why we place a pi low pass filter as shown in the photo for External Supply for Analog Circuits in the MCU

 

Why do you think it's done?

 

I worked with an ARM Cortex M3 microcontroller and in the schematic of this microcontroller there is a pi filter linked to external supply

 

Let's be Socratic -- shall we?

What characteristic does that particular filter have?

1. Low Pass
2. High Pass
3. Bandpass
4. Bandreject (aka Notch)

 

Low pass filter

 

And what effect does a low pass filter on transients?

Bob

 

Hint: Digital circuits create a lot of noise that does its best to get into analog circuits.

 

Very good it is a lowpass filter. Next questions.

What is the corner frequency of this lowpass filter?

1. 159 Hz.
2. 440 Hz
3. 1591 Hz.
4. 3125 Hz.

What is the order of the filter?

1. 2nd Order
2. 3rd Order
3. 4th order
4. 5th order

What kind of lowpass is it?

1. Chebyshev
2. Bessel
3. Elliptical
4. Butterworth
5. none of the above

 

i ask fo this reason Bob

 

Hint: Digital circuits create a lot of noise that does its best to get into analog circuits.

its role then is to avoid noise