Spark Logic

DRV8825 bipolar stepper motor driver connection guide

DRV8825 bipolar stepper motor driver HTSSOP-28 (PWP) wiring guide with power, signal assignments, and bench checks.

HTSSOP-28 (PWP)

29 contacts Current package

Texas Instruments · 9.7 × 4.4 mm nominal molded body, 0.65 mm lead pitch.

Verify power and current limiting

Required

Power this fixture from 12 V with the motor disconnected. Hold nENBL high, nRESET low and STEP low. Bring nSLEEP high with the 3.3 V controller when the motor supply is stable.

CBULK 100 µF / 25 V between 12 V motor rail and Ground12 V motor railCBULK 100 µF / 25 VGround
CA 100 nF / 25 V at VMA between 12 V motor rail and Ground12 V motor railCA 100 nF / 25 V at VMAGround
CB 100 nF / 25 V at VMB between 12 V motor rail and Ground12 V motor railCB 100 nF / 25 V at VMBGround
CFLY 10 nF / 50 V between Flying capacitor terminal 1 and Flying capacitor terminal 2Flying capacitor terminal 1CFLY 10 nF / 50 VFlying capacitor terminal 2
CCP 100 nF / 16 V between Pump output and 12 V motor railPump outputCCP 100 nF / 16 V12 V motor rail
RCP 1 MΩ between Pump output and 12 V motor railPump outputRCP 1 MΩ12 V motor rail
C3V3 470 nF / 6.3 V between 3.3 V current reference and Ground3.3 V current referenceC3V3 470 nF / 6.3 VGround
RSA 1.3 Ω / 1 W between Bridge A sense and GroundBridge A senseRSA 1.3 Ω / 1 WGround
RSB 1.3 Ω / 1 W between Bridge B sense and GroundBridge B senseRSB 1.3 Ω / 1 WGround
RF 10 kΩ between 3.3 V current reference and Fault status3.3 V current referenceRF 10 kΩFault status

Bench checks

  • Measure about 3.3 V at V3P3OUT and both VREF inputs while awake.
  • For 1.3 Ω sense resistors, the nominal full-scale current is 3.3 V ÷ (5 × 1.3 Ω) ≈ 0.51 A. Choose a motor whose winding ratings accommodate the measured trip current.

Texas Instruments SLVSA73F, §§ 6, 7.5, 8.3.6 and Equation 4. The 12 V supply and 1.3 Ω sense resistors are fixture choices.

Connection scenarios

Drive a bipolar stepper in full-step mode

Power down before connecting the windings. Identify the two pairs with an ohmmeter. Use a small bipolar motor rated for at least 0.6 A per winding with inductance suitable for PWM current regulation.

CBULK 100 µF / 25 V between 12 V motor rail and Ground12 V motor railCBULK 100 µF / 25 VGround
CA 100 nF / 25 V at VMA between 12 V motor rail and Ground12 V motor railCA 100 nF / 25 V at VMAGround
CB 100 nF / 25 V at VMB between 12 V motor rail and Ground12 V motor railCB 100 nF / 25 V at VMBGround
CFLY 10 nF / 50 V between Flying capacitor terminal 1 and Flying capacitor terminal 2Flying capacitor terminal 1CFLY 10 nF / 50 VFlying capacitor terminal 2
CCP 100 nF / 16 V between Pump output and 12 V motor railPump outputCCP 100 nF / 16 V12 V motor rail
RCP 1 MΩ between Pump output and 12 V motor railPump outputRCP 1 MΩ12 V motor rail
C3V3 470 nF / 6.3 V between 3.3 V current reference and Ground3.3 V current referenceC3V3 470 nF / 6.3 VGround
RSA 1.3 Ω / 1 W between Bridge A sense and GroundBridge A senseRSA 1.3 Ω / 1 WGround
RSB 1.3 Ω / 1 W between Bridge B sense and GroundBridge B senseRSB 1.3 Ω / 1 WGround
RF 10 kΩ between 3.3 V current reference and Fault status3.3 V current referenceRF 10 kΩFault status

Bench checks

  • With all MODE pins low, release reset, wait at least 2 ms after waking and drive nENBL low. Start with a 10 Hz square wave at STEP.
  • Confirm that nFAULT is high and the shaft advances steadily. In full-step mode each winding uses about 71% of the programmed full-scale current.
  • If the motor vibrates without turning, disconnect power and check that each winding uses one bridge. Switch off before changing wiring.

Texas Instruments SLVSA73F, § 8.4, Table 1 and § 9.2. Starting step rate is a fixture choice.

HTSSOP-28 (PWP) wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

Top view, with pin 1 on the upper left. The exposed thermal pad is underneath the body.
EP is the exposed center pad on the underside.
Selected pin details

2 · CP2

Bidirectional · Bidirectional

Second flying-capacitor terminal. Keep the capacitor close to both leads.

Texas Instruments SLVSA73F, Section 6

Electrical limits · Pin in the reference

Models and documents

This pinout is for the bare PWP IC. A carrier board has its own connector order and sense resistors.

DRV8825PWP
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPR
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPR.A
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPR.B
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPRG4
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPRG4.A
PWP0028C pinout and exposed PowerPAD.
DRV8825PWPRG4.B
PWP0028C pinout and exposed PowerPAD.
  • Texas Instruments SLVSA73F· Rev. F. Pin functions, timing, mode truth table, current regulation and layout.
  • Source register· Document revisions, applicable order codes, consulted sections and available file checksums.