I'm using the ADL5205 for a new design.
I have a doubt regarding the Maximum Input Swing of the ADL5205. While in page 3 of the datasheet specifies that the Maximum Input Swing is 8Vpp, in the absolute maximum ratings of page 6, the datasheet states that the Differential Input Voltage ((VINx+) − (VINx−)) is +-1V. Both informations seem contradictory. ¿What is the true maximum input swing?
My concern is about the maximum input level that the device can tolerate without damage (it doesn't matter if it is in linear operation or saturated) for the whole range of gain codes.
Thank you. Joan Ramon
The “Maximum Input Swing” of 8 Vpp on page 3 is for the lowest gain setting of -9 dB. Then as the gain is increased, the Maximum Input Swing has to be reduced correspondingly to maintain the same maximum output swing.
As for the “Differential Input Voltage” in the Absolute Maximum Ratings table on page 6, that takes effect starting around 14 dB of gain and up. At that point, there’s no more resistive attenuation on the input, so whatever signal is presented on the pins that will directly go on an input ESD protection circuit, which is the reason the input signal swing has to be limited.
do I have to understand the Absolute Maximum Ratings table w.r.t. "Input Voltage (VINx+ ,VINx−) −0.5 V to +3.1 V" similar?
In other words: Is the rating relaxed for gain settings <14dB?
In my application I'm going to drive the ADL5205 by an ADL5391ACPZ at a close to 0dB gain setting. The ADL5391 output can be up to 3.5V (single ended) or even a bit more. Both devices will be powered by 5V.
I'm sorry, it took a while, but I had to check with the designer of the part to be sure. Good news is the part should very likely have no issues with 3.5 V!
thank you for the good news.
As a final note, please keep in mind though that driving the amp that high will technically violate the datasheet values, so ADI will not recommend or support such a use case. But, fact is, ADI tends to be very conservative when setting limitations, and many parts were shown to work just fine well outside the datasheet ratings - without official approval or support of course.