The UC2844AQDR is a high-frequency switching regulator, and as such, it requires careful PCB design and layout to minimize noise, EMI, and parasitic inductance. TI recommends using a 4-layer PCB with a solid ground plane, separating the high-current and high-frequency nodes, and using short, wide traces for the power lines. Additionally, it's essential to follow the recommended component placement and orientation to minimize radiated emissions.
Choosing the right inductor for the UC2844AQDR involves considering factors such as inductance value, saturation current, and core material. TI recommends using an inductor with an inductance value between 1.5uH and 3.3uH, and a saturation current rating of at least 2A. The core material should be ferrite or iron powder, and the inductor should have a low DC resistance to minimize power losses.
The UC2844AQDR has an absolute maximum input voltage rating of 18V, but TI recommends operating it within the recommended input voltage range of 12V to 15V for optimal performance and reliability. Exceeding the maximum input voltage can cause damage to the device or affect its performance.
The UC2844AQDR's voltage feedback loop requires compensation to ensure stability and prevent oscillations. TI recommends using a Type II compensation network, which consists of a series resistor and capacitor connected between the VFB pin and the output voltage. The values of the resistor and capacitor depend on the specific application and output voltage, but a good starting point is R = 1kΩ and C = 10nF.
The UC2844AQDR has a built-in soft-start circuit that limits the inrush current during startup. The soft-start time is approximately 1ms, but it can be adjusted by adding an external capacitor between the SS pin and ground. The soft-start time can be calculated using the formula t_ss = 1.1 * C_ss * R_ss, where C_ss is the external capacitor value and R_ss is the internal resistance of the SS pin.
UC2844AQDR datasheet
by Texas Instruments
