AGC loop using AD8318 and ADL5330

Question

I want to design an AGC loop as described in datasheet of the ADL5330. 
 
 I have two questions: 
 1-) AGC loops need a VGA, a detector and a comparator. As can be seen from the datasheet, there is no comparator to be used for AGC loop. 
 Is it only populating ADL5330 and AD8318 enough to construct an AGC loop? 
 
 2-) Bandwidth of the AD8318 is very wide which is from 1MHz to 8GHz. 
 But I want to only measure 20MHz bandwidth around 1.5GHz. 
 Is there a setting for AD8318 to adjust its bandwidth since I do not want to use additional SAW filters?

Bruce_H · Accepted Answer

Hello there, 
 1) Devices such as AD8318 have the word CONTROLLER in the product name. In controller mode, the internal output amplifier driving the VOUT pin DOES NOT connect back to the VSET pin. In this controller configuration, the AD8318 internal output circuitry becomes the integrating error amplifier for the AGC loop. External capacitance on CLPF pin sets the loop integration time constant. 
 2) 
 bugra02 said: Is there a setting for AD8318 to adjust its bandwidth 
 No. But you could use other circuitry besides SAW filter for the filter function: a ceramic cavity resonator, a simple lumped element low-pass, high-pass, or both. Or shorted quarter wave stub.

Electronic Design Services - PartnerZone

Products In This Thread

AGC loop using AD8318 and ADL5330

Top Replies