ZHCSN09A June 2021 – September 2022 LM5168-Q1 , LM5169-Q1
PRODUCTION DATA
The LM5168P-Q1 and LM5169P-Q1 are designed for buck applications by operating in DEM mode, with light load PFM operation. Figure 9-14 shows the schematic for a 5-V output buck regulator capable of delivering 300 mA of load current, using the LM5168P.
In this data sheet, the effective value of capacitance is defined as the actual capacitance under D.C. bias and temperature, not the rated or nameplate values. Use high-quality, low ESR, ceramic capacitors with an X5R or better dielectric throughout. All high value ceramic capacitors have a large voltage coefficient in addition to normal tolerances and temperature effects. Under D.C. bias, the capacitance drops considerably. Large case sizes and higher voltage ratings are better in this regard. To help mitigate these effects, multiple capacitors can be used in parallel to bring the minimum effective capacitance up to the required value. This can also ease the RMS current requirements on a single capacitor. A careful study of bias and temperature variation of any capacitor bank must be made to ensure that the minimum value of effective capacitance is provided.