CS48L32 datasheet(23/192 Pages) CIRRUS

23 / 192 page

Cirrus Logic

DS1219F4

CS48L32

4.2 Input Signal Path

System clocking can be derived from the MCLK1 input pin. Alternatively, a digital audio interface operating in Slave Mode

(ASP or PDM) can be used to provide a clock reference. The CS48L32 also provides an integrated FLL circuit for clock

frequency conversion and stability. The flexible clocking architecture supports low-power always-on operation, with

reference frequencies down to 32 kHz. Seamless switching between clock sources is supported; free-running FLL modes

are also available.

The CS48L32 is configured using control registers, accessed via a slave SPI interface operating at up to 50 MHz. The

simple analog architecture, combined with the integrated tone generator, enables straightforward device configuration and

testing, minimizing debug time and reducing software effort.

The CS48L32 is powered from 1.2 V and 1.8 V external supplies. Integrated charge-pump and LDO-regulator circuits are

used to generate supply rails for internal functions and to support powering or biasing of external microphones. Power

consumption is optimized across a wide variety of voice and multimedia use cases.

4.2 Input Signal Path

The CS48L32 provides flexible input channels, supporting up to four analog inputs or up to four digital inputs. Selectable

combinations of analog (mic or line) and digital inputs are multiplexed into two stereo input signal paths. Input path IN1

supports analog and digital inputs; input path IN2 supports digital inputs only.

The analog input paths support single-ended and differential configurations, programmable gain control, and are digitized

using a high performance sigma-delta ADC. The analog input paths can be configured for low-power operation, ideal for

always-on applications.

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

supported for two stereo pairs of digital microphones. Digital outputs can be configured on the auxiliary PDM interfaces;

these can be sourced from either the analog input or the digital PDM inputs.

The microphone bias (MICBIAS) generator provides a low-noise reference for biasing electret condenser microphones

(ECMs) or for use as a low-noise supply for MEMS microphones and digital microphones. Switchable outputs from the

MICBIAS generator allows three separate reference/supply outputs to be independently controlled.

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

operation. A configurable signal-detect function is available on each input signal path. Ultrasonic signal detection and

demodulation functions are provided on the input signal paths, supporting a variety of presence-detection applications.

The input signal paths and control fields are shown in Fig. 4-2.

CS48L32 Datasheet(PDF) 23 Page - Cirrus Logic