Data Sheet

XE3005/XE3006

9

D0212-116

2.1.9

Sandman™ DAC Function

The Sandman™ function monitors the signals, which are processed in the ADC signal, channel and the DAC

signal channel. The logic output signal SMDA indicates whether the DAC signal channel processes an audio

signal or only noise, and this for certain duration. The reference signal amplitude can be selected through register

P, the time window parameters are the off time and on time (registers L, M and N).

Serial Audio

Interface

BCLK

FSYNC

SDI

PWM

DAC

Power

amplifier

AOUTP

AOUTN

VDDPA

VSSPA

SMDA

Sandman

Interface

Reg I, bit 4

Figure 8: Implementation of the Sandman function for the DAC (SMDA)

The logic output SMDA can be employed to power-down other devices in the application, such as an external

audio power amplifier. By setting bit 4 in register I, the on-chip DAC signal channel can be powered-down through

SMDA too. The Sandman™ function is illustrated in Figure 9 and is valid for both SMAD (related to the ADC

signal) and SMDA (related to the DAC signal).

off-time

on-time

AIN/SDO

(AOUT/SDI)

SMAD

(SMDA)

On-time counter

Off-time counter

+ reference

- reference

Time step = 1/fs = 1/FSYNC

12

9

38

7

6

45

10 time

Figure 9: Illustration of the Sandman™ function.

The above illustration is valid for either the SMAD output as a result of AIN/SDO or for the SMDA output as a

function of AOUT/SDI.