A microstepping bipolar stepper driver in HTSSOP-28, the higher-spec sibling of the A4988 on 3D-printer and CNC boards. Its integrated indexer runs a motor from just STEP and DIR pulses (no phase tables), and three mode pins select full down to 1/32 microstepping (finer than the A4988's 1/16). Two N-channel bridges deliver up to 2.5 A per coil from an 8.2 to 45 V supply (higher than the A4988), with a simple current-limit set by VREF and sense resistors, an internal 3.3 V reference output, and full protection: over-current, over-temperature, and under-voltage lockout. It is pin-and-module compatible with the A4988 footprint used on stepstick boards. The 3D model shown is a representative TSSOP-28 body; the real package is HTSSOP-28 with a thermal pad.

Pinout

Pin	Name	Type	Function
1	CP1	passive	Charge pump flying capacitor terminal 1. Connect a 0.01-uF 50-V ceramic capacitor between CP1 and CP2.
2	CP2	passive	Charge pump flying capacitor terminal 2. Connect a 0.01-uF 50-V ceramic capacitor between CP1 and CP2.
3	VCP	power_out	High-side gate drive voltage (charge pump output). Connect a 0.1-uF 16-V ceramic capacitor to VM and a 1-MOhm resistor to VM.
4	VMA	power_in	Bridge A power supply (8.2 to 45 V). Must be tied to the same supply as VMB; bypass with a 0.1-uF cap to GND plus appropriate bulk capacitance.
5	AOUT1	output	Bridge A output 1. Connect to bipolar stepper motor winding A. Positive winding current flows AOUT1 -> AOUT2. Rated for up to 2.5 A continuous.
6	ISENA	passive	Bridge A ground / current-sense return. Connect the low side of bridge A through the current-sense resistor for bridge A to GND.
7	AOUT2	output	Bridge A output 2. Connect to bipolar stepper motor winding A. Positive current is AOUT1 -> AOUT2.
8	BOUT2	output	Bridge B output 2. Connect to bipolar stepper motor winding B. Positive current is BOUT1 -> BOUT2.
9	ISENB	passive	Bridge B ground / current-sense return. Connect the low side of bridge B through the current-sense resistor for bridge B to GND.
10	BOUT1	output	Bridge B output 1. Connect to bipolar stepper motor winding B.
11	VMB	power_in	Bridge B power supply (8.2 to 45 V). Must be tied to the same supply as VMA; bypass with a 0.1-uF cap to GND plus appropriate bulk capacitance.
12	AVREF	input	Bridge A current-set reference input. Reference voltage for winding-A regulated current. Normally AVREF and BVREF are tied together; can be driven from V3P3OUT. Recommended VREF range 1 to 3.5 V.
13	BVREF	input	Bridge B current-set reference input. Reference voltage for winding-B regulated current. Normally tied to AVREF.
14	GND	power_in	Device ground. Also connect the exposed PowerPAD (PPAD) to GND for thermal dissipation.
15	V3P3OUT	power_out	Internal 3.3-V LDO regulator output (3.2/3.3/3.4 V typ, up to 1 mA load). Bypass to GND with a 0.47-uF 6.3-V ceramic capacitor. Can be used to supply VREF.
16	nRESET	input	Active-low reset input. Initializes the indexer logic and disables the H-bridge outputs when low. Internal pulldown.
17	nSLEEP	input	Sleep-mode input. Logic high enables the device; logic low enters low-power sleep. Internal pulldown. tWAKE = 1.7 ms from nSLEEP high to STEP accepted.
18	nFAULT	output	Open-drain fault output. Logic low when a fault condition (overtemperature, overcurrent) is present. Requires external pullup. VOL = 0.5 V max at IO = 5 mA.
19	DECAY	input	Decay-mode select input. Low = slow decay; open (floating) = mixed decay; high = fast decay. Has both internal pullup (~130 kOhm) and pulldown (~80 kOhm) so the floating state resolves to mid-rail (mixed).
20	DIR	input	Direction input. Logic level sets the stepping direction. Internal pulldown (~100 kOhm).
21	nENBL	input	Enable input. Logic high disables the outputs and indexer operation; logic low enables. Internal pulldown.
22	STEP	input	Step input. A rising edge causes the internal indexer to advance one microstep. Internal pulldown. fSTEP up to 250 kHz; min high/low pulse 1.9 us.
23	NC	unconnected	No internal connection. Leave this pin unconnected.
24	MODE0	input	Microstep-mode select bit 0. Together with MODE1/MODE2 sets full, 1/2, 1/4, 1/8, 1/16, or 1/32 step. Internal pulldown.
25	MODE1	input	Microstep-mode select bit 1. Together with MODE0/MODE2 sets the microstep resolution. Internal pulldown.
26	MODE2	input	Microstep-mode select bit 2. Together with MODE0/MODE1 sets the microstep resolution. Internal pulldown.
27	nHOME	output	Open-drain home-position output. Logic low when the indexer is at the home state of the step table. Requires external pullup.
28	GND	power_in	Device ground. Second ground pin; connect together with pin 14 and the PowerPAD.
PAD	PPAD	power_in	Exposed thermal PowerPAD on the package bottom. Must be soldered to the PCB ground plane for thermal performance and connected to GND.

Key specifications

Parameter	Value
Type	Bipolar stepper motor driver
Output	2 N-channel full-bridges
Current	up to 2.5 A/coil (with cooling)
Microstepping	full to 1/32 (MODE0-2)
Control	STEP + DIR indexer
Motor supply	8.2-45 V
Protection	OCP + OTP + UVLO
Package	HTSSOP-28 (thermal pad)

Ordering variants

Same part, different packaging or reel option.

DRV8825PWPR (HTSSOP-28)
DRV8825 module (stepstick)

CAD (KiCad official)

Symbol: DRV8825 (generated from datasheet; KiCad has no symbol)
Footprint: Package_SO:HTSSOP-28-1EP_4.4x9.7mm_P0.65mm
3D model: TSSOP-28 (representative; real package HTSSOP-28)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (36 pp, sha256 5b4dccc2497334e1, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF