APU4D4 Supply voltage range

  • I would not advise exceeding 12v. That said based on p14-15 of the schematic.

    The 3.3v reg APW8713A by spec can take up to 28v in

    The 5v reg APW8715a by spec can take up to 28v in

    But that is just 2 components.

    Without digging more I am willing to bet it was designed with parts with a bit of range. The problem is will it produce the proper output with a higher input? Not sure.

    If it were me I would make certain to keep it at 12. I am assuming you have an application where it would be easier to feed it more. A cheap $10-20 buck/boos converter could take 8-40v in and turn it into 12V within 1.5% or tighter if you dig for a good one and pay a smidge more. If you were looking to do POE then there are splitters that will get it down to 12v/2a just like the original AC adapters.

  • Hi, thanks for the reply. The reason is I am intending to use this in a vehicle application and the vehicle voltage is likely to vary from 11 to 17 volts. With similar applications I have used vehicle laptop supplies to stabilize the voltage, but in general these have an output range of 15-21v. I will try to find a 12v device.



  • Some devices are more tolerant. With the shortage of parts for these boards and them being generally hard to get now..

    Something along this line may do what you need. https://www.amazon.com/Convert…ransformer/dp/B08D8L79TS/

    That's not a referral or a recommendation, just a suggested starting point. With buck to lower voltage and boost to raise it when it drops (like during cold cranking) it may protect the device from;

    Key on (+12v), start boot-->engine crank, voltage(+10v) drop, APU shuts back off>post crank(+13.8-14v) power up again.

    Good luck! These apu would make a great mobile vehicle AP/Router.