April 5, 2011
This new pre-driver IC is targeted at the office automation, telecommunications, consumer, and industrial markets.
The external MOSFETS can be PWM’d with the ENABLE input or with the internal PWM current regulator. In both cases the A4938 synchronous rectification feature will turn on the appropriate MOSFET(s) during current decay to reduce power dissipation. The A4938 uses low cost Hall elements with noise filtering to prevent false commutation signals. A 5 V regulated supply output is provided to power the three HALL elements. Internal circuit protection includes thermal shutdown with hysteresis, under voltage lockout, over voltage protection with two voltage settings, locked rotor and dead time protection. Special power up sequencing is not required. Operating temperature range is -40°C to 85°C.
The A4938EETTR-T is supplied in a 5 mm × 5 mm 28-lead QFN package with exposed thermal pad. This small footprint package is lead (Pb) free with 100% matte tin leadframe plating.
Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide. Further information about Allegro can be found at www.allegromicro.com.