ADP2301 outputs 2.5V instead of 5V

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: 

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

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

At BST pin: 

Enable pin:

Feedback pin: 

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

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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

Parents
  • Hi Ryang and Migs, 

    When testing this I have had a 20 cm wire going from the DC/DC converter to my load (resistor). I was measuring the voltage at the resistors terminals, where I see a smaller voltage from what i would expect.

    I then tried to measure the voltage directly on the output of the regulator, and of course it is outputting a solid 5V and sourcing 1A easily. 

    Sorry about my lack of knowledge - and again a big thanks for your time. 

    Best,

    Mathias

Reply
  • Hi Ryang and Migs, 

    When testing this I have had a 20 cm wire going from the DC/DC converter to my load (resistor). I was measuring the voltage at the resistors terminals, where I see a smaller voltage from what i would expect.

    I then tried to measure the voltage directly on the output of the regulator, and of course it is outputting a solid 5V and sourcing 1A easily. 

    Sorry about my lack of knowledge - and again a big thanks for your time. 

    Best,

    Mathias

Children
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