Monolithic Power Systems Inc. MP6601GU-Z

Overview

MP6601GU-Z from Monolithic Power Systems is a 35V, 2.5A bipolar stepper motor driver IC with integrated dual full-bridge MOSFETs, internal current sensing (no external sense resistors), and programmable constant-off-time PWM control. It supports full-, half-, and quarter-step modes via PHASE/I0/I1 logic interface and delivers up to 2.5A per bridge under thermal limits. Used in compact motion control systems such as industrial printers and automated lab equipment.

For engineers reviewing the MP6601GU-Z datasheet, MP6601GU-Z pinout, MP6601GU-Z application, or MP6601GU-Z equivalent, key selection criteria include its 4.5–35V input range, QFN-24 (5mm×5mm) thermally enhanced package, internal 170mΩ/150mΩ HS/LS R_DS(on), fault-indicating open-drain nFAULT output, and automatic decay mode for precise current regulation in bipolar stepper drives.

Technical Context

The MP6601GU-Z implements two independent N-channel H-bridges with integrated gate drivers, charge pump (VCP/CP1/CP2), and internal current-sense amplifiers. Its constant-off-time PWM controller uses an external ROSC resistor to set t_OFF (20–26 µs typical) and an ISET resistor to define peak current (e.g., 1.0A at 71kΩ).

It features autonomous decay mode switching-initiating slow decay by default and transitioning to fast decay only when winding current remains above trip threshold after fixed off-time-enabling stable microstepping without external decay configuration. Protection includes OCP (6A trip), OVP (37.5V threshold), UVLO (4.5V rising), and thermal shutdown (165°C).

Key Specifications

Pinout & Package

MP6601GU-Z is housed in a thermally enhanced QFN-24 (5mm × 5mm) package with exposed pad for PCB heat sinking. Pin numbering follows JEDEC MO-220 standard; Pin 1 is marked by top-side index area.

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, MP6601GU-Z offers superior integration (no sense resistors, single-supply logic), wider 35V OVP tolerance, and tighter current regulation accuracy-making it optimal for industrial motion systems requiring reliability and board-area efficiency.

Availability

MP6601GU-Z is available at Aetrix Electronics and suitable for industrial printers, automated lab equipment, 3D printer motion control, and CNC engraving systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP6601GU-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 in the US, China, and Taiwan.

The MP6601 belongs to MPS's stepper motor driver product line, engineered for compact, thermally efficient bipolar stepper control in space-constrained industrial and automation equipment.

FAQ

What is the maximum continuous motor current supported by MP6601GU-Z?

The MP6601GU-Z supports up to 2.5A per bridge continuously under proper thermal conditions: using the QFN-24 package on a 4-layer PCB with ≥6 thermal vias to a solid ground plane, ambient temperature ≤60°C, and VIN ≤24V. At 35V or elevated ambient, derating applies per θ_JA = 36°C/W and TJ(max) = 150°C.

Does MP6601GU-Z require external current-sense resistors?

No. The MP6601GU-Z integrates precision current-sense circuitry and eliminates external sense resistors entirely. Motor current is regulated using internal MOSFET R_DS(on) sensing, reducing BOM cost, PCB area, and power loss associated with shunt-based sensing.

How does the automatic decay mode function without configuration?

The MP6601GU-Z monitors winding current decay after each fixed off-time. If current remains above the trip threshold, it automatically switches to fast decay; if current falls below threshold, it defaults to slow decay. This closed-loop behavior adapts to motor inductance and supply voltage without user intervention or register writes.

Can MP6601GU-Z drive DC brush motors?

Yes-it can drive two independent DC brush motors using its dual H-bridges. However, both bridges share the same ISET-defined current limit, so stall current must be identical for both motors. Short-brake functionality is not supported; coasting is achieved by setting both outputs to high-impedance via PHASE control.

What is the purpose of the ROSC pin, and how is it configured?

ROSC sets the constant off-time (t_OFF) of the PWM current regulator via an external resistor to ground. A 200kΩ resistor yields ~23 µs t_OFF. Shorter t_OFF enables higher step rates but increases current ripple; longer t_OFF improves regulation at low speeds and reduces audible noise.

Is MP6601GU-Z compatible with 3.3V microcontrollers?

Yes. All logic inputs (APHASE, BPHASE, AI0, AI1, nSLEEP) are 3.3V- and 5V-compatible with VIH(min) = 2.1V and VIL(max) = 0.8V. No level-shifting circuitry is required when interfacing with modern ARM Cortex-M or ESP32 GPIOs.

How is thermal performance affected by the QFN-24 package?

The QFN-24 (5mm×5mm) package features an exposed thermal pad that must be soldered to a PCB ground plane with ≥6 thermal vias. With this layout, θ_JA = 36°C/W enables 2.5A operation at TA = 60°C. Without proper thermal design, power dissipation is limited to ~1.5W before thermal shutdown activates at 165°C.