OP2177 protection diode

Hello

We will use OP2177.

In absolute maximum rate of the datasheet, input range is -Vs ~+Vs.

The datasheet of opamp usually include  the description of  power supply +- 0.3V at input

Does OP2177 include  a protection diode at input stage ?

If not so, we will add external diode.

Please let me know your advice.

Regards,

Parents
  • 0
    •  Analog Employees 
    on Nov 27, 2017 4:34 PM over 3 years ago

    Hi Terumasa, 

    There are no input clamping diodes on the OP2177. If inputs go beyond the supplies, it is recommended that the current be limited to 5mA. Please see the Input Overvoltage Protection section on the datasheet.

    Also, what design stage are you in and what is your application. I would also suggest you look at the ADA4177-2 if it fits your requirement. It has integrated overvoltage protection, higher bandwidth, lower noise, and low bias current. 

    Thanks, 
    Kris

  • Hello Kris,

    Into section input overvoltage protection it is written :

    The OPx177 has internal protective circuitry that allows voltages as high as 2.5 V beyond the supplies to be applied at the input of either terminal without any harmful effects.

    What kind of protection is used ?

    Do you have an internal schematic to share with us ?

    I am loonking for internal path from IN to VS.

    There is a PCN 18_0060.

    Does it impact the protection circuitry?

    Best regards,

    Areski

  • Hi Areski,

    You can use the OP177 datasheet, which has an internal circuit. These amps are related

    Regards,

    Kirill

  • Hi Kirill,

    There is a PCN 18_0060.

    Is it possible to have more details regarding circuitry modification ?

    PCN -> This includes the transistor layout, rerouting of circuitry

    Regards,

  • Hi Areski,

    My initial assumption was that this amplifier belongs to the OP07 family. And we should expect similar input protection circuitry. But you can't say anything unambiguous, because there is no uniformity in the data sheets. I believe that OPX177 uses back-to-back diodes and two resistors in series with inputs, as in OP07/ 77/177.

    But the specification for the absolute maximum differential input voltage depends on the supply voltage, which is not typical for older OP07 family amplifiers. This means that the protection circuit has changed, and only ADI specialists can say something specific

    By the way, why are you interested in the internal protection circuit?

    Regards,

    Kirill

Reply
  • Hi Areski,

    My initial assumption was that this amplifier belongs to the OP07 family. And we should expect similar input protection circuitry. But you can't say anything unambiguous, because there is no uniformity in the data sheets. I believe that OPX177 uses back-to-back diodes and two resistors in series with inputs, as in OP07/ 77/177.

    But the specification for the absolute maximum differential input voltage depends on the supply voltage, which is not typical for older OP07 family amplifiers. This means that the protection circuit has changed, and only ADI specialists can say something specific

    By the way, why are you interested in the internal protection circuit?

    Regards,

    Kirill

Children
No Data