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Help Selecting Devices

Other Parts Discussed in Thread: SN74AHC1G08, SN74AHC1G32, TL331-Q1, TLV760
I need help selecting devices for a circuit consisting of:
preferably in the form of a Dual Inline Package. 
This is for managing power in a raspberry pi project.
If there is a single chip that incorporates all these functions, that would be ideal.
If not then I am happy to work with discrete devices.
If these are not available in DIP form then I am willing to work with a different type of package.
If the project produces a good result then I have a market to sell a lot of these devices.
The logic gates and the comparator will be powered by 3.3 volts and must produce about 3.3 volts when the logic signal is high.
These devices will be used for communication with 3.3 volt GPIO input and output pins on the raspberry pi.
One of the voltage regulators will be used to power the chips mentioned above. 
Voltage regulation of some type is necessary because power for the chips will vary between 3.3 and 5.5 volts depending on whether batteries are powering the circuit or if the 5.5 volt power supply is plugged in.
Ideally, the inputs on the logic gates and the comparator will be 5.5 volt tolerant and the outputs will provide about 3.3 volts. If this is the case then I will not need anything else.
If on the other hand, the inputs on the logic gates and the comparator are not tolerant of 5.5 volts then I will need some means of regulating the voltage to their inputs. This is because the input voltages might be a 3.3 volts or 5.5 volts depending on whether the 3.3 volt battery or the 5.5 volt power supply is being used at the time.
Would you please help me select devices that meet the above criteria?
Thanks for your help,
  • Hi John,

    Did you try using our parametric search on the website?

    You will have to search for each type of device separately (For example, AND gates are located under Logic -> AND Gates and Comparators are located under Amplifiers -> Comparators) but you can put all the requirements you listed above into the search and narrow the parts list down, including package, voltage, and technology family.

    I went into the AND Gate parametrics search page and built an example search for you. Probably the hardest part about selecting a device will be choosing between the different technology families (for logic, at least).

    In my search, there are parts from the HC and AHC families, both of which would work for your requirements. You can read about the differences in our Logic Guide.

    As for power requirements, that's a much more complex topic. If you just want linear regulators, you can find those in LDOs, but I would recommend trying out the Webench Design Center, where you can enter your requirements and get a ton of options to meet your power needs.

  • Hi Emrys,

    Thanks for showing me the search example, and for helping me chose a logic family.

    Also, I knew I needed a regulator, but if you hadn't pointed me to LDOs, I never would have found what I was looking for.

    The Logic Guide was most useful for choosing the package type.

    I finally settled on the following devices.

    [SN74AHC1G08 Single 2-Input Positive-AND Gate DBV Package 5-Pin SOT-23](
    [SN74AHC1G32 Single 2-Input Positive-OR Gate DBV Package 5-Pin SOT-23](
    [TLV760 100-mA, 30-V, Fixed-Output, Linear-Voltage Regulator](

    Now I need to make a circuit board.

    I haven't designed a circuit board in many years.

    Would you please recommend design software that will allow me to work with TI's SOT-23 devices?

    And would you please recommend a vendor who can produce a few circuit boards if given the file generated with the design software?

    Thanks so much for all your help

  • Hello John,

    Thanks for following up. We are glad that you were able to select the parts you needed for your designs.

    Here is a link that says some of the software packages that you can use for PCB export for our parts. (All will support SOT-23 packages)

    There are a number of free PCB design tools as well, such as Altium's CircuitMaker that you could use (i think assuming its for personal use, and not commercial, but we don't specifically endorse any tool).

    For getting boards built, sometimes it depends on the location where you are at. It is likely best to just google search this to see what works for you.

  • Hi Michael,

    Thanks for nudging me toward webench. 

    Emrys mentioned this in his post but I was so busy looking for devices that I never followed up.

    It looks great and there seems to be lots of videos on youtube about how to use it.

    There is even one on how to use webench with Altium's CircuitMaker.

    Really, all I need to do is design a circuit board to hold the TI parts mentioned in the previous post using good design practices.

    If there are any official TI tutorials on webench that you would recommend for beginners I would be grateful to know about them.

    Thanks again for all your help,


  • Hey John,
    It looks like the Webench team has a site with quite a few videos ( ) - you might try looking through those to see if something helps. You can also post directly to the Webench forums to get in touch with those guys if you're having any trouble.