Datasheet

UCC27323

GND

INB

INA

OUTA

VDD

OUTB

INPUT

0.1 µF

Ceramic

2.2 µF

V = 12 V

LOAD

UCC27323-Q1, UCC27324-Q1, UCC27325-Q1

SLUS678A –MARCH 2008–REVISED APRIL 2012

www.ti.com

It should be noted that the current-sink capability is slightly stronger than the current source capability at lower

. This is due to the differences in the structure of the bipolar-MOSFET power output section, where the

current source is a P-channel MOSFET and the current sink has an N-channel MOSFET.

In a large majority of applications, it is advantageous that the turn-off capability of a driver is stronger than the

turn-on capability. This helps to ensure that the MOSFET is held off during common power-supply transients that

may turn the device back on.

Parallel Outputs

The A and B drivers may be combined into a single driver by connecting the INA/INB inputs together and the

OUTA/OUTB outputs together. Then, a single signal can control the paralleled combination as shown in Figure 4.

Figure 4.

Operational Waveforms and Circuit Layout

Figure 5 shows the circuit performance achievable with a single driver (half of the 8-pin device) driving a 10-nF

load. The input pulse width (not shown) is set to 300 ns to show both transitions in the output waveform. Note the

linear rise and fall edges of the switching waveforms. This is due to the constant output current characteristic of

the driver as opposed to the resistive output impedance of traditional MOSFET-based gate drivers.

Sink and source currents of the driver are dependent upon the VDD value and the output capacitive load. The

larger the VDD value the higher the current capability, and the larger the capacitive load the higher the current

sink/source capability. Trace resistance and inductance, including wires and cables for testing, slows down the

rise and fall times of the outputs which reduces the current capabilities of the driver. To achieve higher current

results, reduce resistance and inductance on the board as much as possible and increase the capacitive output

load value in order to swap out the effect of the inductance values.