Worcester, Mass. - Targeting automotive and industrial markets, Allegro Microsystems Inc.'s A3940 predriver IC for large-brush dc motors provides four high-current gate-drive outputs capable of driving a wide range of n-channel power MOSFETs. The device uses bootstrap capacitors to provide the above-battery-supply voltage needed for n-channel FETs. An internal charge pump allows for 100 percent duty cycle operation of the bridge. Phase and enable input terminals are provided to control the speed and direction of a dc motor from external pulse-width modulation control signals.
The chip is protected against undervoltage and overvoltage, thermal-shutdown and motor lead short-to-supply and short-to-ground conditions. The A3940 is priced at $2.46 each in 1,000-piece quantities, and has an eight-week lead time. The chip comes in either a 28-lead TSSOP thermally enhanced package or in a standard 28-lead SOIC.
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