Using the pre amp of AD8336 as a differential to single ended amplifier

hi Folks

according to AD8336 datasheet, it is a single-ended input and output VGA, but my question is:

1. Is it possible to use its pre amplifier as a differential amplifier to changing a differential input signal to a singled-ended one pass to its VGA part? actually I want to use its pre-amp as a differential to single ended-part of a discrete instrumentation amplifier.

2. the AD8336 datasheet just offered two resistors for 12dB(x4) gain of biasing the pre amp, and said nothing about 26dB(x20) biasing resistor. which resistors are suitable for 26dB gain?

3. are there any app notes about nulling AD8336 offset voltage in high gain? or Do you have any solutions/circuits for doing it?

I highly appreciated to read your comments


Parents Reply
  • Hi Memet,

    why did you offer this? you prefer this rather than resistive pi type attenuator?

    No, this does not apply to the input part. This is just one of the possible ways to nulling the offset that I invented and suggested. It does not have any special advantages and looks sophisticated.

    The integrator method can be implemented in this way

    I want to warn you that this method, although very attractive, will give you a headache when implemented. You will need to use high-ohm resistors and large value capacitors to obtain a large time constant that will not affect the bandwidth. Do not rush to apply it. Stick to the decoupling capacitors first.

    how can I coupling the output of AD8336s to AD8302 via ADG1419?
    is the difference topology of the AD8336's pre-amp and its biasing ok or not?

    What's bothering you here? Please explain what you mean by biasing?

    still I can keep that difference amplifier topology for  pre-amp of AD8336. does it works?

    If you can somehow connect the signal source to the amplifier with a symmetrical transmission line, this will be justified. More precisely, the use of INA here will be justified.

    still AD8066 or single version of it AD8065 is suitable for first stage before AD8336?

    I do not know any special advantages of using a dual amplifier instead of two single ones, except for saving space on the PCB and the price.

    is using of AD8066 suitable for this purpose or not?

    Since the input circuits are fairly low-impedance, a bipolar op-amp can give the main advantage here-a lower noise voltage. This is a feature of bipolar op-amps.