WM8952ECSSLASHRV datasheet(16/72 Pages) WOLFSON

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WM8952

Pre Production

PP, Rev 3.1, June 2011

may then be output on the GPIO pin and used elsewhere in the system.

POWER CONTROL

The design of the WM8952 has given much attention to power consumption without compromising

performance. It operates at low supply voltages, and includes the facility to power off any unused

parts of the circuitry under software control.

As a power saving measure, ADC logic in the DSP core is held in its last enabled state when the

ADC is disabled. In order to prevent pops and clicks on restart due to residual data in the filters, the

master clock must remain for at least 64 input samples after the ADC has been disabled.

INPUT SIGNAL PATH

The WM8952 has 3 flexible analogue inputs: two microphone inputs, and an auxiliary input. These

inputs can be used in a variety of ways. The input signal path before the ADC has a flexible PGA

block which then feeds into a gain boost/mixer stage.

MICROPHONE INPUTS

The WM8952 can accommodate a variety of microphone configurations including single ended and

differential inputs. The inputs through the MICN, MICP and optionally AUX pins are amplified through

the input PGA as shown in Figure 6 .

A pseudo differential input is the preferential configuration where the positive terminal of the input

PGA is connected to the MICP input pin by setting MICP2INPPGA=1. The microphone ground

should then be connected to MICN (when MICN2INPPGA=1) or optionally to AUX (when

AUX2INPPGA=1) input pins.

Alternatively a single ended microphone can be connected to the MICN input with MICN2INPPGA set

to 1. The non-inverting terminal of the input PGA should be connected internally to VMID by setting

MICP2INPPGA to 0.

In pseudo-differential mode the larger signal should be input to MICP and the smaller (e.g. noisy

ground connections) should be input to MICN.

Figure 6 Microphone Input PGA Circuit (switch positions shown are for differential mic

input)

WM8952ECS/RV Scheda tecnica(PDF) 16 Page - Wolfson Microelectronics plc