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Required Details of LM2904 OP-AMP.

Girish BG
Prodigy 30 points
Other Parts Discussed in Thread: LM2904, LMV358

Hi, 

Please provide the output voltage (VOH) Min,  TYP & MAX(@ V+ = 5V). Currently in the datasheet the value is been available for V+ = 26V as shown in below figure.
    
  
  

Best regards / Mit freundlichen Grüßen

Girish BG
  
  
  
  
  
  
  
 
 
 


  • 0
    TI__Intellectual 1190 points

    Please refer to the latest datasheet online --> http://www.ti.com/lit/ds/symlink/lm158.pdf

    You can use Vcc - 1.5V for the min.

  • 0 in reply to Andrew Leverette
    Prodigy 30 points

    Hi Andrew,


    Thanks for the response.

    Here i have a situation that the output signal of my op-amp (LM2904) will be connected to the GPIO of Micro-Controller.

    Consider a my minimum output voltage is (VCC-1.5V) = 3.3V - 1.5V = 1.8V.(op amp output)


    And the minimum voltage to detect as high from the Micro-Controller is 0.65 x VCC = 0.65 x 3.3 = 2.145V.(Micro-Controller Input)

    Please let me know at which condition my op amp will be at minimum level of  VCC - 1.5V.

    Regards,

    Girish BG

  • 0 in reply to Girish BG
    TI__Guru**** 150296 points
    Girish,

    VCC - 1.5V as the worst case applies only if load to ground is 10k ohms or greater and temperature is 25C.
    For every 1C decrease in temperature, VOH will drop by 4mV as the device goes below 25C.

    LMV358 is a better solution because it has rail to rail output.

    Nevertheless you may add a pull up resistor to LM2904 output. It should provide 100uA at 2.145V to certainly over power the weak sink driver in LM2904. R pull up < 11.5k

    Now VOH will be fine and the problem moves to VOL. VOL will be about 0.7V at 25C and increase 2mV for every 1C decrease in temperature. At -40C, VOL will be about 0.83V which is less than 33% of 3.3V.