DRV8825 — Stepper Motor Driver Module

Overview

The DRV8825 is a complete microstepping bipolar stepper motor driver IC manufactured by Texas Instruments, commonly populated on Pololu-form-factor ("StepStick") breakout carrier modules.

Serving as a higher-voltage and higher-current drop-in alternative to the A4988 driver, the DRV8825 supports motor supply voltages up to 45 V, delivers up to 1.5 A continuous current per phase without forced air cooling (and up to 2.2 A with heatsinking and airflow), and offers microstepping resolution down to 1/32-step. It features adjustable current limiting via an onboard potentiometer, built-in indexer logic for simple STEP/DIR control, and internal protection against overcurrent, short circuits, thermal shutdown, and undervoltage lockout.

Quick reference


Motor supply voltage (`VMOT`)	8.2 V to 45.0 V DC
Logic supply voltage (`VVR`)	2.5 V to 5.25 V DC (internal 3.3V regulator)
Continuous current per phase	1.5 A (2.2 A max with heatsink/fan)
Microstep resolutions	Full, 1/2, 1/4, 1/8, 1/16, 1/32 step
Control interface	STEP / DIR pins (simple step and direction pulse)
MOSFET $R_{DS(on)}$	$300\text{ m}\Omega$ typical (high side + low side)
Form factor	16-pin 0.1" DIP carrier module (Pololu pinout)

Pinout

The module features two 8-pin 0.1" headers matching standard StepStick / RAMPS sockets:

Pin	Name	Type	Description
1	`ENABLE`	Digital Input	Active-Low driver enable. High = outputs disabled.
2	`M0`	Digital Input	Microstep resolution selector pin 0
3	`M1`	Digital Input	Microstep resolution selector pin 1
4	`M2`	Digital Input	Microstep resolution selector pin 2
5	`RESET`	Digital Input	Active-Low device reset (must be tied High for normal operation)
6	`SLEEP`	Digital Input	Active-Low sleep mode input (must be tied High for normal operation)
7	`STEP`	Digital Input	Step pulse input. Rising edge advances motor one step/microstep.
8	`DIR`	Digital Input	Direction input. Logic High = clockwise, Low = counter-clockwise.
9	`GND`	Power	Logic & Ground reference (0 V)
10	`FAULT`	Digital Output	Active-Low open-drain fault output (overtemp/overcurrent flag)
11	`A1`	Motor Output	Bipolar stepper motor coil A phase 1
12	`A2`	Motor Output	Bipolar stepper motor coil A phase 2
13	`B2`	Motor Output	Bipolar stepper motor coil B phase 2
14	`B1`	Motor Output	Bipolar stepper motor coil B phase 1
15	`GND`	Power	Motor Ground reference
16	`VMOT`	Power	Motor supply voltage (+8.2 V to +45 V DC)

Microstep resolution selection

The microstep mode is selected via inputs M0, M1, and M2. All three pins have internal $100\text{ k}\Omega$ pull-down resistors (defaulting to Full-step when left floating):

`M0`	`M1`	`M2`	Microstep Resolution
Low	Low	Low	Full step
High	Low	Low	1/2 step
Low	High	Low	1/4 step
High	High	Low	1/8 step
Low	Low	High	1/16 step
High	Low	High	1/32 step
Low	High	High	1/32 step
High	High	High	1/32 step

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Motor Supply Voltage	$V_{MOT}$	8.2	24.0	45.0	V	Motor power rail
Logic Level Input High	$V_{IH}$	2.0	3.3 / 5.0	5.25	V	`STEP`, `DIR`, `ENABLE`, `M0-M2`
Logic Level Input Low	$V_{IL}$	-0.3	0	0.8	V	`STEP`, `DIR`, `ENABLE`, `M0-M2`
Phase Current (Uncooled)	$I_{out}$	—	1.5	1.8	A	Natural convection
Phase Current (Cooled)	$I_{out\_cooled}$	—	2.0	2.2	A	Heatsink + forced air cooling
Minimum Pulse Width	$t_{STEP}$	1.9	—	—	µs	`STEP` high/low pulse duration
Thermal Shutdown Temp	$T_{TSD}$	150	160	175	°C	Junction temperature shutdown

Current limiting calibration ( $V_{ref}$ )

Before running a motor, the phase current limit must be set using the onboard trimmer potentiometer ( $V_{ref}$ measured between the potentiometer metal wiper and GND):

$I_{trip} = \frac{V_{ref}}{2 \times R_{sense}} = \frac{V_{ref}}{2 \times 0.100\ \Omega} = 5 \times V_{ref}$

(Assuming standard $R_{sense} = 0.100\ \Omega$ current sense resistors on the module PCB)

Example: To limit current to $1.0\text{ A}$ per phase:

$V_{ref} = 1.0\text{ A} \times 0.2 = 0.20\text{ V} = 200\text{ mV}$

Wiring

DRV8825 Pin	Arduino / MCU	External Power	Notes
`VMOT`	—	+12V to +36V DC	Motor power supply rail
`GND` (Motor)	—	Power Supply GND	Bulk decoupling capacitor mandatory
`GND` (Logic)	MCU GND	Power Supply GND	Shared ground reference
`STEP`	Digital Pin (e.g. D3)	—	Step pulse signal
`DIR`	Digital Pin (e.g. D4)	—	Direction signal
`RESET` & `SLEEP`	—	—	Connect `RESET` directly to `SLEEP`

Warning

LC Voltage Spike Hazard:

Connecting or disconnecting a stepper motor while the DRV8825 is powered will destroy the driver IC.
A bulk electrolytic decoupling capacitor (minimum $47\ \mu\text{F}$ to $100\ \mu\text{F}$ , 50V rated) MUST be placed across VMOT and GND close to the module pins to suppress destructive ceramic capacitor LC voltage spikes.

Common mistakes

Leaving RESET and SLEEP floating: Both pins must be pulled High (or shorted together) for the driver to function. If left un-connected, the chip remains locked in sleep mode.
Hot-plugging motors: Unplugging motor cables while VMOT power is connected causes inductive kickback spikes that instantly destroy the output MOSFET H-bridges.
Confusing DRV8825 orientation with A4988: Although the DRV8825 fits in the same 16-pin socket, the potentiometer faces the opposite direction relative to VMOT compared to an A4988 StepStick. Plugging it in upside down shorts the power rails.

Notes

A4988 vs DRV8825: DRV8825 supports higher voltage (45V vs 35V), higher current (2.2A vs 2.0A max), higher microstepping (1/32 vs 1/16), and has a lower $R_{DS(on)}$ resulting in less heat generation at equivalent currents.

Interface	STEP/DIR Control
Package	28-pin HTSSOP / StepStick Module