Given the justified interest these days in power devices of all types — silicon MOSFETs, silicon-carbide (SiC) MOSFETs, and IGBTs — it’s important to remember that a power device is only as good as its driver. Depending on the design of the circuitry, the driver has multiple roles beyond sourcing current to the power device to turn it on, or sinking current to turn it off.

Both turn-on and turn-off must be done “crisply” with suitable rise and fall times despite gate capacitance and without overshoot or other artifacts. Doing this is often difficult, and it’s especially challenging in the automotive environment with its wide temperature swings that cause significant changes in critical electrical characteristics and associated performance.

Addressing these needs is the Littelfuse IX4352NEAU 9-A low-side gate driver for SiC MOSFETs and IGBTs (Fig. 1). This driver is rated to AEC-Q100 Grade 1 for an operational ambient temperature range of −40 to +125°C, along with an operating voltage range V_DD-V_SS up to 35 V. It’s also rated for human body model (HBM) ESD Classification 2 (±2 kV).

The separate source and sink outputs allow for tailored turn-on and turn-off timing while minimizing switching losses. An internal negative-charge regulator provides a user-selectable negative gate-drive bias for high dV/dt immunity and faster turn-off (Fig. 2).

The IX4352NEAU has three gate-drive outputs. Two power outputs, OUTSRC and OUTSNK, are each rated for a maximum peak current of 9 A while the third output, OUTSOFT, is rated for a typical peak current of 900 mA.

Separate source and sink high-current outputs enable independent adjustment of the discrete power SiC MOSFET or IGBT turn-on and turn-off transactions by means of a single resistor for each output. An internal non-adjustable dead time prevents cross conduction between the source and sink outputs (Fig. 3).

Desaturation detection circuitry senses an overcurrent condition of the SiC MOSFET and initiates a soft turn off, thus preventing a potentially damaging dV/dt event. The non-inverting logic input, IN, is TTL- and CMOS-compatible; internal level shifters provide the necessary bias to accommodate negative gate-drive bias voltages.

Additional protection features include UVLO detection and thermal shutdown. An open-drain FAULT output signals a fault condition to the microcontroller. On-state propagation delay (t_ON) is 70 ns while off-state propagation delay (t_OFF) is 65 ns.

The IX4352NEAU comes in a narrow SOIC-16 with a bottom-side pad. Its 16-page datasheet provides a full range of static and dynamic characteristics as well as tables and graphs showing performance vs. temperature and other operating points, including supply voltage, frequency, and load capacitance.