Products Mentioned

MAX4210 Production
The MAX4210/MAX4211 low-cost, low-power, high-side power/current monitors provide an analog output voltage proportional to the power consumed by a load...
Datasheet
MAX4210 on Analog.com

Thread Details

  • State Not Answered
  • Replies 1 reply
  • Subscribers 2 subscribers
  • Views 73 views
  • Users 0 members are here
Options
 
Related Content

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
MAX4210 constant power source oscillates

		
	
				

			

									
					    Topspin
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 15, 2026 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  MAX4210  
    
    		        		    		    
    
		    		    
		    			
    
			    
    Hi all,
    

    I am testing a circuit like this. The IC1 in my case is the MAX4210D and Rsense=1R,Rlimit1=0,Rlimit2=1000R,R1=11k and R2=680R. V+ is 10V and Vcc 5V
    

     
    

    I have tested two opamp: opamp 1 phase margin 50° and opamp2 phase margin 80°.
    

    With opamp2 the circuit works quite well ( only few ringing)
    

     
    

    While with opamp1 the circuit oscillates
    

     
    

    Oscillation occurs at around 50kHz
    

     
    

    Since my goal is to use opamp 1 given other opamp specs, can you suggest how to stabilize the circuit? Vset change very slowly so I am not interested in reaching high bandwidth
    

    i tried to insert a capacitor here but the oscillation only goes to lower frequency 
    

     
    

    I hope you can help
    
			
    
			
									
		                             
                        

    
    
                                            
                 hardware
                
                                                    
                 MAX4210
                
                                                    
                 Specialty Amplifiers
                
                                                    
                 Current Sense Amplifiers
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



Parents
	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
		    
		    		    
			
				
									
							        
			
			
			
        
            
						
                            
            
            				
            
                on Jan 15, 2026 11:37 AM
            
            
						
			            		
        
		
										0
					
	
        

		
		
        
		
        
                                
                                                            
        
					
        Hello Topspin, 
        

        if you want to compensate your feedback loop of the opamp, it is not sufficient to add capacitive feedback. Cause the feedback capacitor goes directly to the low impedant output of the MAX4210. The output driver at pin 8 of the MAX4210 competes directly with the capacitive feedback of your opamp. The compensation may work, if you add not only the capacitor, but also a resistor as shown below. 
        

         
        

        I think your oscillation frequency is ~100kHz? Then you may try an RC-combination in the range of R·C≈1µs to get some additional phase margin for your opamp. 
        

        best regards
        

        Achim
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

        • 

	
      



Reply

        


      • 
	
        



	
		
	
	



        
	
        
		
        
							
					
        
		
        
		    
		    		    
			
				
									
							        
			
			
			
          
            
						
                            
            
            				
            
                on Jan 15, 2026 11:37 AM
            
            
						
			            		
          
		
										0
					
	
          

		
		
          
		
          
                                
                                                            
          
					
          Hello Topspin, 
          

          if you want to compensate your feedback loop of the opamp, it is not sufficient to add capacitive feedback. Cause the feedback capacitor goes directly to the low impedant output of the MAX4210. The output driver at pin 8 of the MAX4210 competes directly with the capacitive feedback of your opamp. The compensation may work, if you add not only the capacitor, but also a resistor as shown below. 
          

           
          

          I think your oscillation frequency is ~100kHz? Then you may try an RC-combination in the range of R·C≈1µs to get some additional phase margin for your opamp. 
          

          best regards
          

          Achim
          
			
          

		
			
	      

		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

          • 


        


Children
	
        No Data
        

		
			
        

        





		
        
		
        
			
          
				
        • 
					
												
						
						
						
						
						
						
						

																										
						
						

					
					
					
				
          •