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LMZ31704: Switching frequency

Part Number: LMZ31704

Hi,

For lower output voltages, lower switching frequencies are recommended for LMZ31704. I am assuming this is to satisfy a minimum on-time requirement for internal FET switch. Can I opt for higher values of switching frequency for lower voltages? (For a specific case of VIN=12V, VOUT=0.9V, Can I choose switching frequency of 1000KHz, as against 250khz mentioned in datasheet?. This will help in reducing the current ripple and in turn reduce voltage ripple, for a given set of caps)

What is the minimum on-time requirement, if any, for the internal switch?

  • The minimum ON time of the internal controller can be as high as 165 ns, which limits the switching frequency at lower output voltages. The switching frequency ranges listed in Table 7 also account for tolerances on input voltage rail. I would not recommend operating higher than 350kHz for your application.