DRV8825 stepper driver: specs and pinout
A bipolar stepper motor driver with a built-in microstepping indexer: one pulse on STEP moves the motor one (micro)step and DIR sets the direction. This page covers the DRV8825 chip; the module board is not covered by an official document.
Specs
| Spec | Value | Source |
|---|---|---|
| Motor supply VM | 8.2 V to 45 V (all VM pins on the same supply) | source Recommended Operating Conditions (p.4); Pin Functions (p.3) |
| Output current | 2.5 A maximum drive current per output with proper heat sinking, at 24 V and 25 C | source Features and Description (p.1) |
| Microstepping | Full, 1/2, 1/4, 1/8, 1/16 and 1/32 step, set by MODE0-MODE2 | source Table 1 Stepping Format (p.13) |
| Logic input levels | VIH 2.2 V min (5.25 V max); VIL 0.7 V max | source Electrical Characteristics, logic-level inputs (p.5) |
| Maximum STEP frequency | 250 kHz; STEP high and low pulse each at least 1.9 us | source Timing Requirements (p.6) |
| VM operating supply current | 5 mA typ, 8 mA max at VM 24 V; sleep mode 10 uA typ, 20 uA max | source Electrical Characteristics (p.5) |
| Built-in 3.3 V output | 3.3 V (3.2-3.4 V) on V3P3OUT, 0 to 1 mA load; can supply VREF | source Electrical Characteristics (p.5); Pin Functions (p.3) |
| Internal pulldowns | About 100 kohm on STEP, DIR, nRESET, nENBL and MODE pins; 1 Mohm on nSLEEP | source Electrical Characteristics (p.5); nRESET, nENBL and nSLEEP Operation (section 8.3.6) |
| Protection | Overcurrent, thermal shutdown, VM undervoltage lockout; fault reported on nFAULT | source Features (p.1); Protection Circuits (section 8.3.7) |
| Absolute maximum junction temperature | -40 C to 150 C | source Absolute Maximum Ratings (p.4, operating junction temperature range row) |
| Current limit setting | Full-scale chopping current ICHOP = V(xREF) / (5 x RISENSE); example in the sheet: 0.25 ohm sense resistor and VREF 2.5 V gives 2 A. The module's sense resistor value is not documented. | source Current regulation, Equation 1 (section 8.3.2) |
| Thermal protection and heat sinking | Thermal shutdown: section 11.3 says the device is disabled if the die exceeds approximately 150 C; the electrical table lists tTSD (thermal shutdown temperature) as 160 C min to 180 C max. The sheet gives both figures, so keep the die well below the lower one. Entering shutdown means excessive power dissipation, insufficient heat sinking or high ambient temperature. 2.5 A per output needs proper heat sinking. | source Thermal Protection and Heatsinking (sections 11.3, 11.3.2); Electrical Characteristics table, tTSD row (p.5) |
Power
| Value | Source | |
|---|---|---|
| Supply | Motor supply VM 8.2 V to 45 V; logic inputs accept 2.2 V and above | source Recommended Operating Conditions (p.4); Electrical Characteristics (p.5) |
| Current | 5 mA typ from VM at 24 V (motor current not included) | source Recommended Operating Conditions (p.4); Electrical Characteristics (p.5) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
Rows are the DRV8825 chip's pins. The module board (header labels and order, which pins it brings out, the sense resistors and how its current limit is set) is not covered by an official document, so check the printed labels and set the current limit before connecting a motor.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VMA / VMB | Bridge A and bridge B power supply (motor supply) | 8.2-45 V | Both pins to the same supply, bypassed with 0.1 uF and bulk capacitance | source Pin Functions (p.3) |
| GND | Device ground | source Pin Functions (p.3) | ||
| AOUT1 / AOUT2 | Bridge A outputs | Connect to bipolar stepper winding A | source Pin Functions (p.3-4) | |
| BOUT1 / BOUT2 | Bridge B outputs | Connect to bipolar stepper winding B | source Pin Functions (p.3-4) | |
| STEP | Step input: a rising edge moves the indexer one step | VIH 2.2 V min, VIL 0.7 V max | Internal pulldown | source Pin Functions (p.3); Electrical Characteristics (p.5) |
| DIR | Direction input: level sets the stepping direction | VIH 2.2 V min, VIL 0.7 V max | Internal pulldown | source Pin Functions (p.3) |
| nENBL | Enable input: low enables outputs, high disables them | VIH 2.2 V min, VIL 0.7 V max | Internal pulldown | source Pin Functions (p.3) |
| nRESET | Reset input, active low; also disables the H-bridge outputs | VIH 2.2 V min, VIL 0.7 V max | Must be high to operate; internal pulldown | source Pin Functions (p.3); section 8.3.6 |
| nSLEEP | Sleep input: high enables the device, low enters low-power sleep | VIH 2.2 V min, VIL 0.7 V max | Must be high to operate; wait about 1 ms after waking before STEP | source Pin Functions (p.3); section 8.3.6 |
| MODE0 / MODE1 / MODE2 | Microstep mode select (Table 1) | VIH 2.2 V min, VIL 0.7 V max | Internal pulldowns | source Pin Functions (p.3); Table 1 (p.13) |
| nFAULT | Fault output, open drain: low on overtemperature or overcurrent | VOL 0.5 V max at 5 mA | Needs a pull-up if read | source Pin Functions (p.3); Electrical Characteristics (p.5) |
Build with it
Project ideas for the DRV8825 stepper driver. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Camera slider: A 12 V supply is inside the 8.2-45 V motor range; the Uno's 5 V outputs clear the 2.2 V input-high level. Add bulk capacitance on VM and set the module's current limit first. Check the NEMA 17 motor label for its rated phase current (this page has no sourced figure) and set the module's current limit (VREF) to that value or lower, using the sheet's ICHOP = VREF / (5 x RISENSE) with your module's sense resistor; the 2.5 A chip figure needs heat sinking, so fit a heatsink. Choose a motor and current setting whose draw from the supply stays within what the 12 V 2 A adapter can deliver. Put the stocked 1000 uF 25 V electrolytic across VM, close to the module with the polarity right (25 V is well above 12 V); the sheet gives no value, so check the supply for ripple or dips when the motor starts.
- ESP32 turntable: ESP32 3.3 V outputs are above the 2.2 V input-high level, so STEP and DIR can be driven directly; the motor runs from its own 12 V supply. Check the NEMA 17 motor label for its rated phase current (this page has no sourced figure) and set the module's current limit (VREF) to that value or lower, using the sheet's ICHOP = VREF / (5 x RISENSE) with your module's sense resistor; the 2.5 A chip figure needs heat sinking, so fit a heatsink. Choose a motor and current setting whose draw from the supply stays within what the 12 V 2 A adapter can deliver. Put the stocked 1000 uF 25 V electrolytic across VM, close to the module with the polarity right (25 V is well above 12 V); the sheet gives no value, so check the supply for ripple or dips when the motor starts.
- Pico step counter demo: The Pico's 3.3 V outputs meet the input-high level; a button steps the motor one revolution at a chosen microstep setting. Learning project. Check the NEMA 17 motor label for its rated phase current (this page has no sourced figure) and set the module's current limit (VREF) to that value or lower, using the sheet's ICHOP = VREF / (5 x RISENSE) with your module's sense resistor; the 2.5 A chip figure needs heat sinking, so fit a heatsink. Choose a motor and current setting whose draw from the supply stays within what the 12 V 2 A adapter can deliver. Put the stocked 1000 uF 25 V electrolytic across VM, close to the module with the polarity right (25 V is well above 12 V); the sheet gives no value, so check the supply for ripple or dips when the motor starts.
- Mega stepper test bench: The three MODE pins let firmware pick full to 1/32 step; the LCD shows the selected mode. Check the NEMA 17 motor label for its rated phase current (this page has no sourced figure) and set the module's current limit (VREF) to that value or lower, using the sheet's ICHOP = VREF / (5 x RISENSE) with your module's sense resistor; the 2.5 A chip figure needs heat sinking, so fit a heatsink. Choose a motor and current setting whose draw from the supply stays within what the 12 V 2 A adapter can deliver. Put the stocked 1000 uF 25 V electrolytic across VM, close to the module with the polarity right (25 V is well above 12 V); the sheet gives no value, so check the supply for ripple or dips when the motor starts.
Common mistakes
- Leaving nSLEEP or nRESET low: both must be driven high for the device to operate, and each has an internal pulldown, so a floating pin keeps it asleep or in reset (source)
- Leaving VM without bypass and bulk capacitance, or splitting the two VM pins across supplies: the datasheet says both pins go to the same supply, bypassed with 0.1 uF and connected to appropriate bulk capacitance (source)
- Running a motor with no current limit set or no heat sinking: the 2.5 A per output figure needs proper heat sinking, and the chip enters thermal shutdown if it overheats (about 150 C in section 11.3; 160-180 C in the electrical table); set VREF so the chopping current matches the motor's rated phase current and fit a heatsink (source: link, Features p.1; sections 8.3.2 and 11.3)
Not covered by the official source
- Module board is not covered by an official document: header labels, sense resistor value, how the current limit (VREF) is set and whether nSLEEP/nRESET are tied together are unknown.
- Only values from the recommended-operating and electrical tables are quoted.
- Only the control, supply and output pins are listed; the chip's charge-pump, current-sense and VREF pins are not necessarily exposed on the module.
- NEMA 17 phase current is not sourced on its own page; ideas tell the reader to check the motor label. The TI sheet says bulk capacitance is required but gives no value (section 10.1: size it by testing); the ideas use the stocked 1000 uF 25 V electrolytic as a starting value, which is the page's choice, not a sheet figure. The sheet's thermal-shutdown figure differs between section 11.3 (about 150 C) and the electrical table (160-180 C).
Sources
- link (Texas Instruments DRV8825 datasheet, SLVSA73F, April 2010 - revised July 2014)