The A4957 is a full-bridge controller for use with external N-channel power MOSFETs and is specifically designed for applications with high-power inductive loads such as brush DC motors. A unique charge pump regulator provides full ( >10 V ) gate drive for battery voltages down to 7 V and allows the A4957 to operate with a reduced gate drive, down to 4.5 V. 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.

The drivers are available in the industry-standard 8-pin SO footprint and pin configuration with a thermally enhanced 8-pin SO package. All devices operate over the -40°C to +125°C automotive temperature range. Applications Telecom Power Supplies Synchronous Buck DC-to-DC Converters Half-Bridge, Full-Bridge, and Two-Switch Forward Converters. Renesas' large portfolio of driver products comprises half-bridge, full-bridge, low-side, and synchronous buck MOSFET drivers. The bridge driver products handle voltages up to 100V, with industry-leading gate rise and fall times and exceptional input-to-output propagation delay performance.

Each of the power MOSFETs is controlled independently but all are protected from shoot-through by dead time that is userconfigured by an external resistor. Integrated diagnostics provide indication of undervoltage and overtemperature faults. The A4957 is supplied in a 24-contact 4 mm × 4 mm × 0.75 mm QFN with an exposed pad for enhanced thermal dissipation.

It is lead (Pb) free, with 100% matte tin leadframe plating (suffix –T).

Ozzy osbourne albums. 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). It is priced at $1.42 in quantities of 1,000.

Part Number: A4957.