CS47L85 datasheet(47/370 Pages) CIRRUS

47 / 370 page

CS47L85

Rev 4.3

INPUT SIGNAL PATH

The CS47L85 provides flexible input channels, supporting up to 9 analogue inputs or up to 12 digital inputs. Selectable

combinations of analogue (mic or line) and digital inputs are multiplexed into 6 stereo input signal paths. Input paths IN1,

IN2 and IN3 support analogue and digital inputs; Input paths IN4, IN5 and IN6 support digital inputs only.

The analogue input paths support single-ended and differential modes, programmable gain control and are digitised using

a high performance 24-bit sigma-delta ADC.

The digital input paths interface directly with external digital microphones; a separate microphone interface clock is provided

for six separate stereo pairs of digital microphones. Digital delay can be applied to any of the digital input paths; this can be

used for phase adjustment of any digital input, including directional control of multiple microphones.

Four microphone bias (MICBIAS) generators are available, which provide a low noise reference for biasing electret

condenser microphones (ECMs) or for use as a low noise supply for MEMS microphones and digital microphones.

Digital volume control is available on all inputs (analogue and digital), with programmable ramp control for smooth, glitch-

free operation. Any of the analogue or digital inputs may be selected as input to the Ambient Noise Cancellation (ANC)

processing function.

The signal paths and control registers for inputs IN1, IN2 and IN3 are illustrated in Figure 13. The IN4, IN5 and IN6 signal

paths supports digital microphone input only.

CS47L85 Datasheet(PDF) 47 Page - Cirrus Logic