0
\$\begingroup\$

I am designing a PCB but in my country it is hard to find components. As I am beginner, I am afraid to use similar components so I wanted to ask you.

enter image description here

I couldn't find this micro USB, I am using this (probably this is okay.)

I couldn't find the NCP1117. I am thinking of using an LM1117 or AMS1117 SOT223 package. Are those okay? I worked with the LM1117 in TO-220 package before. If it is okay I will use it with 10uF and 100uF decoupling capacitors. I found one NCP1117 but I don't know if is it here.

One more question, can I use the VBUS as 5V without add any resistors or capacitors?

\$\endgroup\$
13
  • 2
    \$\begingroup\$ As a beginner, you're doubting everything. The micro USB is a connector. "Micro USB is a standard so that part of the connector should always be OK, the part with the pads that are soldered to the PCB might be different. To know what you get: study the datasheet. \$\endgroup\$ Commented Oct 19, 2021 at 14:01
  • \$\begingroup\$ "in my country it is hard to find components" Digikey, Mouser, Farnell and RS ship all over the world. Design with what you need, not what's locally available. \$\endgroup\$
    – winny
    Commented Oct 19, 2021 at 14:02
  • 2
    \$\begingroup\$ LM1117 and LM1117 are voltage regulators, they should be compatible but again consult the datasheet. Their footprint on the PCB could be (slightly) different. But since these devices are very standard (used everywhere) you are unlikely to have issues. \$\endgroup\$ Commented Oct 19, 2021 at 14:04
  • 1
    \$\begingroup\$ If it is okay I will use it with 10uF and 100uF decoupling capacitors Look in the datasheet of the component that you're going to use! You will have to learn to read the datasheet anyway. Don't try to understand everything all at once (you WILL go crazy), focus on what you understand and what you think is relevant. \$\endgroup\$ Commented Oct 19, 2021 at 14:05
  • \$\begingroup\$ @Bimpelrekkie you are right but I used to 220package with those capacitors. That's why I thought it is okay. \$\endgroup\$ Commented Oct 19, 2021 at 14:07

2 Answers 2

0
\$\begingroup\$

The NCP1117 datasheet allows for a ceramic output capacitor.

A 10 uF ceramic or tantalum capacitor should be adequate for most applications

The LM1117 specifies as follows:

The ESR of the output capacitor should range between 0.3 Ω to 22 Ω.

Which rules out most ceramic capacitors. You can use a 10uF ceramic capacitor with a 1 ohm resistor in series.

\$\endgroup\$
1
  • \$\begingroup\$ Thank you for your comment. \$\endgroup\$ Commented Oct 19, 2021 at 18:20
0
\$\begingroup\$

In addition to what others have mentioned, do note that the USB standard limits C1 to 10uF maximum. If you increase it, your device may cause overcurrent protection to trigger in USB hosts or hubs, and turn your device off prematurely.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.