PCM51xx

Audio DAC

Linear

Regulator

3V3

10 F

GND

GND

SMPS

6V

GND

XSMT

110V / 220V

MCU GPIO

“mute” signal

3.3V

XSMT

I2S Clocks

SCK, BCK, LRCK

3msec

VDD

0V

High

Low

High

Low

Time

PCM5100, PCM5101, PCM5102

www.ti.com

SLAS764B – MAY 2011 – REVISED SEPTEMBER 2012

2. Stop I2S clocks (SCK, BCK, LRCK) 3ms before powerdown as shown below:

Unplanned Shutdown

Many systems use a low-noise regulator to provide an AVDD 3.3V supply for the DAC. The XSMT Pin can take

advantage of such a feature to measure the pre-regulated output from the system SMPS to mute the DAC before

the entire SMPS discharges. Figure 37 shows how to configure such a system to use the XSMT pin. The XSMT

pin can also be used in parallel with a GPIO pin from the system microcontroller/DSP or Power Supply.

Figure 37. Using the XSMT Pin

Copyright © 2011–2012, Texas Instruments Incorporated

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