uC current draw (simple question)

Discussion in 'General Electronics Chat' started by Pootworm, May 22, 2007.

  1. Pootworm

    Thread Starter Member

    May 18, 2007
    The maximum power supply current that my ATtiny13 draws at the speed and voltage I'm running is listed as ~6mA.

    This means that it acts as a source of ~100kohm resistance (at 5V), not that I need to construct a circuit somehow that will provide it with exactly 6mA, correct? It will draw what it needs, and I just have to make sure the amperage is available for it?

    Thanks in advance!
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Not at all. You can put it on any 5 volt source that is well-regulated and will supply more than the 6 ma stated. The device will only draw the current it needs.

    Wall transformers are not good chouces, as their regulation is notoriously poor. Something like a 78L05 regulator being fed with anything over 7 volts DC should work. The regulator is good for way more than your 6 mills.
  3. Papabravo


    Feb 24, 2006
    You should be careful. Besides the quiescent current required, the current draw of a complex circuit like a microprocessor depends on a number of things, like temperature, clock speed, and how much current the outputs are sourcing or sinking. I would be careful with a stated maximum that did not have some conditions associated with that number.

    One, often overlooked fact, is that supply voltage and clock speed have a squared relationship to power consumption. Thats why 3.3V @ 4MHz may be more attractive then 5V @ 12 MHz.