XE3005 ETC, XE3005 Datasheet - Page 9

• Manufacturer Part Number: XE3005
• Description: (XE3005 / XE3006) Low-Power Audio CODEC
• Manufacturer: ETC

2.1.9
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).
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).
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.
9
On-time counter
Off-time counter
Sandman™ DAC Function
SMAD
(SMDA)
AIN/SDO
(AOUT/SDI)
Figure 8: Implementation of the Sandman function for the DAC (SMDA)
FSYNC
BCLK
1 2
SDI
Figure 9: Illustration of the Sandman™ function.
Serial Audio
Interface
3
on-time
4
Sandman
Interface
5
6
PWM
7
DAC
Reg I, bit 4
amplifier
Power
8
9
Time step = 1/fs = 1/FSYNC
SMDA
VDDPA
AOUTP
AOUTN
VSSPA
off-time
Data Sheet
XE3005/XE3006
- reference
+ reference
10 time
D0212-116