• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 46 subscribers
  • Views 306 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

LM193: regarding operational conditions

Yusuke Kawate
Prodigy 150 points
Part Number: LM193
Other Parts Discussed in Thread: LM339

Dear experts,

 Would you please let us know that below condtions are OK or NG for suitable use of LM193 ?

 Condition1

   - Input(IN+) : 0V ~ 12.0V

   - Input(IN-) :0V ~ 2.5V

Condition2

   - Input(IN+) : 1V ~ 16V

   - Input(IN-) : 0V ~ 2.5V

 

Are these conditions no problem ?  

Our customer think these conditions are followable precaution of LM193 Datasheet (page 4 _ 6.1 Absolute Maximum Ratings).

 

Thank you in advance.

Best regards,

Yusuke Kawate

TED

  • 0
    TI__Guru 58606 points

    Hello Yusuke,

    Absolute maximum ratings are not functional ratings. They just describe voltages that can be applied without damaging the device. Proper operation is not assured. You must stay within the limits in the Electrical Characteristics tables (table 6.1).

    What is the supply voltage for the comparator?

    All input voltages must be at least 2V below the supply voltage (Vcc - 2V).

    From your conditions above, the minimum supply voltage should be 18V (16V + 2V).

  • 0 in reply to Paul Grohe
    Prodigy 150 points

    Hello Paul-san,

    Thank you very much for your kind reply.   And I apologize to you my miss discription and pasting wrong page.

    As your mention, they mind operating precaution - Datasheet Page8. 6.10 Electrical Characteristics  precaution(2).

    And I heard Vcc is 12.0V.

    Collect my discription below.  Are these no problem for suitable operation ?

     Condition1

       - Vcc : 12.0V

       - Input(IN+) : 0V ~ 12.0V

       - Input(IN-) :0V ~ 2.5V

    Condition2

       - Vcc : 12.0V

       - Input(IN+) : 1V ~ 16V

       - Input(IN-) : 0V ~ 2.5V

    Our customer think these conditions are followable precaution of LM193 Datasheet (page 8 _ 6.10 Electrical Characteristics  precaution(2)).

    Thank you,

    Best regards,

    Yusuke Kawate

    TED

  • 0 in reply to Yusuke Kawate
    TI__Guru 58606 points

    Hello Yusuke,

    Technically, it violates the specified operating conditions. For a 12V supply, the maximum input voltage is 10V.

    However, the LM193 family has a two features that will allow these conditions.

    1. The inputs can go up to 36V regardless of supply voltage.

    2. As long as one input is still within legal range (2.5V), the output will be correct even when the other input exceeds the limit.

    So from their conditions, the output will be correct, even at 16V. This is expected behavior, but not guaranteed as they are operating outside specified operating conditions. It is up to the customer if they wish to operate outside specified range. 

    Please see section 2.5 and 2.8 of the LM339 family application note:

     Application Design Guidelines for LM339, LM393, TL331 Family Comparators

    In short, yes, it will work but some specifications, like prop delay and bias current, will vary. TI always recommends operating within the specified limits (Vcc-2).