If the input RF power exceeded the absolute max input power 2.5dBm, what kind of failure would happen? Power failure of voltage failure?
The maximum single ended input signal level for Rx LNA is +2.5dBm (wrt 50ohms). Differentially it is +5.5dBm (wrt 100ohms). It is an absolute maximum rating and if exceeded can result in permanent damage or compromised long term reliability.
What kind of failure would be caused by the violation of absolute max rating of input RF power? Power failure or voltage failure?
Testing was performed using a source delivering power measured in dBm units. It has not been investigated whether failures are due to power or voltage. It is recommended to provide fast acting protection at Rx inputs to limit signal amplitude to following levels: +2.5dBm (wrt 50ohms) single ended or +5.5dBm (wrt 100ohms) differential.
The above ADI post from "tlili" states: " It is recommended to provide fast acting protection at Rx inputs to limit signal amplitude to following levels: +2.5dBm (at 50ohms) single ended or +5.5dBm (at 100ohms) differential." After looking through ADI's responses to various questions about max Rx input levels and protection, this is the only response I see that indicates that even a slight overdrive might not damage the input circuits instantaneously.
This is good news because it is very difficult to prevent all input transients that might exceed 0.42Vpk (+2.5dBm peak). If the chip could be instantaneously damaged, then it would be useless in a real RF environment since input protection circuits usually have some small delay. Can ADI give us any guidance at all on a rough order of magnitude of overdrive time it might take to damage the input (nanoseconds, microseconds, milliseconds, seconds, etc.)? I know this damage time is probably dependent on the amount of overdrive, so let's say it's briefly around +20dBm or so.
This is an important issue for ADI to test or estimate and provide some customer guidance. If this damage time is instantaneous or too short, then protection circuits are impossible, and the chip is useless in most real-world environments. Thanks for your help in this important matter.
I cannot provide anything more than what is in post 3.
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