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LM20: Failure modes

ttd
Mastermind 7660 points
Part Number: LM20

Dear Technical Support Team,

Do you have the information of failure mode? 

When failure mode occurs ,  what does LM20 output(High or Low or HIz or open)? 

Best Regards,

ttd

  • 0
    TI__Expert 4875 points

    Hello,

    I will have to check with our design engineers on this question. I will get back with you as soon as I get a response.

    Thank you and regards,

    Audrey

  • 0
    TI__Expert 4875 points
    Hello,

    If you are referring to the failure in which power is no longer supplied to the IC, the expected voltage at the gate of the CMOS will be 0 V. This means that the output should be high-Z. However, it is not guaranteed that the gate will be 0 V, due to possible parasitics in the IC, and so it may be floating. This could mean the NMOS is on and the output is tied to ground.

    Hope that this helps.

    Audrey
  • 0 in reply to Audrey Dearien7
    Mastermind 7660 points

    Hi Audrey,

    LM20 is analog output device below figure.

    Does it have cmos gate logic on output?

    If it is yes, could you show the structure of it? 

    ■Datasheet

    Shutdown capability for the LM20 is intrinsic because its inherent low power consumption allows it to be powered directly from the output of many logic gates or does not necessitate shutdown.

    Best Regards,

    ttd

  • 0 in reply to ttd
    TI__Expert 4875 points

    Hi,

    According to the datasheet, the LM20 is an analog CMOS output device. Since this is a dated part, I do not have the information on-hand about the structure of the output. I am consulting our design team to see if they have more information on this.

    Thank you,

    Audrey

  • 0 in reply to Audrey Dearien7
    TI__Expert 4875 points
    Hello ttd,

    As I posted before, I cannot answer with certainty, since this device was adopted from National. However, from looking at the source/sink current capability, I can imagine it is most likely a emitter-follower type structure because of the low sink current as compared to architectures using the push-pull structure where the sink current is much higher.

    Hope this helps.

    Regards,
    Audrey