ADL5511 in an AGC loop application

Document created by analog-archivist Employee on Feb 23, 2016
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A customer is using the ADL5511 in an AGC loop application, by applying a sine
wave at different power levels using a signal generator and using the Vrms
output pin to measure the output.  They have a 75 Ohm resistor connected
between pin 2 (RFIN) and ground.  The circuit is not behaving as it should.


The RF input needs to be AC-coupled and the 75 Ohm resistor to ground should
not be  connected directly to pin 2 (RFIN). They may be pulling down the bias
level on the RF input. The input frequency will determine whether they need
caps on FLT2 and FLT.