IC remove need for bootstrap capacitors

An Allegro Microsystems product story

Edited by the Electronicstalk editorial team Jun 18, 2008

The A3942 is designed to drive four N-channel MOSFETs in a high-side configuration with gate drive outputs that use a current-source topology, eliminating the need for bootstrap capacitors.

The A3942 from Allegro MicroSystems Europe is a four-channel high-side MOSFET control/driver IC designed to provide an efficient interface between a system controller and the high-current inductive loads typically found in automotive engine control systems.

The A3942 complements Allegro's existing automotive MOSFET pre-driver family.

It is designed to drive four N-channel MOSFETs in a high-side configuration with gate drive outputs that use a current-source topology, eliminating the need for bootstrap capacitors.

The new device offers a high degree of flexibility for automotive engine control systems.

It is designed to operate over a voltage range of 4.5 to 60V and over the full automotive temperature range, making it suitable for both 12 and 24V engine control systems.

The four outputs can be controlled with either four parallel input lines or through an integrated serial peripheral interface (SPI).

The serial interface greatly increases the flexibility of the IC by allowing software control of channel-specific blanking times for short to ground detection.

Extensive fault protection and diagnostic capabilities include the use of the serial port to output a wide range of diagnostic signals to the controller via a serial data output pin.

The A3942 provides full protection against open-load, short to ground and short to battery events and reports all diagnostics back to the controller.

Shortcircuit fault thresholds can be adjusted on a "per channel" basis with inexpensive external resistors.

Multiple A3942 devices can share an SPI interface by either connecting them in parallel or in a "daisy chained" series using the chip select pin to address the appropriate IC.

A sleep mode is provided to reduce the quiescent current draw to less than 10mA.

The A3942 is supplied in the automotive 38L TSSOP package.