AD9777: Full-Scale Output Current limit

Hi

I am wondering if it is possible to get more than 20mA fullscale output current from the AD9777, without degrading performance.

I see all of the plots in the datasheet are for 20mA.

I am hoping to use this device (or similar) on an ATE board, to interface with a new IQ modulator. The modulator is specified for 20mA, but having the capability to go up to 25mA would be ideal.

This board will then be used in Production Test.

I need the capability to source either a 10MHz sine wave or 10MHz/11MHz dual tone.

The digital on my ATE is limited to 50 MSPS at present, but with a licence add on I can get 100MSPS. Plus my ATE digital generates CMOS/TTL levels. I would require an CMOS->LVDS converter for any of the LVDS DACS. (Not a major issue)

Based on this limitation and having the ability to go greater than 20mA, is there a significant degradation in IMD when sourcing the dual tone mentioned.

The target Output IP3 of the Modulator is ~30dBm

I have looked at other devices, but I want to keep the pcb design as simple as possible and I'd like a DAC, I can get up and running relatively easily.

If you have and comments or other DACS in mind please let me know.

If you need more details, please let me know.

Thanks

Kind Regards,

        Paul.

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  • 0
    •  Analog Employees 
    on Jun 27, 2012 10:22 PM

    The AD9777 has max output current of 21 ma. We have newer parts AD9779 and AD9125 which both support output currents up to 31ma and also show IMD performance curves  at 10ma,20ma and 30ms so you can see the perforamance change with output current. The AD9125 is our newest part with CMOS data interface. If offers the most features smallest package and should be able to support the performance you are looking for.

                                       Best Regards

                                       Tom

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  • 0
    •  Analog Employees 
    on Jun 27, 2012 10:22 PM

    The AD9777 has max output current of 21 ma. We have newer parts AD9779 and AD9125 which both support output currents up to 31ma and also show IMD performance curves  at 10ma,20ma and 30ms so you can see the perforamance change with output current. The AD9125 is our newest part with CMOS data interface. If offers the most features smallest package and should be able to support the performance you are looking for.

                                       Best Regards

                                       Tom

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