Products Mentioned

ADG751 Production
The ADG751 is a low voltage SPST (single pole, single throw) switch. It is constructed in a T-switch configuration, which results in excellent Off Isolation...
Datasheet
ADG751 on Analog.com

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ADG751 Source isolation



		

			

									
					    jacobm
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Feb 9, 2017 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello, 
    
 
    I want to use ADG751 switches for a circuit I am working on. My switches in this circuit are floating (sources are not grounded), will be this a problem using ADG751 CMOS switches? Also, I am driving the gate(switch on and off in high speed around 1MHz) using a microcontroller, do I need to have an isolation for the floating source?  or I need a bootstrap circuit to ensure turning the switches on & off ?
    
 
    Thanks
    
 
    Jacob
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 cmos switch
                
                                                    
                 Single-Supply Analog Switches and Multiplexers
                
                                                    
                 adg751
                
                                                    
                 Analog Switches Multiplexers
                
                                                    
                 switches and multiplexers
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Feb 27, 2017 9:25 AM
            
            
					
      
	
      

		
		
      
					
      Hi Jacob,
      
 
      The signal presented to the source/drain of the ADG751 needs to be between -0.3V and VDD + 0.3V so that the absolute max ratings are not violated. The absolute max ratings are referenced to the GND of the device so if the voltage source is floating you would need to be able to guarantee that the input voltage max range is not violated.
      
 
      The digital logic input high and input low voltages are also referenced to the GND of the device so the logic input signal needs to be 2.4V above the device GND for the switch to turn on.
      
 
      Regards,
      
 
      Stephen
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Feb 27, 2017 9:25 AM
            
            
					
      
	
      

		
		
      
					
      Hi Jacob,
      
 
      The signal presented to the source/drain of the ADG751 needs to be between -0.3V and VDD + 0.3V so that the absolute max ratings are not violated. The absolute max ratings are referenced to the GND of the device so if the voltage source is floating you would need to be able to guarantee that the input voltage max range is not violated.
      
 
      The digital logic input high and input low voltages are also referenced to the GND of the device so the logic input signal needs to be 2.4V above the device GND for the switch to turn on.
      
 
      Regards,
      
 
      Stephen
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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