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modeling differential passive filter in LTSpice

Category: Hardware
Product Number: AD8138

I'm trying to model a discrete component filter being driven by an AD8138, through the filter, and into an LTC2153-14 ADC. I don't have those active components in the sim, just the discrete components, along with their parasitics. While the filter shape is what I expect, it peaks at greater than 0dB no matter how I try to model it, and that is nonsensical. Is there a recommended way to drive a circuit like this differentially and then retrieve the output, also differentially?PN8303_BPF.asc

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  • Hi Earl,

    L4 was an error and we are considering removing it. How can a passive filter provide gain boost above 0dB? I understand that the amplitude is actually dBV, but with unity input it should come out in the wash. Is this performance real, or am I missing a gain factor in the use ot the voltage-dependent voltage source? A passive circuit with gain above 0dB is nonsensical, making me have difficulty believing the results. Any thoughts?

    Mark

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