Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 48 subscribers
  • Views 216 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.

LM2902: Definintion of short circuit current

Brian Wang0
Expert 5170 points
Part Number: LM2902
Other Parts Discussed in Thread: TINA-TI

Hi team,

In the datasheet of LM2902, I noticed the we have a short-circuit output current ±40mA measured @ Vcc=5V， GND=-5V and Vo=0.

My question is 

1. If we are using single power supply, Vcc=5V GND=0, is the short-circuit current remains the same?

2. When I look at other amps, this SPEC is usually noted @ Vo=Vcc or Vo=GND. Why we are noting Vo=0 here?

3. For LM2902KAVQPWR, is there any embedded short circuit protection? Is it safe for device to work at a shorted condition?

4. Is thermal (Vcc *Ios*thermal resistance) the right way to tell the working range of the device?

 

Thanks，

Brian

LM2902

  • 0
    TI__Guru*** 149776 points

    Hello Brian,

    1) When output wants to go high the current is the same. When output want to go low the current will be close to zero. (Vo=0V)

    2) LM2902 predates those devices, why did they not do it the LM2902 way? Bipolar +/- supplies were more common back then.

    3) For sourcing current, there is circuitry to limit current. It is relatively safe (VCC<15V) but still stressful for the op amp. Shorts to VCC are more harmful. See AMR table and notes in the data sheet.

    4) This equation estimates the self heating temperature. Temperature is a key factor to semiconductor lifetimes.  

    Shorts should be a rare fault condition. It should not be a normal or frequent event.

  • 0 in reply to Ron Michallick
    TI__Expert 5170 points

    Hi Ron,

    Thanks for the reply.

    From my understanding, if the Vo is between V+ and V-  then the short circuit current aligned with the datasheet.

    If V-- is 0, and vo is 0(vo equals to V--) then the sink current would be 0?

    In the datasheet, we also noted the duration of output short circuit to groud is unlimited. How to understand this parameter?

     

    Regards,

    Brian

  • 0 in reply to Brian Wang0
    Guru 140200 points

    Hi Brian,

    that's what the TINA-TI simulation is showing:

    brian_lm2902.TSC

    Kai