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ADA4932-1 minimum gain

Hello,

The ADA4932-1 datasheet states "Can be used with gains less than 1". How much less than 1 while remaining stable? Would a gain of 1/3 be ok for stability? I'm planning 1500 = RF, 500 = RG. Datasheet Figure shows very modest peaking for Gain = 1. 

Thank you,

Lucas 

  • Hi Lucas,

    Values should be fine for you, may I know what frequency are you operating at? Remember that you are using noise gain for stability, so at 1/3 gain your amplifier sees a 1.333 noise gain. Seeing the open-loop plot there's enough phase margin for you.

    -Goz

  • Thank you, Goz. 

    The ADA4932 is driving the 5 MSPS AD7960/1 (connected by cables). The plan is to run the input sampling bandwidth of the AD7960/1 at 9 MHz. From the datasheet: "The bandwidth of the input sampling network is set to narrow (9 MHz)."

    I'm OK with the increase in noise gain since my upstream electronics dominate the noise budget. 

    Let me know if you see any concerns here. 

    Thanks, 

    Lucas