The UC3524DW is a high-frequency switching regulator, and proper PCB layout is crucial for its operation. TI recommends a 4-layer PCB with a solid ground plane, and the use of vias to connect the top and bottom layers. The input and output capacitors should be placed close to the IC, and the switching node should be kept as short as possible. Additionally, a shielded inductor is recommended to reduce EMI.
The minimum input voltage is determined by the voltage drop across the internal switch and the output voltage. A general rule of thumb is to add 1-2V to the output voltage to ensure proper operation. The maximum input voltage is limited by the absolute maximum rating of the IC, which is 30V. However, it's recommended to operate the IC at a maximum input voltage of 25V to ensure reliability and reduce stress on the internal components.
The soft-start pin (SS) is used to control the output voltage rise time during startup. By connecting a capacitor from the SS pin to ground, the output voltage will rise slowly, reducing the inrush current and preventing output voltage overshoot. The value of the capacitor determines the soft-start time, with larger values resulting in slower rise times.
The UC3524DW requires a compensation network to ensure stability. A type II compensation network is recommended, which consists of a series resistor and capacitor connected from the output to the compensation pin (COMP). The values of the resistor and capacitor depend on the output voltage, output capacitance, and switching frequency. TI provides a compensation calculator tool to help designers determine the optimal values.
The maximum output current capability of the UC3524DW is dependent on the input voltage, output voltage, and switching frequency. The IC can deliver up to 4A of output current, but this may require additional heat sinking and careful thermal design. It's recommended to consult the datasheet and application notes for guidance on output current capability and thermal design.
UC3524DW datasheet
by Texas Instruments
