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I want to get some information about AD9864's Mixer

I want to get some specification about AD9864's mixer.

I have not found in the data sheet specifications of the mixer.

ex) Conversion Loss, Isolation and LO Level

  • Hello,

    The AD9864 includes a section called IF LNA/Mixer with figure 43 showing a simplified schematic.   Note that the active mixer drives a pair of inductors that serves as the "current mode summing junction" of the 1st stage LC resonator of the bandpass sigma delta ADC.  The LNA/Mixer can be viewed as a transconductance block with effective gm of around 10 mA/V.      LO drive level is specified to be 0.3 to 2.0 Vp.p. (page 4).   Reverse isolation is not specified but likely to be high considering active mixer design along with LNA gain stage. 

  • Hello.

    Thank you for your advice.

    But I would like to know the conversion loss of the mixer.

    Have you ever give me a graph of the conversion loss of the mixer?

    If the following conditions, the signal level of the MXOP or MXON?

  • Hello,

    As mentioned in previous email, the conversion gain of the LNA and "active mixer" is 10 mA/V since the output of the mixer is a current that feeds into the summing junction consisting of a feedback DAC and resonator load.  The LO drive level can be anywhere from 0.3 to 2 Vp.p. with the LO port providing an input impedance of 1 kohm (effectively a PIN of -19.5 dBm to -3 dBm).

    The design metric when doing a line-up is the IF Input Clip Point as a function of VGA attenuation since this corresponds to the  max CW level into ADC (allowing for -2 dBFS back-off from ADC full-scale to ensure ADC stability).  Note that 10.7 MHz IF is on the low side of the IF input operating range where one may see degraded noise/spur floor due to digital noise coupling..........may want to also consider 21.4 or 45 MHz if possible.