Monolithic Power Systems Inc. MP6501AGF-Z

Overview

MP6501AGF-Z from Monolithic Power Systems is a bipolar stepper motor driver IC with integrated 2.5A dual full-bridge MOSFETs, microstepping translator, and 3.3V reference regulator. It operates from 8V to 35V input, supports full/half/quarter/eighth-step modes, features 220mΩ HS/LS R_ON, and delivers precise current control via external sense resistors - used in precision motion control for industrial printers and automated lab equipment.

For engineers reviewing the MP6501AGF-Z datasheet, MP6501AGF-Z pinout, MP6501AGF-Z application, or MP6501AGF-Z equivalent, this page provides verified functional context, validated pin roles, confirmed thermal and protection behavior, and real-world microstepping timing constraints - all critical for motor control layout, current loop design, and fault-handling integration.

Technical Context

The MP6501AGF-Z implements a constant off-time PWM current regulation architecture with programmable blanking time (2µs) and crossover dead time (400ns), enabling stable current control across 32 microsteps per electrical cycle. Its internal charge pump generates gate drive voltage for high-side N-MOSFETs using CPA/CPB/VCP pins and external 100nF + 1µF capacitors.

It integrates dual independent current-sense comparators tied to SENA/SENB inputs, with trip thresholds referenced to VREF (600–700mV typical), and supports mixed decay mode controlled by MDS voltage (0–2.5V for adjustable fast-decay ratio; >2.8V for automatic decay). Fault reporting is handled via open-drain nFAULT, asserting low on OCP, OTP, or OVP events.

Key Specifications

Pinout & Package

TSSOP-28 EP (9.7mm × 6.4mm) with exposed thermal pad soldered to PCB ground plane for enhanced thermal dissipation (θ_JA = 32°C/W, θ_JC = 6°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, MP6501AGF-Z uniquely combines single-supply operation (no external logic rail), integrated 3.3V reference, open-drain nHOME for hardware homing, and analog MDS-controlled mixed decay - making it optimal for compact, self-contained motion modules requiring robust diagnostics and fine-grained current control.

Availability

MP6501AGF-Z is available at Aetrix Electronics and suitable for industrial printers, automated lab instruments, CNC engraving systems, and 3D printer extruder control requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP6501AGF-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 core expertise in DC/DC conversion, motor control, and integrated power stages.

The MP6501A belongs to MPS's stepper motor driver product line, designed specifically for compact, high-efficiency bipolar stepper control in industrial automation and precision instrumentation - emphasizing integrated FETs, microstepping intelligence, and robust protection.

FAQ

What is the minimum STEP pulse width required for reliable operation?

The MP6501AGF-Z requires a minimum STEP high/low pulse width of 1µs, with 200ns setup and hold time relative to the rising edge. This timing constraint ensures proper sampling of DIR, MSx, and MDS states before translator advancement - critical for avoiding missed steps or erratic microstep sequencing in high-speed applications.

How does the MDS pin affect current decay behavior?

The MDS pin sets decay mode: 0V selects slow decay for maximum torque retention; 0–2.5V enables adjustable mixed decay (fast-decay % ≈ 4.0 × V_MDS × t_OFF); >2.8V activates automatic decay that switches between slow and mixed based on current direction change. This directly impacts torque ripple, mid-band resonance, and motor heating.

Can the 3P3VOUT pin power external circuitry beyond the IC's own logic?

3P3VOUT delivers up to 1mA at 3.3V ±3.5%, intended primarily for internal logic and VREF biasing. While it may power small external logic (e.g., level shifters or GPIO pull-ups), it is not rated for sustained loads >1mA - external regulation is recommended for higher-current peripherals to avoid VREF instability and translator errors.

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

Asserting nSLEEP disables the charge pump, 3P3VOUT regulator, H-bridges, and all internal logic - reducing quiescent current to 1µA. After de-assertion, ~1ms is required for internal circuits (especially charge pump and reference) to stabilize before issuing the first STEP command; otherwise, initial steps may stall or misfire.

Is over-current protection dependent on the external sense resistor value?

No - OCP is implemented independently of SENA/SENB and VREF, using dedicated high-side and low-side current monitors with fixed 3.5–10A trip thresholds. It protects against shorts to GND, VIN, or cross-winding faults regardless of sense resistor selection - ensuring fail-safe shutdown even if current regulation is misconfigured.

How is the home position determined and signaled?

The nHOME pin asserts low when the internal translator reaches step #1 (45° electrical angle), corresponding to maximum positive current in Phase A and zero current in Phase B. This occurs automatically after nRSET de-assertion or power-up reset - providing hardware-level homing without encoder feedback or software polling.

What thermal performance can be expected in TSSOP-28 EP with standard PCB layout?

With a 4-layer PCB per JESD51-7, the MP6501AGF-Z achieves θ_JA = 32°C/W. At 2.5A per bridge and 24V input, power dissipation is ~2.8W - resulting in ~90°C junction rise above ambient. Full derating begins above 85°C ambient; use of the exposed pad (soldered to solid GND plane) is mandatory for rated performance.