TM4C129ENCPDT: Stabilizing Voltage capacitor

Nishitha Chandrasekar

Part Number: TM4C129ENCPDT
Other Parts Discussed in Thread: LM3940

Hi Charle sir,

I have doubt related to capacitor selection near the 5v input power connector. I am designing a control card which has 5V input with 1A and also i am using voltage regulator from 5v to 3.3v.

We are using 5v with 40A SMPS. Then how to calculate the capacitor value near this 5v input power connector.

over 5 years ago

0 Charles Tsai over 5 years ago

TI__Guru**** 159385 points

Hi Nishitha,

Which 5v to 3.3V regulator are you using?

Please refer to the TM4C129 launchPad schematic for ideas. If you look at it, it has a 0.1uF cap on the 5v input. However, the cap on the input is optional according to the TPS datasheet. So I will suggest you consult the datasheet of your chosen voltage regulator and see what is recommended.

0 Nishitha Chandrasekar over 5 years ago in reply to Charles Tsai

Intellectual 700 points

Hi Sir,

I am using LM3940 voltage regulator.They mentioned 0.47uf input side of the regulator in the datasheet . When i verified to design a control card related to my application most of them using additionally 470uf /16v capacitor for filtering the noise due to power supply. But no one gave how they calculate the exact value of 470uf

0 Charles Tsai over 5 years ago in reply to Nishitha Chandrasekar

TI__Guru**** 159385 points

HI Nishitha,
Your question can be best answered by the Linear Regulators forum in the below link since the experts there know their products much better than us. Do you mind to post new question there or I can forward your post to that forum.
e2e.ti.com/.../321

Arm-based microcontrollers

Arm-based microcontrollers forum

TM4C129ENCPDT: Stabilizing Voltage capacitor