Cirrus Logic AN260 - Manual (Page 5)

AN260
AN260REV2 5
• Pin 42 no longer functions as M3 in stand-alone PCM modes. It is now a dedicated DSD_SCLK pin.
Pins which require changes to external components or voltages as denoted in Figure 4 are as
follows:
• Pin 4 (VD) requires 2.5 V for recommended operation. The CS4362 used either 3.3 V or 5 V, which, if left
unchanged, would damage the CS4365.
• Pins 22-26 and pin 41 (MUTEC#) require an additional pull-up or down in order to indicate the desired
direction of mute polarity. While reset is asserted these pins are high impedance and will not drive the mute
circuitry. It is recommended that the pull-up/down resistance properly biases the off-chip mute circuit into
muting.
• Pins 27 - 30, 33 - 40 (AOUTs) have a new recommended filter circuit. This filter uses the same filter topology
as the CS4362. The component values have been changed to account for the extra output level from the
CS4365 and still provide 2 Vrms on the output. A general optimization was also made in order to reduce the
thermal noise contribution of the resistances (using smaller resistances where possible). Please refer to the
CS4365 datasheet for details on the new recommended filter.
2.2.2 Functional changes
- The CS4365 uses a new register mapping in order to accommodate the additional features which
it provides over the CS4362. Please refer to the CS4365 datasheet for the new mapping.
- With the addition of the non-decimating DSD processor mode comes the added benefits of
matched PCM and DSD output levels, DSD volume control, an on chip 50 kHz filter, Phase Mod-
ulation input mode, and DSD mute pattern detection. A direct DSD path to the switched capacitor
array is also offered. All of the features are accessed through the configuration registers.
- The CS4365 supports a setting for auto-selection of the speed mode to set what sample rate range
the DAC is to expect. This allows the CS4365 to operate at sample rates from 4 kHz on up to
192 kHz without intervention (Note: there are a few reserved frequencies, see datasheet for de-
tails). This setting is available in both stand-alone and control-port operation.
- The volume control in the CS4365 offers 0.5 dB step sizes for more volume setting resolution.
- The CS4365 offers TDM and One-Line modes for compatibility with various multi-channel sur-
round sound DSPs which helps reduce board real-estate from the additional data lines. These
modes are not available in stand-alone mode.
- The CS4365 uses a new multi-bit Delta-Sigma modulator core with mis-match shaping which al-
lows for lower over-all out-of-band noise and improved audio quality.
- The CS4365 gained new digital filters with improved stop-band performance and lower latency.
- The full-scale differential output voltage has increased which needs to be accounted for in the an-
alog filter gain (if similar output level to the CS4362 is desired).
- The mute control pins now support auto polarity detection. This allows for selection of active high
or low mute circuitry without the need to set registers. An external pull-up or down is required to
set the mute polarity.
- The MCLK divide by 2 bit is no longer necessary to access the 1024x MCLK/LRCK ratio (SSM),
512x MCLK/LRCK ratio (DSM) and 256x MCLK/LRCK ratio. A new ratio of 1152x has been added
for 32 kHz operation.
- The dual serial port function of the CS4362 which accepted two simultaneous synchronous sam-
ple rates (such as 192 kHz front and 96 kHz surrounds) is not supported.