• Replies 5 replies
  • Subscribers 1426 subscribers
  • Views 618 views
  • Users 0 members are here
Options
Related

AD8009 capacitive load drive capability

Memet

There Folks

I designed an input, output AC Coupled amplifier by AD8009. output ac couple circuit has a 47u capacitor.

are there any issues for ad8009 to working with this cap value as an output ac coupling?

TanQ

Parents
    •  Analog Employees 
    on Dec 3, 2019 8:51 AM

    Hi,

    Can you show your schematic, 47uF seems too large. What will be the next stage after the AD8009? What is your load?

    Regards,
    Goz

  • on Dec 3, 2019 8:14 PM in reply to Gauzz

    Dear Gauzz

    Thank you for the reply.

    the load that I said before is input of AD8302 and its input ac coupled capacitor.

    yes 47u seems too large. I plan to use AD8302 in a wide frequency range from 20Hz to 50Mhz.

    I plane to use AD8009 or AD8007 as last stage buffer of my analog front end circuit before AD8302.

    before AD8009 I have a resistive Attenuator, one AD4817 as a High Speed FET input buffer and a AD8337 as a VGA and then a AD8009/8007 as a buffer between the input circuits and AD8302.

    also my other discussion about AD8067+AD8009 vs AD4817+AD8009 composite amplifier is related to this circuits.

    after these AD8009 buffer, I have another signal path that need to amplify input by 80dB gain and I plan to do it by two composite amp that each has 40dB gain and multiplexed 0dB, 40dB and 80dB by a AD8174 with 0dB gain.

    these high gain stages must be ac coupled in range 20Hz to 50Mhz.

    so it is.

    I highly appreciated to have your kindly recommendation about the circuit.

    PS: the schematic is something like this

Reply
  • on Dec 3, 2019 8:14 PM in reply to Gauzz

    Dear Gauzz

    Thank you for the reply.

    the load that I said before is input of AD8302 and its input ac coupled capacitor.

    yes 47u seems too large. I plan to use AD8302 in a wide frequency range from 20Hz to 50Mhz.

    I plane to use AD8009 or AD8007 as last stage buffer of my analog front end circuit before AD8302.

    before AD8009 I have a resistive Attenuator, one AD4817 as a High Speed FET input buffer and a AD8337 as a VGA and then a AD8009/8007 as a buffer between the input circuits and AD8302.

    also my other discussion about AD8067+AD8009 vs AD4817+AD8009 composite amplifier is related to this circuits.

    after these AD8009 buffer, I have another signal path that need to amplify input by 80dB gain and I plan to do it by two composite amp that each has 40dB gain and multiplexed 0dB, 40dB and 80dB by a AD8174 with 0dB gain.

    these high gain stages must be ac coupled in range 20Hz to 50Mhz.

    so it is.

    I highly appreciated to have your kindly recommendation about the circuit.

    PS: the schematic is something like this

Children
No Data