Figure 21. dsd phase modulation mode diagram, 9 grounding and power supply arrangements, 1 capacitor placement – Cirrus Logic CS4385A User Manual

Page 28: Figure 21.dsd phase modulation mode diagram, Figure 21, Use o, Cs4385a

DS837F2

CS4385A

4.9

Grounding and Power Supply Arrangements

As with any high-resolution converter, the CS4385A requires careful attention to power supply and ground-
ing arrangements if optimal potential performance levels are to be realized. The Typical Connection Dia-
gram shows the recommended power arrangements, with VA, VD, VLC, and VLS connected to clean
supplies. If the ground planes are split between digital ground and analog ground, the GND pins of the
CS4385A should be connected to the analog ground plane.

Note:

All signals, especially clocks, should be kept away from the FILT+ and VQ pins in order to avoid
unwanted coupling into the DAC.

4.9.1

Capacitor Placement

Decoupling capacitors should be placed as close to the DAC as possible, with the low value ceramic ca-
pacitor being the closest. To further minimize impedance, these capacitors should be located on the same
layer as the DAC. If desired, all supply pins with similar voltage ratings may be connected to the same
supply, but a decoupling capacitor should still be placed on each supply pin.

Note: All decoupling capacitors should be referenced to ground.

BCKA

(128Fs)

BCKD

(64Fs)

DSD_SCLK

DSDAx,

DSDBx

DSD_SCLK

DSDAx,

DSDBx

BCKA

(64Fs)

DSD_SCLK

DSD Phase

Modulation Mode

DSD Normal Mode

Not Used

Figure 21. DSD Phase Modulation Mode Diagram