Z zesla New Member Jun 22, 2011 #1 Hi, the datasheet of LM3875 says that Ci Is: ""Feedback capacitor. Ensures unity gain at DC. Also a low frequency pole (highpass roll-off) at: fc = 1/(2π Ri Ci)"" What is the meaning of the blue one? Thanks Attachments untitled7.PNG 23.8 KB · Views: 129
Hi, the datasheet of LM3875 says that Ci Is: ""Feedback capacitor. Ensures unity gain at DC. Also a low frequency pole (highpass roll-off) at: fc = 1/(2π Ri Ci)"" What is the meaning of the blue one? Thanks
crutschow Well-Known Member Most Helpful Member Jun 22, 2011 #2 It means that the gain will decrease as the frequency is reduced below the -3dB point of fc. The circuit has a gain of 1 at DC and increases to a maximum gain of 21 at a frequency above fc. The gain would be -3dB (14.87) at fc. Edit: Attached is a simulation of the circuit frequency response (fc = 7.2Hz). Last edited: Jun 22, 2011
It means that the gain will decrease as the frequency is reduced below the -3dB point of fc. The circuit has a gain of 1 at DC and increases to a maximum gain of 21 at a frequency above fc. The gain would be -3dB (14.87) at fc. Edit: Attached is a simulation of the circuit frequency response (fc = 7.2Hz).