Monolithic Power Systems Inc. MP6508GF-P

Overview

MP6508GF-P from Monolithic Power Systems is a bipolar stepper motor driver IC integrating dual N-channel full-bridge MOSFETs, operating from 2.7V to 18V supply and delivering up to 1.2A per channel. It features integrated OCP, UVLO, thermal shutdown, fault flag output, and low quiescent current (1.6mA), targeting compact motion control in battery-powered and industrial positioning systems.

For engineers reviewing the MP6508GF-P datasheet, MP6508GF-P pinout, MP6508GF-P application, or MP6508GF-P equivalent, key selection criteria include its 250mΩ high-side/low-side R_DS(on), internal charge pump for high-side gate drive, 1µA sleep current, constant off-time PWM current regulation, and TSSOP-16 EP thermally enhanced package with exposed pad.

Technical Context

The MP6508GF-P implements two independent full-bridge drivers with synchronous rectification during slow-decay current decay, reducing conduction loss versus body-diode freewheeling. Its internal constant off-time (21–31µs) PWM controller regulates winding current via external sense resistors (R_SENSE) and a 204mV typical V_REF threshold.

Protection logic includes independent per-bridge over-current detection (2.2–4.6A high-side, 1.8–3A low-side trip), 1.1µs deglitch time, and thermal shutdown at 165°C with 15°C hysteresis. The nSLEEP pin enables 1µA standby mode with ~0.75ms wake-up latency and internal regulator/gate driver shutdown.

Key Specifications

Pinout & Package

TSSOP-16 EP package (5.0mm × 6.4mm) with exposed thermal pad soldered to PCB ground plane for enhanced thermal dissipation (θ_JA = 45°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TB6600HG and DRV8825, the MP6508GF-P offers superior integration (built-in charge pump, lower sleep current, smaller TSSOP-16 EP footprint) at the expense of microstepping capability and peak current - making it optimal for cost-sensitive, space-limited full/half-step motion control.

Availability

MP6508GF-P is available at Aetrix Electronics and suitable for POS printers, video security cameras, digital still cameras, and battery-powered toys requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP6508GF-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.

The MP6508 belongs to MPS's motor driver product line, engineered for compact, efficient bipolar stepper control in portable and embedded motion systems - emphasizing thermal robustness, integrated protection, and minimal external component count.

FAQ

What is the maximum allowable motor supply voltage for MP6508GF-P?

The absolute maximum VIN rating is 20V, but the recommended operating range is 2.7V to 18V. Operation above 18V risks exceeding junction temperature limits under load and violates the specified operating conditions; sustained use beyond 18V may trigger UVLO or cause premature thermal shutdown.

How does the internal PWM current control determine motor winding current?

The MP6508GF-P uses a constant off-time architecture: it turns on a diagonal MOSFET pair until the voltage across the external sense resistor reaches 204mV (typical V_REF), then disables the high-side switch for a fixed 26µs off-time. Current is calculated as I_LIMIT = V_REF/R_SENSE, enabling precise, resistor-programmable current regulation without external controllers.

Can MP6508GF-P drive two independent DC motors instead of a stepper motor?

Yes - the dual full-bridge topology supports independent bidirectional control of two brushed DC motors. Each bridge (A and B) operates separately: AIN1/AIN2 control motor A, BIN1/BIN2 control motor B. This enables applications like robotic differential drive or dual-axis fan control with shared power rail and fault reporting.

What is the purpose of the BST pin and what capacitor value is recommended?

The BST pin supplies the gate drive voltage for the high-side N-MOSFETs via an external bootstrap capacitor. A 10nF to 100nF ceramic capacitor (X7R or C0G) must connect between BST and VIN. Typical design uses 22nF or 47nF to ensure sufficient charge transfer during high-duty-cycle operation while minimizing voltage droop.

Does the FAULT pin indicate faults for both bridges simultaneously?

No - the FAULT pin is a wired-OR output that goes low if *either* bridge triggers over-current protection or thermal shutdown. It does not distinguish which bridge faulted. To isolate the fault source, monitor individual winding currents and temperatures externally, or implement software-based sequence validation to correlate timing with observed fault events.

Is the exposed thermal pad on the TSSOP-16 EP package required to be connected to ground?

Yes - the exposed pad must be soldered to a PCB copper pour connected to GND. This pad provides the primary thermal path (accounting for ~60% of total θ_JA) and also serves as the electrical ground reference for internal circuitry. Leaving it unconnected degrades thermal performance by >30°C and may cause instability or premature thermal shutdown.

What happens to motor outputs during nSLEEP assertion?

When nSLEEP is driven low, both full-bridges enter high-impedance state (all MOSFETs off), the internal LDO and charge pump shut down, and quiescent current drops to 1µA. Motor windings are electrically disconnected, eliminating holding torque and back-EMF coupling - critical for battery-powered systems needing zero-load standby.