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ADM3222 Production
The ADM3202 / ADM3222 / ADM1385 are high speed, 2-channel RS232/V.28 interface devices which operate from a single +3.3 V power supply. Low power consumption...
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ADM3222 on Analog.com

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ADM3222 SD floating



		

			

									
					    AWANG01
					
							

			
				
									
											
			
			
				
  •  Analog Employees  

			
			
			    	
			                    
                
				                on Nov 29, 2023 
				
			
			
		


				
		

		    		    
		    
		    		      		            		        
Category: Hardware

    		        		            		    
Product Number:  ADM3222 

    		        		    		    	
			
Hi Team,


Customer is asking if there is any weak pull-up inside SD pin?


Customer cannot modify the PCB, currently short to GND with 0 ohm.


Can we suggest to add 0.1uF or 1uF at SD to GND to stabilize the weak pull-up? Thanks!


Regards,


Andrew

									
			        
		


				
						
        

    
Tags: 
                                            
                 interface and isolation
                
                                                    
                 RS-232 and RS-562
                
                                                    
                 hardware
                
                                                    
                 RS-232 / RS-422 / RS-485 / RS-562
                
                                                    
                 adm3222
                
                                
            

    
    

		

			
						
									
									
						
						
			
			
			
			
		


        
        

					

			





















	

	

					



			








	
	
	
	



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													+1
							
			
				
									
							        
			
			
			
    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Dec 1, 2023 12:01 AM
            

            
					
    
	
    

		
		
    
					
    Hi Andrew,
    

    /SD\ pin, active low, needs to have a valid logic high or low voltage. Connecting a zero-ohm resistor to ground makes the part in shutdown mode. Installing 0.1uF or 1uF cap wouldn’t help to pull up the logic level. If they can modify the board, they can use the same footprint to stall a pull-up resistor, and then wire the other termination of the resistor to VCC instead of GND, assuming they can separate the ground connection from the resistor footprint.
    

    Best,
    

    Jane
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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													+1
							
			
				
									
							        
			
			
			
    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Dec 1, 2023 12:01 AM
            

            
					
    
	
    

		
		
    
					
    Hi Andrew,
    

    /SD\ pin, active low, needs to have a valid logic high or low voltage. Connecting a zero-ohm resistor to ground makes the part in shutdown mode. Installing 0.1uF or 1uF cap wouldn’t help to pull up the logic level. If they can modify the board, they can use the same footprint to stall a pull-up resistor, and then wire the other termination of the resistor to VCC instead of GND, assuming they can separate the ground connection from the resistor footprint.
    

    Best,
    

    Jane
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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