Allegro Microsystems, Inc. Announces New Full-Bridge MOSFET Pre-Driver IC

Targeted to Drive High Current Brush DC Motors in Portable Applications

Worcester, MA - Allegro MicroSystems, Inc, announces a new full-bridge MOSFET controller for use with external N-channel power MOSFETs. The A4957 is designed for applications with high-power brush DC motors. It has a wide supply voltage range of 7 V to 50 V. This new device is targeted for commercial and industrial applications such as portable power tools, lawn and garden equipment, industrial blowers, lifts and conveyors, and forklifts.

Offered in the 24 lead ES package, Allegro's A4957 is intended to meet the performance and price point driving motors in these applications. A unique charge pump regulator provides full ( >10 V ) gate drive for supply voltages down to 7 V or as low as 4.5 V with a reduced gate drive. A bootstrap capacitor is used to provide the above battery supply voltage required for N-channel MOSFETs. A unique bootstrap charge management system ensures that the bootstrap capacitor is always sufficiently charged to supply the high-side gate drive circuit. Each of the power MOSFETs is controlled independently but all are protected from shoot-through by dead time that can be configured by the user through an external resistor. Integrated diagnostics provide indication of undervoltage and over-temperature faults.

The A4957SESTR-T is supplied in a 24-lead, 4 mm × 4 mm × 0.75 mm QFN package with an exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte tin lead-frame plating (suffix T).

Allegro MicroSystems, Inc. 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

Featured Product

Allied Motion - New MFH170i Housed Brushless Torque Motor Has Integrated Servo Drive and Optical Encoder

Allied Motion - New MFH170i Housed Brushless Torque Motor Has Integrated Servo Drive and Optical Encoder

Allied Motion's Megaflux MFH170i series of 170 mm (6.7 in) diameter housed brushless torque motors consists of a high performance brushless DC torque motor, a digital servo drive, and an optical encoder, all integrated into a rugged machined aluminum housing with robust duplex bearings. The MFH0170i series features a 63.5 mm (2.5 in) large-bore through shaft, and is characterized by a very high torque-to-inertia ratio. There are three stack lengths in the series with peak torque ranging from 8.5 up to 16.9 Nm (75 up to 150 lb-in). The standard winding voltage is 48 V. And to ease the hassle of long leadtimes for prototypes, the new MFH170i is now available through our QuickShip program.