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LMV331: power on rest

Fred Cheng
Expert 4660 points
Part Number: LMV331
Other Parts Discussed in Thread: TLV9032, TLV7011, TLV7021

Hi team,

what will happen to the output  when the power on VCC is not yet 2.5V ?

is there any reset circuit inside that can prevent  this unstable phase?

Regards,

Fred

  • 0
    TI__Mastermind 23425 points

    Fred

    Thanks for your post.  Unfortunately, devices such as the LMV331 do not include a power on reset circuit.  If that is required, may I suggest our TLV7011 (push pull) or TLV7021 (open drain) family of comparators which has a POR circuit.  We just do not have enough characterization data on the LMV331 in order to provide a warranted startup condition.  Most likely the LMV331 will start high Z at the output but as it reaches the recommended operating range, it is possible that some unpredictable output conditions could occur.  If the TLV7011/21 is not fast enough, we will be releasing a single channel variant of the TLV9032/22 family soon and this will also include POR circuit.

    Chuck

  • 0 in reply to Chuck Sins
    TI__Expert 4660 points

    Hi Sins,

    may I know why POR can prevent this?

    is there a diagram or picture that can explain this?

    thanks

  • 0 in reply to Fred Cheng
    TI__Mastermind 23425 points

    Fred

    sorry for the delay.  I am not exactly sure what you are looking for but essentially a POR circuit holds the output of the comparator in a known state until the supply reaches the recommended operating voltage.  Just think of it as a comparator within the comparator that monitors VCC.  When the VCC is below the operating voltage, it holds the output in a known state.  Once VCC reaches the operating voltage range, the POR circuit relinquishes control of the output and now the output tracks the input of the comparator.

    Chuck