• AD8646: Overvoltage

    How should I protect from Overvoltage?


    In general we suggest you add external Schottky diodes and current limiting
    resistor to any input which is likely to exceed the abs max ratings. Note the
    diodes need to be mounted physically close…
  • AD8646 Spice model


    Our customer simulate AD8646 with OrCad.

    The schematic is voltage follower.

    The result is strange?? The gain waveform turns the other way from 150MHz.

    Is this the AD8646 performance or spice model bug or wrong simulation?

    Should we ignore…

  • Latch up AD8646


    i am using AD8646 for voltage follower as illustrated in following schematic. the output of AD8646 shall be connected to 12Bit ADC for voltage measurement UDC (range 0 to 820V). The supply of AD8646 is V2 (4,5V), which can be manually turned off…

  • AD8646 slew rate variation.


    Customer would like to know how much variation slew rate AD8646 has. (by Process/Temperature.)

    in the data sheet, typ=11V/usec @RL=2kohm. 

    They would like to know slower case because they are considering to use AD8646 high speed application and Vs…

  • Replacing LMV84x by AD8646/8648 ?


    We are now studying to replace LMV84x on existing system by AD8646 or AD8648, then having questions as follows.

    1) Absolute Maximum Ratings of input voltage at AD8646/8648 is defined as "GND to Vsy".

      I could not find any clear definition…

  • AD8646 Maximum Output Swing vs. Frequency


    We discovered a problem in a data sheet of AD8646.


    Figure 39 "Maximum Output Swing vs. Frequency" of Page12.

    In this graph, center frequency is 1kHz…

  • What is the current noise density of the AD8646/7/8?

    The data sheet says "featuring... low current noise" and then never says what it is. Also, "featuring... low input voltage" should probably read "featuring... low input voltage noise." 

  • RE: Having doubt in layout@CN0326: Isolated Low Power pH Monitor with Temperature Compensation

    Hi Alf,

    You could look at using something like the AD8646.  The specs are fairly similar, but it is higher quiescent current, meaning it wont be as low power for the entire solution.  It does come in a SOIC package.


  • RE: ADA4851-1 maximum value of Input Offset Voltage Drift.

    Hi JinoL-san,

    Thank you for your reply.

    The situation has been changed. customer is considering to use other device "AD8646" for their application now.

    So could you close this question?

    For your information, their application is low side…

  • RE: AD8618 supply decoupling



      What does TRRS mean??

      What is your highest signal frequency?

      Depending on whether you need to go to DC or not and can AC couple, you could use op amps

    that have millivolts of offset, rather than <100 uV which drives up the price.