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ADP2301 outputs 2.5V instead of 5V

Question asked by MathiasVandel on May 15, 2017
Latest reply on May 22, 2017 by Migs

Hi 

 

I am trying to make a DCDC converter using the ADP2301. The design is more or less taken from the design tool ADP230x_BuckDesigner_Release.xlsm. 

 

Down below is a picture of my circuit: 

DCDC circuit

 

I was hoping to get 5V as output, but instead i am seeing 2-2.5V with a lot of ripple. (see picture below) 

Output

 

Here is some more scope pictures for you to understand what is going on. 

 

At BST pin: 

BST

 

Enable pin:

Enable

 

Feedback pin: 

Feedback

 

And here is the PCB layout. Underneath is a solid GND plane. 

PCB layout

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Can anybody help me out here? I am a bit confused about the feedback pin. From the datasheet the regulation voltage is 0.8V which it is designed to be at 5V. Why am i seeing almost 2V when my output is 2.5V? 

I have no load at the output, does that have an impact? 

 

Best,

Mathias

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