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LF412: clamp diode ratings

SIDDHARTH MOHAN
Genius 3205 points

Part Number: LF412
Other Parts Discussed in Thread: TL052, TL072

Hi All, 

can anyone please let me know what is the max voltage that can be applied to the inputs of LF412 ? i see that the min voltage that can be applied is VEE. 

also are there any clamp diodes present from each input to the supplies ? if so at what forward voltage will they conduct 10ma input current?

thanks 

  • 0
    Guru 140200 points

    Hi Siddharth,

    almost the same is valid what I have said here:

    e2e.ti.com/.../683794

    There are no clamp diodes in the LF412 at the inputs. Additionally be very careful: The input voltage must never go below the negative supply! Otherwise latch-up can occur and destroy the LF412. This chip does not even withstand the least negative voltage. To work with this chip a diode clamp at the input is obligatory, when connecting the inputs to signals coming from outside of the circuit. And it's wise to have a voltage divider between the clamp and the input of LF412.

    The TL072 and TL052 are much more robust in this subject. The inputs can easily be protected by a current limiting resistor.

    Kai

  • 0 in reply to kai klaas69
    Genius 3205 points
    thanks for the reply Kai, the datasheet clears that the input shouldn't go below the VEE but what about the positive side, what is the max voltage that the part can sustain?
  • 0 in reply to SIDDHARTH MOHAN
    TI__Guru**** 174826 points
    Siddharth,

    Inputs can go up to +30V above Vee (pin4).
    There is no diode from input to to pin 8; no current will flow.