Products Mentioned

AD9042 Production
The AD9042 is a high speed, high performance, low power, monolithic 12-bit analog-to-digital converter. All necessary functions, including track-and-hold...
Datasheet
AD9042 on Analog.com

Associated Drivers

AD6645 Production
The AD6645 is a high speed, high performance, monolithic 14-bit analog-to-digital converter (ADC). All necessary functions, including track-and-hold (T...
Datasheet
AD6645 on Analog.com

Associated Drivers

AD9246 Production
The AD9246 is a monolithic, single 1.8 V supply, 14-bit, 80 MSPS/ 105 MSPS/125 MSPS analog-to-digital converter (ADC), featuring a high performance sample...
Datasheet
AD9246 on Analog.com

Associated Drivers

AD9254 Production
The AD9254 is a monolithic, single 1.8 V supply, 14-bit, 150 MSPS analog-to-digital converter (ADC), featuring a high performance sample-and-hold amplifier...
Datasheet
AD9254 on Analog.com

Associated Drivers

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High Speed ADC with Bipolar Analog Input



		

			

									
					    dkp
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jul 3, 2018 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello,
    
 
       I required an high speed ADC with bipolar analog input ranging from -V to +V. I was considering AD9042 but later on it came to my notice that it does not take in bipolar analog input. So, right now I am considering the following ADC's for the same purpose:
    
 
    1. AD9246
    
 
    2. AD9254
    
 
    3. AD6645
    
 
          I do not have any information yet regarding whether these devices take in bipolar analog input or not. I request you to inform me whether any of these devices fulfills my requirement.
    
 
    Thanks
    
 
    Regards
    
 
    Darshil Patel
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 ad9042
                
                                                    
                 ad6645
                
                                                    
                 High Speed A/D Converters >10 MSPS
                
                                                    
                 ad9246
                
                                                    
                 high speed adc
                
                                        
                                            
                
                
                                        
                                            
                
                
                                        
                                            
                
                
                                
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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jul 5, 2018 7:00 PM
            
            
					
      
	
      

		
		
      
					
      Hi Darshil,
      
 
      I agree with what Tony said. Yes, differential input means that the difference of the two input signals determines the ADC differential input amplitude. The differential amplitude is the voltage on one input referenced to the other differential input (not referenced to ground). So, with differential inputs you can have a negative input voltage with both input signals being positive with respect to ground.
      
 
      It sounds like you are looking to convert a single-ended signal that is from -5V to +5V with respect to ground. The ADCs I am familiar with will have problems applying a voltage that goes more negative than the ground reference.
      
 
      One possibility is to use an amplifier such as ADA4932 with its supplies connected to +5V and -5V. This could do the single-ended-to-differential conversion (and attenuation, gain <1) so the signal will be compatible with an ADC with differential inputs.
      
 
      Thanks,
      
 
      Doug
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jul 5, 2018 7:00 PM
            
            
					
      
	
      

		
		
      
					
      Hi Darshil,
      
 
      I agree with what Tony said. Yes, differential input means that the difference of the two input signals determines the ADC differential input amplitude. The differential amplitude is the voltage on one input referenced to the other differential input (not referenced to ground). So, with differential inputs you can have a negative input voltage with both input signals being positive with respect to ground.
      
 
      It sounds like you are looking to convert a single-ended signal that is from -5V to +5V with respect to ground. The ADCs I am familiar with will have problems applying a voltage that goes more negative than the ground reference.
      
 
      One possibility is to use an amplifier such as ADA4932 with its supplies connected to +5V and -5V. This could do the single-ended-to-differential conversion (and attenuation, gain <1) so the signal will be compatible with an ADC with differential inputs.
      
 
      Thanks,
      
 
      Doug
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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