Clock-Halt Reset

SCKI

T0081-01

48/fin or 48/fS

Fade-In Start

Fade-In Complete

Internal

Reset

Operation

Operation

DOUT

Normal Data

Normal Data

DOUT

(Contents)

Normal Data

SCKI Halt

SCKI Resume

Fixed to Low or High

t(CKR)

Reset: t(RST)

Reset Release: t(REL)

BPZ

Zero Data

PCM1808-Q1

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SLES265A – MARCH 2011 – REVISED AUGUST 2012

CLOCK-HALT POWER-DOWN AND RESET FUNCTION

The PCM1808-Q1 has a power-down and reset function, which is triggered by halting SCKI (pin 6) in both

master and slave modes. The function is available anytime after power on. Reset and power down are performed

automatically 4

μs (minimum) after SCKI is halted. While the clock-halt reset is asserted, the PCM1808-Q1 stays

in the reset and power-down mode, and DOUT (pin 9) is forced to zero. SCKI must be supplied to release the

reset and power-down mode. The digital output is valid after the reset state is released and the time of 1024

SCKI + 8960/fS has elapsed. Because the fade-in operation is performed, it takes additional time of 48/fin or 48/fS

until the level corresponding to the analog input signal is obtained. Figure 20 illustrates the clock-halt reset

timing.

To avoid ADC performance degradation, BCK (pin 8) and LRCK (pin 7) are required to synchronize with SCKI

within 4480/fS after SCKI is resumed. If it takes more than 4480/fS for BCK and LRCK to synchronize with SCKI,

SCKI should be masked until the synchronization is achieved again, taking care of glitch and jitter. See the

typical circuit connection diagram, Figure 26.

To avoid ADC performance degradation, the clock-halt reset also should be asserted when system clock SCKIor

the audio interface clocks BCK and LRCK (sampling rate fS) are changed on the fly.

SYMBOL

PARAMETER

MIN

MAX

UNIT

t(CKR)

Delay time from SCKI halt to internal reset

4

μs

t(RST)

Delay time from SCKI resume to reset release

1024 SCKI

μs

t(REL)

Delay time from reset release to DOUT output

8960/fS

μs

Figure 20. Clock-Halt Power-Down and Reset Timing

Copyright © 2011–2012, Texas Instruments Incorporated

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