considerations include its TSSOP-28-EP package thermal performance, adjustable mixed-decay ratio for torque ripple suppression, open-drain nFAULT/nHOME status outputs, and compatibility with 3.3V/5V logic interfaces in embedded motion control systems.

Technical Context

The MP6518GF-P implements a constant off-time PWM current regulation architecture with programmable blanking time (2 µs) and crossover dead time (400 ns), enabling stable current control across varying motor inductance and supply voltage (8–35V). Its translator generates precise sinusoidal current waveforms synchronized to STEP/DIR inputs and MS1–MS3 mode select pins.

Internal protection includes independent over-current detection (2.5–5.5A trip threshold), input over-voltage lockout (36–40V), UVLO (6.5–7.7V), and thermal shutdown (165°C), all reported via open-drain nFAULT. The charge pump (525 kHz) drives high-side gates using CPA/CPB/VCP pins and supports operation up to 1.5A per bridge with 300 mΩ typical R_DS(on) at 25°C.

Key Specifications

Pinout & Package

TSSOP-28-EP (9.7 mm × 6.4 mm) with exposed thermal pad - requires solder paste stencil design for optimal thermal transfer to PCB ground plane; JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stepper motor driver applications.

Compared with TB6600HG and DRV8825, the MP6518GF-P uniquely integrates a 3.3V regulator, charge pump, and nHOME output in a thermally optimized TSSOP-28-EP package - reducing external components by 4 and enabling single-rail 24V designs with production-grade diagnostics.

Availability

MP6518GF-P is available at Aetrix Electronics and suitable for security camera pan-tilt mechanisms, industrial textile machine axis control, and medical lab automation systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MP6518GF-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global distribution since 1997.

The MP6518 belongs to MPS's integrated motor driver product line, engineered specifically for compact, thermally constrained embedded motion systems requiring microstepping precision, robust protection, and minimal external components.

FAQ

What is the maximum allowable motor supply voltage for MP6518GF-P?

The absolute maximum VIN rating is 40V, but the recommended operating range is 8V to 35V. Operation above 35V risks triggering the input over-voltage protection (VOVP threshold 36–40V), which disables outputs and asserts nFAULT. Sustained operation near 40V may accelerate package degradation due to increased power dissipation in the 300 mΩ MOSFETs.

How does the MP6518GF-P achieve microstepping without an external clock?

The MP6518GF-P uses an internal translator that sequences motor phases based solely on STEP/DIR inputs and MS1–MS3 mode settings - no external clock or microcontroller firmware is needed. The translator generates precise current amplitude steps (e.g., 32 levels in eighth-step mode) via internal DACs referenced to VREF, synchronized to each STEP rising edge with 200 ns setup/hold timing.

Can the 3.3V regulator (3P3VOUT) power external circuitry beyond the MP6518GF-P itself?

Yes, the 3P3VOUT pin delivers up to 1 mA with ±3% regulation (3.2–3.45V at 1 mA load), sufficient to power small logic buffers, Hall-effect sensors, or microcontroller I/O peripherals. It must be decoupled with a 0.47 µF ceramic capacitor to GND; exceeding 1 mA load risks dropout or instability, especially at elevated temperatures.

What happens during nSLEEP assertion, and how long does wake-up take?

Asserting nSLEEP low disables the charge pump, 3.3V regulator, gate drivers, and all logic - reducing quiescent current to 5 µA. Upon release, internal circuits require ~1 ms to stabilize before accepting STEP commands; issuing STEP too early may cause missed steps or erratic behavior due to incomplete VCP ramp-up and VREF settling.

Is the MP6518GF-P compatible with 5V logic interfaces?

Yes, all digital inputs (STEP, DIR, MS1–MS3, nENBL, nSLEEP, nRSET) accept 3.3V or 5V logic levels: VIH is 2.0V min and VIL is 0.6V max, with ±25 µA input current at 5V. No level-shifting is required when interfacing with standard 5V microcontrollers or CPLDs, simplifying system integration.

How is over-current protection triggered, and does it depend on the sense resistor value?

The MP6518GF-P features two independent OCP circuits: one for PWM current regulation (using SENA/SENB and VREF) and a second dedicated high-threshold detector (2.5–5.5A) that monitors MOSFET conduction directly. The latter is independent of R_SENSE and VREF - ensuring reliable short-circuit protection even if current sensing is misconfigured or disabled.

What thermal design guidance applies to the TSSOP-28-EP package?

The TSSOP-28-EP has θ_JA = 32°C/W on a 4-layer PCB (JESD51-7). To sustain 1.5A continuous per phase at 24V, the exposed thermal pad must be soldered to a ≥200 mm² internal GND plane with ≥4 thermal vias (0.3 mm diameter). Without this, junction temperature may exceed 125°C derating limits, triggering thermal shutdown.