Input/output Fileter for DC-DC power module

[flote21]

Hello folks!

i am wondering about which input/output filtering stage is better to use
for sensing applications where I need a very low switching noise and
FPGA power supply tree. I need to convert from 24v to 5.5v and from 24v
to 16v and Iout=2A. I have been thinking about these parts:

LMZ23603 (TI)
WPMDM1500602JT (Würth Electronic)
ADP3050 (AD)
LTM4609 (LT)

Another question is about the swithing frequency. I need to use 4 power
modules in my POWER board, is it better to run all the power modules
with the same switching frequency? Because if i dont have any big
problem, related with the noise for example, I can use the same stage
filtering for all the power modules.

If someone has a good recommendation for a power supply module with good
performance, please don't hesitate to tell me.

Thanks.

 

[jiripolivka]

Most switching DC-DC and AC-DC converters are poorly designed and generate a lot of interference which can travel "backwards" to the source as well as "forward" to the load.
If sensitive devices are powered like PLOs and lower-frequency LNAs, I recommend to avoid using switched power supplies at all. If you insist, find either a commercial EMI-compliant filter, or design yours according to EMI specifications.
Many poor DC-DC converter switch from 10 kHz up to more than 1 MHz. Harmonics are radiated and nobody cares.
Please design a good low-pass filter with a pole at your switching frequency, and TEST it. Reduce all interference as well as you can. Very soon such switchers will kill many good projects as electronics grows more sensitive.