Fault in MIC29302UW(MIC29302UW is not giving correct output)

aman kumar's picture

Offline

Joined: Dec 16, 2020

Replies: 1
Fault in MIC29302UW(MIC29302UW is not giving correct output)
December 16, 2020 - 1:49pm

I am using MIC29302UW IC for converting 12V to 3.8V. I am using this IC from last 2 years and have used this LDO in more than 50 devices. But the same IC is not working in my new PCB board. I even made a small PCB, only for testing the working of MIC29302UW,but its not showing the correct output. 

Let me explain the issue- I am providing 12V at the input of MIC29302UW and using 100k(R1) and 47.7(R2) resistors to form feedback loop. But instead of getting 3.8V(approx.), its showing 12V at the output pin. The input voltage is not stepping down from 12V to 3.8V.
So, what i can do to rectify this error and make it working? I have bought this LDO IC from DIGI-KEY. So, i am hoping that there is no fault in the IC.

 

NOTE: I am using the original MIC29302UW from DIGI-KEY.

Sourav Gupta's picture

Offline

Joined: Feb 12, 2018

Replies: 585

There is a Passing Transitor inside the LDO.

 

It can only happen if the passing transistor is not controlled or being shorted.

 

If you connected the LDO in reverse direction or make the output as shorted then you possibly fired it up. Thus check this one first.

You need to use the EN pin. This is also required to be controlled. Did you checked it or left it floating?

Hope your LDO is good and construction is bad rather that construction is good and the LDO is bad.

aman kumar's picture

Offline

Joined: Dec 16, 2020

Replies: 1

The problem is solved, the issue was because i haven't connected any load on the output side so it was giving abrupt output voltage.I connected one led at the output terminal to pass the minimum required current and it worked.