• State Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 1 answer
  • Subscribers 50 subscribers
  • Views 217 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TLV9004: Output swing

Zeming Kong
Expert 3515 points
Part Number: TLV9004
Other Parts Discussed in Thread: TLV274, LM7705

Hi team,

My customer is evaluating TLV9004 to replace TLV274. And he needs to confirm the output swing.

The typ. value is 10mV and max. value is 20mV. Will all 4 amps tend to be up to max. value or swing around typ. value or just vary randomly?

Best,

Zeming

  • 0
    Guru 244360 points

    Manufacturing variations will make the the actual output swing vary around the typical value. Temperature effects are more consistent.

    But the four outputs of any single device will behave pretty much the same.

  • Former Member
    0 Former Member

    Hi Zeming,

    I would agree with Clemens' assessment.

    Each amp will vary on its own near the typical value.  Based on other conditions, such as loading, the maximum output swing will change.  Also, note that temperature can have an effect on output swing.  So, if you are using the maximum output current of all four amps at once, you may generate significant heat which could adjust the swing of a channel.

    Regards,
    Daniel

  • 0 in reply to Former Member
    TI__Expert 3515 points

    Thanks a lot for your comments, Clemens and Daniel.

    Understood that the amps will behave the same when in the same operating conditions. 

    Actually, TLV9004 is used to design a amplifying circuit. Could you tell me, if all inputs are 0V, how much output error would be generated by output swing? 

    Do we have data to show the output swing when input=0V?

    Best,

    Zeming

  • 0 in reply to Zeming Kong
    Guru 140200 points

    Hi Zeming,

    can you please post a schematic?

    Kai

  • Former Member
    0 Former Member in reply to Zeming Kong

    Hi Zeming,

    There will be some variation across process for each channel.  Each channel will not provide exactly the same output voltage, but similar.

    The output swing will depend on various factors, such as the supply voltages and load.  Can you share your supply voltages and the reference voltage for your load?  If your load is tied to GND in a single-supply system as described here, then you will actually get very close to 0V at the output.

    On the other hand, if your load is tied to mid-supply away from the supply voltages, then the Vout vs Iout curve in the data sheet will be helpful. Note that the one for the TLV900x data sheet shows the curves for a voltage supply of +/-2.75V.

     

    Regards,
    Daniel

  • 0 in reply to Former Member
    TI__Expert 3515 points

    Hi Kai and Daniel,

    Thanks for your explanation!

    This circuit is something like below, two amps of TLV9004 is used as buffer at the 1st stage, and 1 amp is used as differential amplification at the 2nd stage.

    The customer is worrying about the output swing of 1st stage may be amplified at the 2nd stage, it can cause a big output error. According to Daniel's comment, I understood it should not be a problem.

    Best,

    Zeming

  • Former Member
    0 Former Member in reply to Zeming Kong

    Hi Zeming,

    Do you know what the supply voltage is?  Is this single supply or dual supply?

    If you could provide a schematic, that would help a lot.  For example, if this is a discrete instrumentation amplifier with a single-supply, then there could be non-trivial errors.

    Regards,
    Daniel

  • 0 in reply to Former Member
    TI__Expert 3515 points

    Hi Daniel,

    I will send you the schematic via email.

    Best,

    Zeming

  • 0 in reply to Zeming Kong
    Guru 140200 points

    Hi Zeming,

    keep in mind that the performance of any OPAmp degrades when the output voltage of OPAmp goes all the way to the supply rails. Here you see the open loop gain specification of TLV9004:

    Going closer to the supply voltage rails will make the OPAmp leave its linear range. A good remedy is to use the LM7705 then.

    Kai

  • Former Member
    0 Former Member in reply to Zeming Kong

    Hi Zeming,

    Thank you for sharing your schematic.  I have taken a look and responded via email.

    As explained in my email, a good option to get better accuracy is Kai's suggestion of using the LM7705.

    Regards,
    Daniel

  • 0 in reply to Former Member
    TI__Expert 3515 points

    Hi Daniel and Kai,

    Appreciate your helpful comments!

    I think you have made these points clear.

    Thank you very much for your support!

    Best,

    Zeming