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LM211: Worst case ICC+ at high temp

Kazuki Itoh
Genius 10045 points
Part Number: LM211
Other Parts Discussed in Thread: LM111-N, LM111

Hi team,

Could you please provide the worst case maximum ICC+ value at TA=85degC and VCC=5V (single supply) of LM211?

My customer is trying to update the power supply and estimating the current consumption.

Best regards,

Itoh

  • +1
    TI__Guru 54076 points

    Hello Kazuki,

    This is an old (50+ years) device and we have limited data on it.

    From the LM111-N datasheet:

    Do note that the supply current is higher at low temperatures - which is common for bipolar devices - so they should actually concentrate on the low temperature for the max current.

    Since we do not have data for 85C and 5V, we can extrapolate from the above curves.

    The change in supply current between 5V and 30V is fairly linear, so we can extrapolate the 5V current from the 30V curve.

    The change from 5V to 30V is 3.5mA to 5mA, or 0.7.

    The current at 30V and  85C is about 4.1mA, so 4.1mA * 0.7 = 2.87mA

    The current at 30V and -40C is about 7mA, so 7mA * 0.7 = 4.9mA.

     Add the typical variance of about +15%, so about 5.6mA.

    These numbers are for design guidance only.

    Is there a particular reason they are using the LM211? There are much better alternatives at 5V supplies if quiescent current is an issue.

  • 0 in reply to Paul Grohe
    TI__Genius 10045 points

    Hi Paul-san,

    Thank you for your support.

    Actually, my customer wants to check LM211DR (TI part), not LM211-N (National part).

    In LM211 datasheet, the figure 22 and 23 are not described.

    Is your calculation and result directly applicable to LM211 as well?

    I'm recommending the customer to switch to newer part as you mentioned.

    Regards,

    Itoh

  • +1 in reply to Kazuki Itoh
    TI__Guru 54076 points

    Hello Itoh-san,

    The TI LM211 is a second-source of the National LM211 - so they are fairly close. The National may be is worst case as it is an older (but similar) process.

    Can you share their application? We can take it internally to save customer confidentiality.

    The LM111 family was designed in the split supply, ±15V days and is not ideal for single 5V supply. We have much better options now.