Cirrus Logic CS4354 - Manual (Page 13)

DS895F2 13
CS4354
4. APPLICATIONS
4.1 Ground-Centered Line Outputs
An on-chip charge pump creates a negative supply which allows the full-scale output swing to be centered
around ground. This eliminates the need for large DC-blocking capacitors which create audible pops at pow-
er-on and provides improved low frequency response. See the
DAC Analog Characteristics table for the
complete specifications of the full-scale output voltage. It should be noted that external output impedance
between the AOUTx pin and the load will lower the voltage delivered to the load.
4.2 Sample Rate Range/Operational Mode Detect
The CS4354 operates in one of three operational modes. The device will auto-detect the correct mode when
the input sample rate (Fs), defined by the LRCK frequency, falls within one of the ranges illustrated in
Table 3 . Sample rates outside the specified range for each mode are not supported. In addition to a valid
LRCK frequency, a valid serial clock (SCLK) and master clock (MCLK) must also be applied to the device
for speed mode auto-detection; see
Figure 9 .
Table 3. CS4354 Operational Mode Auto-Detect
4.3 System Clocking
The device requires external generation of the master (MCLK), left/right (LRCK) and serial (SCLK) clocks.
The left/right clock, defined also as the input sample rate (Fs), must be synchronously derived from the
MCLK signal according to specified ratios. The specified ratios of MCLK to LRCK, along with several stan-
dard audio sample rates and the required MCLK frequency, are illustrated in
Table 4 on page 13 .
Refer to Section 4.6 for the required SCLK timing associated with the selected Digital Interface Format and
to “Switching Specifications - Serial Audio Interface” on page 8 for the maximum allowed clock frequencies.
Table 4. Common MCLK and LRCK Frequencies
Input Sample Rate (Fs) Mode
30 kHz - 54 kHz Single-Speed Mode
84 kHz - 108 kHz Double-Speed Mode
170 kHz - 216 kHz Quad-Speed Mode
LRCK
(kHz)
MCLK (MHz)
128x 192x 256x 384x 512x 768x 1024x
32 - - 8.1920 12.2880 16.3840 24.5760 32.7680
44.1 - - 11.2896 16.9344 22.5792 33.8688 45.1580
48 - - 12.2880 18.4320 24.5760 36.8640 49.1520
88.2 11.2896 16.9344 22.5792 33.8688 45.1584 - -
96 12.2880 18.4320 24.5760 36.8640 49.1520 - -
176.4 22.5792 33.8688 45.1584 - - - -
192 24.5760 36.8640 49.1520 - - - -
Mode QSM DSM SSM