SM5819HQF Datasheet, PDF (14/18 Pages) Nippon Precision Circuits Inc – 6-channel DSD-PCM Converter

SM5819HQF
External input data and external system clock output switching
(1) Switching to external input data
When SELEXT is switched LOW to HIGH, the PCM data output is immediately switched to external
input data.
PLRCK and PBCK are similarly switched immediately to EXILRCK and EXIBCK in through mode,
respectively, regardless of the DIRPCK setting.
(2) Switching to external system clock
The MCKOUT system clock output can be switched between MCK and EXIMCK using SELEXT, as
given below.
SELEXT = “L”: MCK output
SELEXT = “H”: EXIMCK output
Note that neither MCK nor EXIMCK clock should be stopped during the switching interval to prevent a
micro-pulse being generated when switching.
The switching interval lasts from when SELEXT changes state until both clocks have made 4 transitions.
During this interval, the LOW-level clock pulsewidth of the first clock is extended until the rising edge of
the second clock occurs.
When the switching interval ends, the unused clock may then be stopped.
MCK
EXIMCK
SELEXT
MCKOUT
OFF
(MCK OFF)
(EXIMCK ON)
(Switching time)
Figure 2. MCK → EXIMCK switching
MCK
EXIMCK
SELEXT
MCKOUT
OFF
(EXIMCK OFF)
(MCK ON)
(Switching time)
Figure 3. EXIMCK → MCK switching
NIPPON PRECISION CIRCUITS INC.—14