Pololu High-Power Stepper Motor Driver 36v4 (DRV8711 + MOSFETs) — 8–50V, up to 4A/phase

For big steppers, higher voltages, and serious current: the Pololu High-Power Stepper Motor Driver 36v4 pairs TI’s DRV8711 gate-driver IC with external MOSFET H-bridges to drive one bipolar stepper motor from 8V to 50V. It can deliver up to 4A continuous per phase without a heatsink or forced airflow (and up to around 6A max with sufficient cooling), while offering deep configurability via SPI— including microstepping (down to 1/256), current limiting, decay modes, and stall-related features.

High power range: 8–50V motor supply with high current capability (thermally dependent).
Nine step modes: full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256 microsteps.
Control options: configure through SPI; stepping can be done via optional STEP/DIR pins or through SPI alone.
Stall & feedback: optional STALL output + BEMF analog output for back-EMF based algorithms.
Logic-friendly: inputs work with 1.8V/3.3V/5V systems; outputs are open-drain pulled up to IOREF.
Protection: under-voltage lockout, over-current/short protection, and reverse-voltage protection (up to 40V).

Critical setup notes (prevents most “dead driver” issues):

You MUST configure it after every power-up: the board needs SPI configuration + enable before use, even if you plan to drive it with STEP/DIR.
Set current limit first: it defaults to the maximum current limit on start-up, which is more than the board can safely deliver—set an appropriate current limit via SPI before enabling outputs.
Never plug/unplug motors while powered: connecting/disconnecting a stepper motor while powered can destroy the driver.
High VIN + high current = more noise: at high voltages (especially >30V) and high current limits, SPI can be affected by electrical noise—use careful wiring and verify writes.

Why/Benefits

High voltage + current, compact board

Run larger steppers at higher supply voltages while limiting coil current for faster step rates.
Up to 4A/phase continuous without extra cooling in typical conditions; add cooling for higher peaks.
Board footprint around 33.0 × 30.5 mm (dimension drawing).

“Tunable motion” via SPI

Fine microstepping + configurable decay/blanking for smoother motion profiles.
Optional STALL output and BEMF analog output for advanced sensing/control.
Also supports an alternate mode to control two brushed DC motors (PWM inputs) instead of a stepper.

Technical specifications

Product	Pololu High-Power Stepper Motor Driver 36v4
Driver IC	Texas Instruments DRV8711 (with external MOSFET H-bridges)
Motor type	1× bipolar stepper motor (alternate mode: 2× brushed DC motors)
Motor supply (VIN)	8–50V (reverse-voltage protected up to 40V)
Continuous current	Up to 4A per phase (no heatsink/forced airflow, typical; thermally dependent)
Max current	Up to ~6A per phase with sufficient cooling
Microstepping	Full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256
Control / config	SPI (required after power-up); optional STEP/DIR pins
Logic voltage	1.5–5.5V (inputs compatible with 1.8V/3.3V/5V)
IOREF behavior	Open-drain outputs pulled up to externally supplied IOREF
V5 output	Internal 5V regulator output (up to 10mA; disabled in sleep)
Board size	~33.0 × 30.5 mm (dimension drawing)

Pinout & power notes

VIN / GND: motor supply input (8–50V). Reverse protection applies up to 40V.
VM: reverse-protected motor supply node after the protection MOSFET—can also be used for adding extra bypass capacitance with adjacent GND.
AOUT1/AOUT2, BOUT1/BOUT2: connect to the two stepper coil pairs (phase A and phase B).
IOREF: set this to your controller logic voltage (e.g., 3.3V). Outputs pull up to IOREF. V5 (OUT): optional 5V reference from internal regulator (up to 10mA) mainly for pull-ups / tying inputs high; not for powering external loads.
SPI: SDATI (MOSI), SDATO (MISO, open-drain), SCLK, SCS. SPI is required for configuration after each power-up.
SLEEP / RESET / FAULT: SLEEP must be driven high to run; FAULT is open-drain, pulled up to IOREF.
STEP / DIR: optional step interface (still requires SPI setup first).

FAQ

Can I use this like a normal STEP/DIR driver?

Yes, STEP/DIR pins are supported, but you still must configure and enable the DRV8711 via SPI after every power-up.
Do I really need to set the current limit first?

Yes. It defaults to the maximum current limit at start-up—set a safe current limit via SPI before enabling outputs to avoid damage.
Is it 3.3V compatible?

Yes. Inputs support 1.5–5.5V, and open-drain outputs pull up to IOREF (set IOREF to 3.3V for 3.3V systems).