Allegro MicroSystems Inc. (Worcester, MA) announced its new A3935 power MOSFET pre-driver IC for large three-phase brushless dc motors. The IC is designed for the automotive and industrial/factory automation markets. With maximum operating temperature specifications to +135 degrees C, the A3935 is designed to operate in the harsh under-hood environment of automotive applications such as engine cooling and electronic power steering.
The A3935 has an on-board boost converter designed to allow operation of the pre-driver IC in low-battery conditions while still maintaining adequate gate drive voltage. The A3935, with an operating voltage range from 7V to 40V, is a good choice for systems where either 12V or 24V batteries are in use. The A3935 features an adjustable over-voltage feature, which protects the IC if motor supply voltages exceed a user-set voltage with a range of 19.4V to 40V.
Additional automotive and industrial features include fault reporting and diagnostics, including short-to-battery and short-to-ground detection using drain-to-source monitoring of the external n-channel MOS transistors. Three fault-output reporting pins are used to help the system controller diagnose and decode the cause of the fault and take the appropriate action.
The A3935 is supplied in either a 44-lead plastic PLCC with four copper batwing tabs for maximum heat dissipation, or in a 36-lead QSOP package. The A3935 has an eight-week lead time and is priced at $3.26 per part for quantities of 10,000.
