Products Mentioned

SSM2518 Production
The SSM2518 is a digital input, Class-D power amplifier that combines a digital-to-analog converter (DAC) and a sigma-delta (S-?) Class-D modulator. This...
Datasheet
SSM2518 on Analog.com

  • State Not Answered
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 222 views
  • Users 0 members are here
Options
Similar Content 

        

            Post
             Go back to editing
        

    

    


    

    









		












	
	
			
	
			
		
	
	
		

		
SSM2518 hiss while sending zero signal



		

			

									
					    AWS
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Sep 15, 2023 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  SSM2518 
    
    		        		    		    	
			
    We are using the SSM2518 in an MCU design - it is driven via I2S output from an LPC5506 MCU. We are using a wide variety of MCLK speeds and configurations to support many file sample rates, but most are 48kHz 16-bit short audio samples. Our code is set up to un-mute the amplifier, play the audio sample, and then re-mute the amplifier.
    

    

    We observe a distinct and very audible hissing sound, both while audio is playing, and most importantly after the amplifier has been commanded to soft mute. 
    

    

    The amplifier is configured with the right channel disabled - we only need mono output.
    

    We also have volume link enabled, which feels like it could cause an issue. However, I have tried disabling it and have not noticed any problem. 
    

    

    I have seen another identical question on this forum that had been marked as resolved, but did not offer a solution. Any ideas?
    

    

    Thank you,
    

    Alex
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Speaker Amplifiers
                
                                                    
                 Audio Products
                
                                                    
                 hardware
                
                                                    
                 ssm2518
                
                                                    
                 Audio Amplifiers
                
                                        
                                            
                
                
                                
                    Show More
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Sep 22, 2023 2:19 PM
            
            
					
      
	
      

		
		
      
					
      Hi Alex,
      

      I'd be happy to help troubleshoot this problem.
      

      Would you be able to provide me with a list of the register writes/status reads and the schematic of your setup? 
      

      From reading the details of you setup, it seems the SSM2518 could be caught in a cycle of Unlimited Automatic Recovery Attempts and Over Current/Temperature Recovery Fault conditions.
      

      If you were to change the Number of Auto Recovery Attempts to one of the 1/3/7 Attempts options, the amplifier should turn off after the selected Auto Recovery Time. Once it's turned off, try toggling the Manual Fault Recovery Attempt bits to see if the hiss sound persists. 
      

      If you have any other questions, please feel free to reach out. If you can provide me with the list of register writes and status reads along with the schematic of your setup, we should be able to figure out this issue rather quickly. Thanks!
      

      Best,
      

      TM
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

      •