I have to design a dc-dc based on the LM60430.
I would like to calculate the output capacitor and I am used to do it with the cut-off frequency of the loop. Here I do not have this information so I must use the formula given in the datasheet.
I use the "Equation 5" to check Cout. First thing I have done is to check that I type the formula correctly by using the data of the example.
In the example, we have:
- Vin = 12V
- Vout = 5V
- IoutMax = 4A
- deltaIout = 4A
- fsw = 400kHz
- Expected deltaVout in transient = 0.3V
- K for inductor calculation = 0.3 -> real K=0.27 after inductor selection @ 6.8uH
By doing that, I find that Cout > 93uF and ESR <66mohm while datasheet gives Cout > 86uF and ESR <22mohm. (using Cout of 86uF in the formula gives 324mV of deltaVout!)
I checked the same formula with the example of the LM63635 and there it is spot on. So I guess I type my formula correctly.
Would it be possible for someone to double-check the example in the datasheet ?