Monolithic Power Systems Inc. MP6509GF

Overview

MP6509GF from Monolithic Power Systems is a bipolar stepper motor driver IC with dual integrated N-channel full-bridge MOSFETs, delivering up to 1.2A per channel across a 2.7V–18V supply range. It supports external PWM and internal constant-off-time current control, features four selectable current attenuation modes (20%–100%), and includes OCP, UVLO, thermal shutdown, and open-drain fault flag - deployed in POS printers and battery-powered camera pan/tilt mechanisms.

For engineers reviewing the MP6509GF datasheet, MP6509GF pinout, MP6509GF application, or MP6509GF equivalent, key selection considerations include its TSSOP-20 EP thermally enhanced package, 250mΩ HS/LS R_DS(on), 1µA sleep current, 21–31µs constant off-time, and dual-bridge gate logic compatibility with microcontroller step/direction interfaces.

Technical Context

The MP6509GF implements two independent full-bridge drivers with synchronous rectification during slow-decay freewheeling, reducing conduction loss versus body-diode decay. Its internal charge pump enables high-side N-MOSFET drive without external bootstrap components.

Current regulation operates via either externally applied PWM on AIN1/AIN2/BIN1/BIN2 pins or internal constant-off-time control using external sense resistors (SENA/SENB) and programmable V_REF attenuation (ATT1/ATT2), supporting precise hold/run current scaling for torque optimization and thermal management.

Key Specifications

Pinout & Package

The MP6509GF is housed in a thermally enhanced 20-pin TSSOP-EP package (6.5mm × 6.4mm) with an exposed pad for PCB-level heat sinking - critical for sustaining 1.2A output under 18V input and ambient temperatures up to +85°C.

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 MP6509GF uniquely balances ultra-low sleep current (1µA), thermally efficient TSSOP-EP packaging, and four-step V_REF attenuation - making it optimal for portable, battery-sensitive stepper applications where hold-current optimization and compact layout are critical.

Availability

MP6509GF is available at Aetrix Electronics and suitable for POS printers, video security cameras, and digital still cameras requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for MP6509GF 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 MP6509GF belongs to MPS's integrated motor driver product line, engineered for compact, thermally constrained motion control applications requiring high integration, low quiescent power, and robust fault handling.

FAQ

What is the maximum continuous output current per bridge for MP6509GF?

The MP6509GF delivers up to 1.2A continuous output current per bridge under recommended operating conditions (TA ≤ +85°C, proper PCB thermal design). This rating assumes use of the exposed-pad TSSOP-20 EP package with ≥2 cm² of 2-oz copper connected to the thermal pad, and accounts for R_DS(on) derating above 25°C.

How does the ATT1/ATT2 pin configuration affect motor current control?

ATT1 and ATT2 set the V_REF attenuation ratio (100%/80%/50%/20%), directly scaling the current limit threshold applied to the external sense resistor. For example, with ATT1=L/ATT2=H (50% mode), a 0.2Ω sense resistor yields 100mA limit instead of 200mA - enabling reduced holding current without changing hardware or firmware.

Can MP6509GF drive two independent DC motors instead of a stepper motor?

Yes - the dual full-bridge architecture supports independent DC motor control. Each bridge (A and B) can be driven separately using AIN1/AIN2 and BIN1/BIN2 inputs. Direction and speed are controlled via standard H-bridge logic, and current limiting remains active per bridge using SENA/SENB sense resistors.

What is the purpose of the BST pin and required external component?

The BST pin connects to an external 10nF–100nF ceramic capacitor tied to VIN. This forms a charge pump that generates a voltage higher than VIN to fully enhance the high-side N-channel MOSFETs - eliminating the need for external bootstrap diodes or capacitors typically required in high-side gate drive circuits.

Does MP6509GF support microstepping or only full/half-step operation?

The MP6509GF natively supports full-step and half-step excitation via sequential AIN/BIN logic control. It does not include built-in microstepping circuitry (e.g., sine/cosine DAC or细分 logic). Microstepping requires external PWM generation with intermediate duty cycles - achievable using MCU timers but not handled autonomously by the IC.

How does the FAULT pin behave during over-current and thermal events?

The FAULT pin is an open-drain output that pulls low during over-current protection (OCP) or thermal shutdown (OTP). It remains low for ≥2ms after fault initiation, then auto-recovers if the fault condition clears. Only the affected bridge is disabled - the other bridge continues normal operation unless also faulted.

Is there a minimum blanking time for current sensing, and why is it needed?

Yes - the MP6509GF applies a 2–3µs internal blanking time (T_BLANK) after each bridge switching edge. This prevents false OCP triggering caused by transient current spikes from MOSFET body diode reverse recovery or PCB parasitics - ensuring accurate current regulation during steady-state operation.