What the DRV8870DDA is and what it drives
The Texas Instruments DRV8870DDA is a fully integrated motor driver that combines the control logic and power stage in a single NMOS half-bridge pair. It handles brushed DC motors and unipolar stepper motors, accepting a PWM interface from a microcontroller or motion controller. The load voltage range spans 6.5 V to 45 V.
3.6 A continuous output — sizing the load
The 3.6 A continuous output current sets the practical motor size this driver can handle. The PowerPad package is designed to pull heat into the PCB copper plane.
Supply and logic voltage — separate rails
The logic supply (VDD) runs from 0 V to 5.5 V. The load supply (VM) is the 6.5 V to 45 V rail that powers the motor.
Package and mounting — 8-PowerSOIC with PowerPad
The DRV8870DDA comes in an 8-PowerSOIC package with a 3.90 mm body width and a PowerPad on the underside. It is a surface-mount part, shipped in Tube form. The PowerPad is the primary thermal path; the PCB footprint should include a copper pad and at least four thermal vias to the ground plane.
For new designs, this part carries no supply-risk flag.