Datasheet

VCC

Gate

Voltage

Boost

Narrow Pulse at

each Turn On

Anti Shoot-

Through

Circuitry

Input Signal

NMOS

, Pull Up

OUT

UCC27517

UCC27516

SLUSAY4C – MARCH 2012–REVISED MAY 2013

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Enable Function

As mentioned earlier, an enable/disable function is easily implemented in the UCC27516 and UCC27517 using

the unused input pin. When IN+ is pulled down to GND or IN- is pulled down to VDD, the output is disabled.

Thus IN+ pin is used like an enable pin that is based on active-high logic, while IN- can be used like an enable

pin that is based on active-low logic.

Output Stage

The UCC27516 and UCC27517 are capable of delivering 4-A source, 4-A sink (symmetrical drive) at VDD = 12

V. The output stage of the UCC27516 and UCC27517 devices are illustrated in Figure 23. The UCC27516 and

UCC27517 devices features a unique architecture on the output stage which delivers the highest peak-source

current when most needed during the Miller-plateau region of the power-switch turnon transition (when the

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

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

delivers a brief boost in the peak-sourcing current enabling fast turnon.

Figure 23. UCC2751x Gate Driver Output Structure

The R

parameter (see ELECTRICAL CHARACTERISTICS) is a DC measurement and 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 pullup stage is much lower than what is

represented by R

parameter. The pulldown structure is composed of a N-Channel MOSFET only. The R

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

impedance of the pulldown stage in the device. In the UCC27516 and UCC27517, the effective resistance of the

hybrid pullup structure is approximately 1.4 × R

The driver-output voltage swings between VDD and GND providing rail-to-rail operation because of 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 Links: UCC27517 UCC27516