Allegro MicroSystems, Inc. Introduces New Full-Bridge MOSFET Pre-Driver IC
Small Profile Package with Fault Diagnostics and Reporting

Worcester, MA – April 28, 2009 — Allegro MicroSystems, Inc. has added a new full-bridge MOSFET pre-driver IC with fault diagnostics and reporting to their existing family of full-bridge controllers. Allegro’s A4940 contains a flexible input interface, bootstrap monitor circuit, wide operating voltage (5.5 to 50 V) and temperature (40°C to +150°C) ranges, in a very small profile package. It is designed for automotive 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 will allow the A4940 to operate with a reduced gate drive down to 5.5 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.
 

Each of the power MOSFETs are controlled independently but are protected from shoot-through by resistor programmable dead time. Integrated diagnostics provide an indication of under voltage and over temperature faults.
 

The A4940 is supplied in a 24-pin TSSOP power package with an exposed thermal pad (package type LP). This package is available in lead (Pb) free versions, with 100% matte-tin leadframe plating (suffix –T).