Output stage and interface
The DRV2603RUNT: The half-bridge output configuration (two outputs) drives the actuator differentially — the ERM or LRA sees the full supply swing across its terminals, not a single-ended pulse. This doubles the available voltage swing compared to a single-ended drive at the same supply rail. Control is via a parallel interface or a PWM input, giving the host MCU flexibility: a dedicated PWM timer pin can drive the haptic waveform directly, or the parallel port can set the drive level with a few GPIO lines.
Thermal and package considerations
The supply and load connections share the same 2.5 V to 5.2 V range, so the PCB layout needs only one power rail and a single decoupling capacitor close to the VDD pin — no split-plane or charge-pump routing.