BBB (rev.0) Voltage drop

[LimesPone]

Hi!

(Noob question below )

I have an older BBB rev.0 board, currently powered by the USB FTDI cable. At the FTDI cable pins, I read 5V. On the other side of the board, however, at the +5V/GND pins, I read ~3.57V. Is this drop expected?

(I should note also that I opted for a 7805a voltage regulator when constructing this board, years ago.)

The real issue that leads me to this question is that I'm trying to drive a chip that requires 4.75 to 11V supply voltage. So it seems that the voltage drop across the BBB results in a V that is outside of that range.

Thanks!

[oz]

LimesPone,

The problem is the 7805, that voltage drop is about right for that device. Grab a more modern LDO such as a LM2940 or LM9931 (5v model) and put it in and you'll be fine. However you need to carefully check the inputs and outputs with a meter and compare to the pinout of the device you are putting in, to get it installed correctly.

Hope that helps,

Paul

[JudgeDup]

I see what youre saying... but now that poses another question... Those are incoming power, so what voltage are you feeding it?

[oz]

I need a few more details to understand the question.

Paul