Power ground vs ground pin

Discussion in 'General Electronics Chat' started by tle24, Oct 23, 2008.

  1. tle24

    Thread Starter New Member

    Oct 23, 2008
    2
    0
    Hi.
    I am a newbie to electronics and I am working on a microcontroller project where I want to sample the analog output coming from an analog sensor. Since this project is all battery based, the voltage supply to the analog sensor has to be constant, so I chose to use the TSP63000 buck boost converter from texas instruments.
    The microprocessor is powered by 2 AA batteries (1.5 x 2 = 3v ). The basic idea is to drive constantly the analog sensor with, say, 3V even if we are down to 2.0 volts coming from the battery. The micro works fine even when we are down to 1.8 volts.
    I am baffled by the usage of the power ground and ground pins when I looked at the datasheet. I suppose by ground we mean analog ground, is that correct? How does power ground pin come into play in the schematics?
    Thanks in advance for any clarification.
    I include the datasheet for your convenience
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Assuming you refer to the first illustration, all the internal grounds are common. The pin labeled 'ground' is the tie point where the external logic ground is connected. While that point is also common to all the other grounds, the logic ground should connect as close to the pin as possible.
     
  3. tle24

    Thread Starter New Member

    Oct 23, 2008
    2
    0
    Thank you. Yes, I was referring to the very first illustration (page 1). The circuit depicted on that page is quite suitable to my design. (3.3 volts that that need) Thanks again
     
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