Cirrus Logic CS4398 - Manual (Page 21)

DS568F1 21
CS4398
Use of the Mute Control function is not mandatory but recommended for designs requiring the absolute min-
imum in extraneous clicks and pops. Also, use of the Mute Control function can enable the system designer
to achieve idle channel noise/signal-to-noise ratios which are only limited by the external mute circuit.
Figure 12. Recommended Mute Circuitry
4.4 Oversampling Modes
The CS4398 operates in one of three oversampling modes based on the input sample rate. Single-Speed
mode supports input sample rates up to 50 kHz and uses a 128x oversampling ratio. Double-Speed mode
supports input sample rates up to 100 kHz and uses an oversampling ratio of 64x. Quad-Speed mode sup-
ports input sample rates up to 200 kHz and uses an oversampling ratio of 32x.
4.5 Master and Serial Clock Ratios
The required MCLK-to-LRCK ratio and suggested SCLK-to-LRCK ratio are outlined in Table 1. MCLK can
be at any phase in regards to LRCK and SCLK. SCLK, LRCK and SDATA must meet the phase and timing
relationships outlined in Section 2. Some common MCLK frequencies have been outlined in Table 2.
MCLK/LRCK SCLK/LRCK LRCK
Single-Speed 256, 384, 512, 768*, 1024*, 1152* 32, 48, 64, 96, 128 Fs
Double-Speed 128, 192, 256, 384, 512* 32, 48, 64 Fs
Quad-Speed
64 32 (16 bits only) Fs
96 32, 48 Fs
128, 256* 32, 64 Fs
192 32, 48, 64, 96 Fs
*These modes are only available in Control Port mode by setting the appropriate MCLKDIV bit.
Table 1. Clock Ratios