RT1020 vs RT1040 (LQFP vs BGA)

[Frank2201]

We plan to use RT10xx microcontroller for our project.

I asked around about difference of PCB development and assembly between by LQFP and BGA package.

There is quite a price increase for 4 layer PCB and component assembly on both sides of PCB.

I find out that one type of RT1040 can be put on 2 layer PCB. So, my only question is here, can i put decoupling capacitors only on top side of PCB?

Is this allowable or i should expect problems if the decoupling capacitors are not near BGA pins.

Or i should stick with the RT1020?

[Frank2201]

OK, thank you for answer.

I know how troublesome can be certification around EMI, so better to use RT1021.

[vicentegomez]

this is our recomendation

Place the small decoupling capacitors and the larger bulk capacitors on the bottom side of the CPU. The
0402 decoupling capacitors and the 0603 bulk capacitors must be placed as close as possible to the
power balls. Placing the decoupling capacitors close to the power balls is critical to minimize inductance
and ensure the high-speed transient current demand of the processor

[Frank2201]

Thank you for your answer.

Yes, I read that in hardware recommendation already.

I wanted to find out if I can put RT1040 on PCB design where the components are only on top side.

From recommendation, i know that mostly BGA design need PCB assembly with components on both side.

I need only simple answer YES or NO to use RT1040 on PCB that have components only on one side?

[vicentegomez · Accepted solution]

there is no simple answer.

The recommendation is NO

You can put the capacitor only on one side, yes, but you need to check if you do not have problems with noise or EMI in the field, or if you need to pass some certification maybe won't be possible meet all the spec for the certification.