ZHCSTB0E February 2010 – November 2023 UCC27321-Q1 , UCC27322-Q1
PRODUCTION DATA
The IN threshold has a 3.3-V logic sensitivity over the full range of VDD voltage; yet, it is equally compatible with 0-V to VDD signals. The inputs of UCC2732x-Q1 family of drivers are designed to withstand 500-mA reverse current without either damage to the device or logic upset. In addition, the input threshold turnoff of the UCC2732x-Q1 is slightly raised for improved noise immunity. The input stage of each driver must be 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). The IN input of the driver functions as a digital gate, and is not intended for applications where a slow-changing input voltage is used to generate a switching output when the logic threshold of the input section is reached. While this may not be harmful to the driver, the output of the driver may switch repeatedly at a high frequency.
Users must not attempt to shape the input signals to the driver in an attempt to slow down (or delay) the signal at the output. If limiting the rise or fall times to the power device is desired, then an external resistance can be added between the output of the driver and the load device, which is generally a power MOSFET gate. The external resistor may also help dissipate power from the device package, as discussed in Section 11.3.