The input pins of the UCC27524 gate-driver devices are based on a TTL and CMOS compatible input-threshold logic that is independent of the VDD supply voltage. With typically high threshold = 2V and typically low threshold = 1 V, the logic level thresholds are conveniently driven with PWM control signals derived from 3.3-V and 5-V digital power-controller devices. Wider hysteresis (typ 1 V) offers enhanced noise immunity compared to traditional TTL logic implementations, where the hysteresis is typically less than 0.5 V. UCC27524 devices also feature tight control of the input pin threshold voltage levels which eases system design considerations and ensures stable operation across temperature (refer to Typical Characteristics). The very low input capacitance on these pins reduces loading and increases switching speed.

The UCC27524 device features an important protection feature that holds the output of a channel when the respective pin is in a floating condition. This is achieved using GND pulldown resistors on all of the non-inverting input pins (INA, INB), as shown in the device block diagrams.

The input stage of each driver is driven by a signal with a short rise or fall time. This condition is satisfied in typical power supply applications, where the input signals are provided by a PWM controller or logic gates with fast transition times (<200 ns) with a slow changing input voltage, the output of the driver may switch repeatedly at a high frequency. While the wide hysteresis offered in UCC27524 definitely alleviates this concern over most other TTL input threshold devices, extra care is necessary in these implementations. If limiting the rise or fall times to the power device is the primary goal, then an external resistance is highly recommended between the output of the driver and the power device. This external resistor has the additional benefit of reducing part of the gate-charge related power dissipation in the gate driver device package and transferring it into the external resistor itself.