SM5843A Datasheet, PDF (17/24 Pages) Nippon Precision Circuits Inc – Audio Multi-function Digital Filter

SM5843A×1
Audio Data Input (INF1N, INF2N, IW1N,
IW2N, DI, DIL, DIR, BCKI, LRCI)
The input data format and several input pin functions
are selected by the state of INF1N and INF2N.
INF1N
LOW
LOW
HIGH
HIGH
DI/INF2N
LOW
HIGH
LOW
HIGH
Input format
LR alternating¹, trailing data
LR alternating, leading data
LR simultaneous², leading data
Pin function selection
DI/INF2N
IW1N/DIL
IW2N/DIR
DI
IW1N
IW2N
INF2N
DIL
DIR
1. Alternating left-channel and right-channel data input on a single input DI.
2. Simultaneous left-channel and right-channel data input on two inputs, DIL and DIR, respectively.
The input data word length is selected by the state of
IW1N and IW2N when INF1N is LOW. 20-bit is
selected when INF1N is HIGH.
exceeds a certain value. There are 2 timing error val-
ues at which resynchronization occurs, selected by
the state of SYNCN.
INF1N
LOW
HIGH
IW2N/DIL
LOW
LOW
HIGH
HIGH
×
IW1N/DIR
LOW
HIGH
LOW
HIGH
×
Input bit length
20 bits
20 bits
18 bits
16 bits
20 bits
Jitter-free mode (SYNCN = HIGH)
When SYNCN is HIGH, the timing error value is
±3/8 × (LRCI clock period). When the difference
between the input timing and LRCI start edge posi-
tion do not exceed this value, internal timing is not
resynchronized and all functions continue to operate
normally.
Jitter-free Function (SYNCN)
The arithmetic circuit and output control timing is
derived from the system clock, and is therefore inde-
pendent of the input LRCI and BCKI clocks.
Accordingly, any jitter in the data input clock (LRCI
and BCKI) does not cause jitter in the output.
Generally, the internal timing is synchronized to the
LRCI input timing after a system reset release, when
RSTN goes from LOW to HIGH, on the first LRCI
clock start edge. If the input timing and LRCI start
edge timing subsequently drift, the input timing is
automatically resynchronized when the timing error
Sync mode (SYNCN = LOW)
When SYNCN is LOW, the timing error value is ±1
× (system clock period), which is a much smaller
timing error tolerance than in jitter-free mode. In this
mode, the internal timing is guaranteed to follow the
LRCI clock timing within this tolerance, making this
mode useful for systems constructed from a multiple
number of SM5843A×1 devices.
Note that resynchronization affects the internal oper-
ation and can generate a momentary click noise out-
put.
Audio Data Output (DOL, DOR, BCKO, WCKO, OW20N)
The output data is in serial, simultaneous left and
right-channel, 2s complement, MSB first, BCKO
burst (NPC format) format. The output data word
length is selected by the state of OW20N. 18-bit out-
put is selected when OW20N is HIGH, and 20-bit
output when OW20N is LOW.
8fs serial data is output in sync with the falling edge
of the internal system clock and BCKO clock. The
number of BCKO bit clock pulses per word changes
depending on the output bit length selected (18/20
bits). Consequently, output data is latched into the
internal output register on the falling of the edge of
an output word clock WCKO, which has timing
independent of the number of output bits as specified
in the following table.
Parameter
Bit clock rate
Data word length
Symbol
T_B
T_DW
CKSLN = HIGH
1/192fs
24t_SYS
CKSLN = LOW
1/256fs
32t_SYS
NIPPON PRECISION CIRCUITS—17