The A4990 is a dual full-bridge driver for stepper motors and small brush DC motors in automotive applications. Each full bridge uses DMOS power devices with integrated freewheeling diodes. Control circuits prevent cross-conduction, or shoot-through, when switching between high-side and low-side drives.
This device drives stepper motors with full current in either direction in each phase, allowing two-phase on, full-step operation. It drives DC motors in both directions and has brake capability. A single input turns-off both bridges, allowing motors to coast. All control modes can be achieved using 3, 4, or 5 outputs from a standard parallel interface of a microcontroller.
The peak motor current can be limited by sense resistor selection, providing higher efficiency, reduced motor heating, and longer motor life.
The outputs are protected from short circuits to supply and to ground, and low load-current detection is included. Chip level protection includes: overtemperature shutdown, and overvoltage and undervoltage lockout.
The A4990 is supplied in a 20-lead TSSOP power package with an exposed thermal pad (package type LP). This package is lead (Pb) free with 100% matte tin lead frame plating.