The UCC3801DTR is a high-frequency device, so it's essential to follow good layout practices to minimize noise and ensure proper operation. Place the device close to the power stage, use a solid ground plane, and keep the input and output traces short and separate. TI provides a recommended layout in the application note SLUA271.
The choice of resistors for the voltage feedback network depends on the desired output voltage and the input voltage range. TI recommends using 1% or 0.1% tolerance resistors to ensure accuracy. A good starting point is to use a 2.2 kΩ resistor for RFBT and a 1 kΩ resistor for RFB. Adjust these values based on your specific application requirements.
The maximum allowed voltage on the VCC pin is 15 V. Exceeding this voltage can damage the device. Ensure that the voltage on the VCC pin is within the recommended operating range of 8.5 V to 14 V.
To ensure the overcurrent protection is triggered correctly, make sure the sense resistor (RS) is properly sized and connected. The sense resistor should be placed close to the power stage, and its value should be chosen based on the maximum allowed current and the desired overcurrent threshold.
The soft-start pin (SS) is used to control the output voltage ramp-up during startup. By connecting a capacitor from the SS pin to ground, you can slow down the output voltage rise time, reducing inrush currents and electromagnetic interference (EMI).
UCC3801DTR datasheet
by Texas Instruments
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