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Help for selecting amplifier

Laszlo Garab
Intellectual 965 points

Other Parts Discussed in Thread: TINA-TI, TLV9062

Hello,

I am developing a battery-operated VoltMeter and looking for amplifier for it. There are many pros and cons on given amplifiers in the selection guide, so it seems better to ask for more experienced people for suggestions.

- The design use four opamp. They can be in 1amp/package or 4 amp/package, space is not a constrain, but PDIP package is preferable.

- In the design I use them in inverting and defference amplifier configuration

- Supply is two AA cell

- Low frequency application

- Price is a medium preference

I am looking for hearing from you about device or suggestions.

Reagard,

Laszlo 

  • 0
    Guru 140200 points

    Hi Laszlo,

    I think a low input offset voltage is important, a low supply current, RRIO capability (RRIO = input output rail to rail) and a low minimum supply voltage. This should narrow your search:

    Or with lower minimum supply voltage:

    Can you show a schematic?

    Kai

  • Former Member
    0 Former Member

    Hello Laszlo,

    You can use Kai's suggestions and the provided links to filter for parts.  Please let me know if the tool is not intuitive in any way or if you need any help in understanding how it works.

    I would add something else here.  The advantage to using 4 different units for your 4 different channels is that you will have more variety to pick from and you may choose different devices for different portions of the circuit.  This is also true if you pick 2 devices that each have 2 channels per unit.

    However, picking one device with 4 channels/unit will typically give you the most cost-effective solution for that part.  In other words, it's cheaper to buy 4 channels in a single part than to buy 4 single-channel parts (assuming it is the same device).

    Regards,

    Daniel

  • 0 in reply to kai klaas69
    Intellectual 965 points

    Hai Kai,

    I had identified as key parameters RRIO and low supply voltage. Thank you for calling my attention to low offset. However, I can calibrate the circuit high offset 2-5 mV can cause a problem. Additionally, my attention come to high CMRR because of the inverting topology.

    PDIP package would be preferable.

    On the evening I have to run new searches taking consideration this point of views.

    Thanks for the points,

    Laszlo

    PS: I can draw a shematic with Tina-TI but I have to find the amplifiers to draw with

  • 0 in reply to Former Member
    Intellectual 965 points

    Hello Daniel,

    thank you for the idea of not using same amplifier on the same position of the circuit. This adds some more possibilities to take into consideration.

    Regards,

    Laszlo

  • Former Member
    0 Former Member in reply to Laszlo Garab

    Hello Laszlo,

    Happy to help.  Two more things I'd like to add.

    1.  You can select the package type in the tool and search for PDIP devices.

    2.  When you select an amplifier and wish to put it into TINA, simply find the product page for the device online.  Then, click on "Design and Development" and finally "Design tools & simulation."  You will be directed to the location of the SPICE model(s) for the device.  The vast majority of op amps will have a SPICE model.  See below for an example for the TLV9062.  Please let us know if you need any further help.

    Regards,

    Daniel