data/text/DLP3/898364

UC3825: Switching frequency

Part Number: UC3825 Hi team, Could you provide the equation for frequency configuration with RT, CT ? And are there any application report to know more detail to design circuit with UC3825 ? Thank you and best regards, Michiaki

Hi Michiaki, I didn't find a equation for the frequency of UC3825, you can design the frequency according the figure of "Timing Resistance vs Frequency " in page 6 of datasheet. It is more accurate than the equation. I only found one UC3825 application note for your reference, <secret URL>/lit/an/slua053/slua053.pdf but I think it is more like a power note. If you want to verify the calculation and design, it is a good solution to use a simulation module which is available online. <secret URL>/product/UC3825/toolssoftware Regards, Teng

Hi Teng, Does customer need cut and try on TINA and design without equation ? Thank you and best regards, Michiaki

Hi Michiaki, Yes, customer can select the RT and CT according the figure of "Timing Resistance vs Frequency " in page 6 of datasheet. And I recommend to use a simulation to rectify the result if they want. Regards, Teng

Hi Teng, Could you kindly advise what difference is between UC3825 and UC3825A/B ? We can find the more detail in the datasheet of UC3825A/B. Should we recommend UC3825A/B instead of UC3825? Thank you and best regards, Michiaki

Hi Michiaki, In most applications, the UC3825A/B devices are enhanced drop-in replacements for UC3825a/B high speed PWMs. We can recommend UC3825A/B to customer instead of UC3825. The differences can be easily found in the attached document. And also datasheet. <secret URL>/lit/an/slua125/slua125.pdf Regards, Teng