The AD1986A includes many improvements that reduce external support components for particular applications. •  Multiple Microphone Sourcing: The MIC_1/2, LINE_IN and C/LFE pins can all be selected as sources for microphone input (boost amplifier).  •  Multiple VREF_OUT Pins: Each microphone-capable pin group (MIC_1/2, LINE_IN and C/LFE) has separate,  software controllable VREF_OUT pins, reducing the need for external biasing components.  •  Internal Microphone Mixing: Any combination of the MIC_1/2, LINE_IN and C/LFE pins can be summed to produce the microphone input. This removes the need for external mixing components in applications that externally mix microphone sources.•  Advanced Jack Presence Detection: Using two codec pins, eight resistors and isolated switch jacks, the AD1986A can detect jack insertion on eight separate jacks.   •  Internal Microphone/Line In/C/LFE Sharing: On  systems that share the microphone with the C/LFE jack no external components are required. The microphone  selector can select the LINE_IN pins when the microphone and line input devices are swapped.  •