NI PCI-6723 output buffer

[ASIM_BHATTI]

Hi all

          I have 32  power amplifiers for driving transducers. These power amplifiers need some sine wave as an input signal. Each poweramplifier input stage draws about 5mA to 10mA.Kindly guide me if i want to use NI PCI-6723 DAC for 32 sine wave generations, do i need some isolation stage b/w PCI-6723 DAC and power amplifiers for DAC protection or PCI-6723 DAC has some builtin output isolation stage?

Second question is that PCI-6723 DAC has output current limit of 5mA/channel. Can i use some buffer stage b/w DAC and power amplifierS to provide atleast 10mA current/channel? Simply stated can i enhance output current capability of PCI-6723 DAC from 5mA/channel to 10mA/channel to drive my power amplifiers?

THANKS

[Steve_B]

Hi Asim,

You are correct that you will need to have an amplifier stage between the 6723 output and the power amplifiers you are working with if you need up to 10mA per channel. The board is only able to supply 5mA per channel so you will need to take that into consideration when choosing your amplifiers. Another option would be changing the power amplifiers with another part that has a smaller current draw (<5mA) if that is possible.

[ASIM_BHATTI]

Hello Steve

                Thanks for reply. Kindly tell me if somehow i modify input stage of my poweramplifier so that i draw less than 5mA cuurent, do i still need some buffer or isolation b/w NI 6723 and power amplifier for 6723 protection?Or can i directly drive poweamp from NI 6723?

Thanks

[Steve_B]

Hi Asim,

If you are able to get around the 5mA current limit for each channel, you will still need to consider that each AO channel will be referenced to the same ground. This could potentially be a problem if you cannot reference each of your power amplifiers to the same ground. Another consideration would be the maximum working voltages for the card:
Ch-Earth +/-11V

Ch-Ch +/- 22V

If you are able to work around these considerations you should be fine without a buffer/isolation stage between the 6723 and your amplifiers.

Steve