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LM2904: About typical output voltage at Vcc=+12V

Tao_2199
Genius 5740 points
Part Number: LM2904

Hello,

 

Regarding to output voltage on LM2904, my customer is asking some question.

 

When Vcc=+12V,how many typical output voltage is it?

Do you have something plots?

 

By the way, I have tried WEBENCH from LM2904 page but I couldn't continue to simulation with error message.

 (Please refer below.)

 


 

I'm not sure why error message is described. Is there anything wrong point?

 

Regards,

Tao2199

  • 0
    TI__Guru**** 152796 points
    Tao2199,

    Figures 8 and 9 in LM2904 data sheet show the VOH and VOL cuves.
    The error is caused by the output trying to be 0V while sinking 667uA (from the output load).
    The VOL curve shows that output can't be zero.
    Getting up to 8.7V while sourcing 300uA is fine.
  • 0 in reply to Ron Michallick
    Genius 5740 points

    Hello Ronald,

    Thank you for reply.
    I will inform answer to my customer.


    (Additional question)
    ･They are asking about VOH voltage (minimum/typical) at Vcc=12V, RL=10kohm, "full range temperature(–40 to 125 C)" .
    Do you have something data for above conditions?

    Regards,
    Tao2199

  • 0 in reply to Tao_2199
    TI__Guru**** 152796 points

    Tao2199,

    This VOH minimum spec can be translated down to 12V. Normal VCC is 26V, so 23V is 3V loss at 23V/10k = 2.3mA.

    For 12V, VOH worst case limit will be 12V-3V = 9V at 2.3mA which is 3.9 k ohms.

    So VOH minimum is 9V with 3.9k load.

    This VOH typical pec can be translated down to 12V. Normal VCC is 26V, so 24V is 2V loss at 24V/10k = 2.4mA.

    For 12V, VOH worst case limit will be 12V-2V = 10V at 2.4mA which is 4.2 k ohms.

    So VOH typical is 10V with 4.2k load.

    With a 12V and a 10k load, VOH will be slightly higher.

  • 0 in reply to Ron Michallick
    Genius 5740 points

    Hello Ronald,

     

    Thank you for reply.

    My customer is asking additional question.

    (1) VOH typical is 10V with 4.2k load.( from your previous answer.)

    In this case, what temperature range did you measure?

    At 25℃? or at Full range(–40 to 125℃)?

    If that data is at 25℃, do you have a data at full range temperature?

     

    (2) VoH(min) is 10.5V. ( RL ≧ 10 kΩ, TA=25℃, Vcc=12V) (from datasheet page 6)

    In this case, do you have a data at full range temperature(–40 to 125℃)?

     

    Regards,

    Tao2199

  • 0 in reply to Tao_2199
    TI__Guru**** 152796 points

    ao,

    Typical values are alway taken at 25C.
    I did not take any new data, I simply interpolated the data sheet characteristics table to a 12V supply.

    I no not have 12V data.

    Here is 5V sample data (60 samples)

         Voh2        10k      5V           
  LotID.Tmp           Mean     StdDev       Mean-3s     LowRead      HiRead     Mean+3s  
-----------------+-------------------------------------------------------------------------
NOMINAL_N.-40C|     3.520V    16.346mV      3.471V      3.492V      3.555V      3.569V  
NOMINAL_N.0C  |     3.690V    18.424mV      3.634V      3.652V      3.727V      3.745V  
NOMINAL_N.25C |     3.793V    19.760mV      3.733V      3.762V      3.836V      3.852V  
NOMINAL_N.70C |     3.968V    21.099mV      3.904V      3.934V      3.996V      4.031V  
NOMINAL_N.85C |     4.020V    20.478mV      3.958V      3.980V      4.055V      4.081V  
NOMINAL_N.125 |     4.172V    23.515mV      4.101V      4.121V      4.211V      4.242V