Datasheet

SRC4194 Product Overview
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1.1 SRC4194 Product Overview
The SRC4194 is a four-channel, asynchronous sample rate converter
(ASRC), implemented as two stereo sections referred to as SRC A and SRC
B. Operation at input and output sampling frequencies up to 212kHz is
supported, with a continuous input/output sampling ratio range of 16:1 to 1:16.
Excellent dynamic range and THD+N are achieved by employing high
performance, linear phase digital filtering with better than 140dB of image
rejection. The digital filters provide settings for lower latency processing,
including low group delay options for the interpolation filter and a direct
down-sampling option for the decimation filter. Digital de-emphasis filtering is
also included, supporting 32kHz, 44.1kHz, and 48kHz input sampling
frequencies.
The audio input and output ports support standard audio data formats, as well
as a time division multiplexed (TDM) format. Word lengths of 24, 20, 18, and
16 bits are supported. Input and output ports may operate in Slave mode, de-
riving their word and bit clocks from external input and output devices. Alterna-
tively, one port may operate in Master mode while the other remains in Slave
mode. In Master mode, the LRCK and BCK clocks are derived from the refer-
ence clock inputs, either RCKIA or RCKIB. The flexible configuration options
for the input and output ports allows connection to a variety of audio data con-
verters, digital audio interface devices, and digital signal processors.
A bypass mode is included, which allows audio data to be passed directly from
the input port to the output port, bypassing the ASRC function. The bypass op-
tion is useful for passing through compressed or encoded audio data, as well
as non-audio data (that is, control or status information).
A soft mute function is available for the SRC4194 in both Hardware and Soft-
ware modes. Digital output attenuation is available only in Software mode.
Both soft mute and digital attenuation functions provide artifact-free operation.
The mute attenuation is typically −144dB, while the digital attenuation function
is programmable from 0dB to −127.5dB in 0.5dB steps.
The SRC4194 includes a four-wire SPI port, which is used to access on-chip
control and status registers in Software mode. The SPI port facilitates interfac-
ing to microprocessors or digital signal processors that support synchronous
serial peripherals. In Hardware (or Standalone) mode, dedicated control pins
are provided for the majority of the SRC4194 functions. These pins can be ei-
ther hardwired or driven by logic or host control.