Datasheet

VCC

Gate

Voltage

Boost

Narrow Pulse at

each Turn On

Anti Shoot-

Through

Circuitry

Input Signal

NMOS

, Pull Up

OUT

UCC27518

UCC27519

SLUSB33 –MAY 2012

www.ti.com

Output Stage

The UCC27518 and UCC27519 are capable of delivering 4-A source, 4-A sink (symmetrical drive) at VDD = 12

V. The output stage of the UCC27518 and UCC27519 devices are illustrated in Figure 21. The UCC27518 and

UCC27519 devices features a unique architecture on the output stage which delivers the highest peak source

current when it is most needed during the Miller plateau region of the power switch turn-on transition (when the

power switch drain/collector voltage experiences dV/dt). The device output stage features a hybrid pull-up

structure using a parallel arrangement of N-Channel and P-Channel MOSFET devices. By turning on the N-

Channel MOSFET during a narrow instant when the output changes state from low to high, the gate-driver device

is able to deliver a brief boost in the peak-sourcing current enabling fast turn on.

Figure 21. UCC2751x Gate Driver Output Structure

The R

parameter (see ELECTRICAL CHARACTERISTICS) is a DC measurement and it is representative of

the on-resistance of the P-Channel device only, since the N-Channel device is turned on only during output

change of state from low to high. Thus the effective resistance of the hybrid pull-up stage is much lower than

what is represented by R

parameter. The pull-down structure is composed of a N-Channel MOSFET only. The

parameter (see ELECTRICAL CHARACTERISTICS), which is also a DC measurement, is representative of

true impedance of the pull-down stage in the device. In UCC27518 and UCC27519, the effective resistance of

the hybrid pull-up structure is approximately 1.4 x R

The driver output voltage swings between VDD and GND providing rail-to-rail operation, thanks to the MOS

output stage which delivers very low dropout. The presence of the MOSFET body diodes also offers low

impedance to switching overshoots and undershoots. This means that in many cases, external Schottky diode

clamps may be eliminated. The outputs of these drivers are designed to withstand 500-mA reverse current

without either damage to the device or logic malfunction.

Product Folder Link(s): UCC27518 UCC27519