Powering custom Teensy 3.2 from 9v 500ma wall adapter

[yeahtuna]

I have a custom Teensy design using a MCP1825S-3302E/DB as a power regulator. I have a request from customers to allow the device to be powered from a 9v 500ma wall wart, which is typical for audio gear.

I searched the forums here but couldn't really find anything. Anyone have any idea how I should drop that 9v down for interfacing with the MCP1825? Should I be looking for a different regulator? Any tips or schematics would be great.

Rob

 

[Constantin]

All comes down to the power needed. If you need the 500mA that the MCP1825 can allegedly produce (with an ideal PCB layout and so on) then have at least 2 choices:

1) Find a more suitable voltage regulator that can handle the higher input-output voltage delta (i.e something like the LD 1117 series). Pay attention to heat management though.
2) A DC-DC switchmode power supply like the Recom ROF-78xx series, which can either take you down to 3.3V directly (if your application can handle the ripple) or 'just' 5VDC and then the MCP1825 can take over.

 

[yeahtuna]

Maybe something like this? Not sure about the caps. Probably have more than I need.

 

[Constantin]

That's certainly one way to do it. However, I wonder if you have the polarities on the power jack reversed. Most jacks are positive on the inside, GND on the outside.