AK4628A Datasheet, PDF (28/41 Pages) Asahi Kasei Microsystems – High Performance Multi-channel Audio CODEC

ASAHI KASEI
[AK4628A]
„ DAC partial Power-Down Function
All DACs of AK4628A can be powered-down individually by PD1-4 bits. The analog part of DAC is in power-down by
PD1-4 bits =”1”, however, the digital part is not in power-down by it. Even if all DACs were set in power-down by the
partial power-down bits, the digital part continue to function. The analog output of the channel which is set in
power-down by PD1-4 bits is fixed to the voltage of VCOM. And though DZF detection is being done, the result of DZF
detection stops reflecting to DZF1-2 pins. Because some click noise occurs in both set-up and release of power-down,
either the analog output should be muted externally or PD1-4 bits should be set up when it is in PWDAN bit =”0” or
RSTN bit =”0”, if the click noise influences system application. Figure 16 shows the sequence of the power-down and the
power-up by PD1-4 bits.
PD1-4 bit
Power Down Channel
DAC Digital
Internal State
Normal Operation
DAC Analog
Internal State
Normal Operation Power-down
Normal Operation
Power-down NormNaol rOmpaelrOatpioenration
DAC In
(Digital)
DAC Out
(Analog)
(1)
GD
(3) ₍₂₎
“0”data
(3)
GD
(3) ₍₂₎ (3)
8192/fs
DZF Detect
Internal State
(4)
(4)
Normal Operation Channel
DAC In
(Digital)
“0”data
GD
GD
DAC Out
(Analog)
8192/fs
DZF Detect
Internal State
Clock In
MCLK,LRCK,SCLK
(5)
DZF1/DZF2
(6)
Notes:
(1) Digital output corresponding to analog input and analog output corresponding to digital input have the group delay
(GD).
(2) Analog output of the DAC powered down by PD1-4 =”1” is fixed to the voltage of VCOM.
(3) Immediately after PD1-4 bits are changed, some click noise occurs at the output of the channel changed by the own
PD bits.
(4) Though DZF detection is being done at a certain channel which set up PD1-4 =”1”, the result of DZF detection
stops reflecting to DZF1-2 pins.
(5) DZF detection of the DAC which is set up by the power-down setting is ignored, and DZF1-2 pins become ”H”.
(6) When the power-down function is set up and the channel has input signal, even if the partial power-down function
is set up, DZF1-2 bits do not become ”H”.
Figure 16. DAC partial power-down example
MS0385-E-00
- 28 -
2005/02