L4960 switching frequency

EMart.10 · ‎2022-11-09

HI! I have a L4960 switching regulator, I want to know if there is a formula to calculate the switching frequency in fuction of the resistor and capacitor connected to pin 5. Also if you know more information about the pin 3 and pin 6 functionalitys it will be very helpful.

Thank you.

Peter BENSCH · ‎2022-11-10

Welcome, @Community member, to the community!

First of all, the L4960 is already discontinued and unfortunately there is no support for it anymore.

Nevertheless, I will try to help you a little further because I had to deal with this many years ago. There is no formula for the switching frequency, but the data sheet contained a resistance vs. frequency diagram for different capacitor values. As far as I remember, you could set a switching frequency between 600...10kHz with 1.5nF and a resistor between 1...68kOhm, both connected in parallel and to GND.

Pin 3 was the frequency compensation pin for the control loop, typically 15kohms + 33nF in series to GND.

Pin 6 is connected to a capacitor for soft start, typically 2.2µF to GND, which is charged linearly by the pin 6 source current of about 140µA. This capacitor also influences the short-circuit current, but no more detailed information is available on this.

Does it answer your question?

Regards

/Peter

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View solution in original post

Peter BENSCH · ‎2022-11-10

Welcome, @Community member, to the community!

First of all, the L4960 is already discontinued and unfortunately there is no support for it anymore.

Nevertheless, I will try to help you a little further because I had to deal with this many years ago. There is no formula for the switching frequency, but the data sheet contained a resistance vs. frequency diagram for different capacitor values. As far as I remember, you could set a switching frequency between 600...10kHz with 1.5nF and a resistor between 1...68kOhm, both connected in parallel and to GND.

Pin 3 was the frequency compensation pin for the control loop, typically 15kohms + 33nF in series to GND.

Pin 6 is connected to a capacitor for soft start, typically 2.2µF to GND, which is charged linearly by the pin 6 source current of about 140µA. This capacitor also influences the short-circuit current, but no more detailed information is available on this.

Does it answer your question?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

EMart.10 · ‎2022-11-11

Yes, thank you very much!

Peter BENSCH · ‎2022-11-11

Great!

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.