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AD8334 Production
The AD8334 is an ultralow noise, quad channel linear-in-dB variable gain amplifier (VGA). Although optimized for ultrasound systems, it may be used as...
Datasheet
AD8334 on Analog.com

AD8331 Production
The AD8331 is a single channel, ultralow noise, linear-in-dB, variable gain amplifier (VGA). Optimized for ultrasound systems, it is usable as a low noise...
Datasheet
AD8331 on Analog.com

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Reference design for cascading all 4 channels in an AD8334 amplifier?

		
	
				

			

									
					    johntang
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Apr 16, 2026 
				
			
			
		

		
		                     
				
        		

		    
		    		    

		      		            		        
Category: Hardware

    		        		            		    
Product Number:  AD8334  

    		        		    		    

		    		    
		    			

			    
Hi,


A ~80dB VGA circuit that we have been using is literally two AD8331 EVAL circuits connected together, and I'm hoping to replace them with a single AD8334 with all 4 channels tied together to achieve similar result with less components.


Is it possible to connect the VOL1/VOH1 to VIN2/VIP2, then VOL2/VOH2 to VIN3/VIP3, VOL3/VOH3 to VIN4/VIP4 respectively, bypassing LNA2, 3, 4?


Is there a reference design out there that we could use? 


Thank you!

			

			
									
		                             
                        

    

                                            
                 amplifiers
                
                                                    
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                 Variable Gain Amplifiers (VGA)
                
                                                    
                 ad8334
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			


				
	









	
    
	

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Apr 24, 2026 1:33 AM
            
            
						
			            		
    
		
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    Hi  

    Yes, you can cascade the channels of AD8334. However, please note that AD8334 does not provide independent gain control for each channel. Instead, Channels 1 and 2 share GAIN12, and Channels 3 and 4 share GAIN34, so gain must be planned carefully. You may also want to consider bandwidth and noise accumulation to ensure stability and linearity.

    Regarding a dedicated reference design, we do not have one for cascading all four channels. That said, we do have AD8334-EVALZ available for prototyping and validation which may serve as starting point for evaluating cascaded configurations.

    Best Regards,
    Ian
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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