Monolithic Power Systems Inc. MP6509GF-Z

Overview

MP6509GF-Z 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 four selectable current attenuation modes (20–100%), internal charge pump for high-side drive, 250mΩ typical R_DS(on) per FET, and fault indication via open-drain FAULT pin. Used in compact motion control systems such as POS printers and battery-powered camera gimbals.

For engineers reviewing the MP6509GF-Z datasheet, MP6509GF-Z pinout, MP6509GF-Z application, or MP6509GF-Z equivalent, key selection criteria include its integrated full-bridge topology, 1.2A continuous output capability, 2.7V–18V input range, thermal shutdown at 165°C, and support for both external PWM and internal constant-off-time current regulation.

Technical Context

The MP6509GF-Z implements two independent full-bridge drivers with synchronous rectification during slow-decay freewheeling, reducing conduction loss versus body-diode decay. Its internal constant-off-time PWM controller uses an external sense resistor and configurable V_REF attenuation (via ATT1/ATT2) to set winding current limits from 15mV to 233mV reference thresholds.

Protection architecture includes independent high-side and low-side over-current detection (IOCP1 = 2.2–4.6A, IOCP2 = 1.8–3A), 2.5µs blanking time to suppress switching spikes, UVLO with 2.5V rising threshold and 30–120mV hysteresis, and thermal shutdown with 15°C hysteresis. Fault status is reported on an open-drain FAULT pin active-low for OCP or OTP events.

Key Specifications

Pinout & Package

The MP6509GF-Z is housed in a thermally enhanced 20-pin TSSOP-EP package (6.5mm × 6.4mm) with exposed thermal pad on the underside for PCB-level heat transfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TB6600HG and DRV8811PWPR, the MP6509GF-Z uniquely balances compact TSSOP-20 EP packaging, 1µA sleep current, and hardware-configurable current attenuation - making it optimal for space-constrained, battery-sensitive motion systems requiring reliable fault visibility.

Availability

MP6509GF-Z is available at Aetrix Electronics and suitable for POS printers, video security cameras, and digital still cameras requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MP6509GF-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 analog and power ICs, with design centers across Asia and North America.

The MP6509 belongs to MPS's motor driver product line, engineered specifically for compact, efficient bipolar stepper control in consumer and industrial edge devices where integration, thermal performance, and low-power operation are critical.

FAQ

What is the maximum motor supply voltage supported by the MP6509GF-Z?

The MP6509GF-Z supports a continuous input voltage range of 2.7V to 18V on the VIN pin, with absolute maximum rating of 20V. Operation above 18V risks exceeding safe junction temperature or violating SOA limits, even if within absolute max ratings - sustained use must remain within the recommended 2.7V–18V operating range.

How does the ATT1/ATT2 configuration affect motor current accuracy?

ATT1 and ATT2 set the V_REF attenuation ratio (20%, 50%, 80%, or 100%), directly scaling the current limit equation I_LIMIT = (V_REF × attenuation) / R_SENSE. At 20% attenuation, the same R_SENSE yields 5× lower current than at 100%, enabling precise hold/run current ratios without changing hardware.

Can the MP6509GF-Z drive unipolar stepper motors?

No - the MP6509GF-Z is designed exclusively for bipolar stepper motors with center-tapped or dual-winding configurations. Its dual full-bridge topology requires four-terminal connection per winding (AOUT1/AOUT2, BOUT1/BOUT2) and cannot interface with unipolar 5- or 6-wire steppers that rely on common taps and transistor arrays.

What is the purpose of the BST pin and required capacitor value?

The BST pin supplies the bootstrap capacitor for the high-side gate driver. A 10nF to 100nF ceramic capacitor must be placed between BST and VIN to generate a voltage >VIN for turning on the N-channel high-side MOSFETs. Values outside this range risk insufficient gate drive or excessive ringing during switching transitions.

Does the FAULT pin require an external pull-up resistor?

Yes - the FAULT pin is open-drain and requires an external pull-up resistor (typically 4.7kΩ to VDD or system logic rail) to assert a valid high level during normal operation. Without it, the pin remains floating and cannot reliably signal fault conditions to a microcontroller GPIO or interrupt input.

How does the internal blanking time prevent false over-current trips?

The 2.5µs blanking time disables the current sense comparator immediately after bridge switching, masking transient current spikes caused by body diode reverse recovery or parasitic inductance. This ensures only sustained over-current events - not nanosecond-scale artifacts - trigger protection, improving noise immunity in electrically noisy environments.

Is thermal pad soldering required for reliable operation?

Yes - the exposed thermal pad on the TSSOP-20 EP package must be soldered to a dedicated PCB copper pour connected to GND. Omitting this compromises θ_JA performance, increasing junction temperature by >30°C at 1.2A and risking premature thermal shutdown or reduced lifetime.