AK4627 Datasheet, PDF (30/46 Pages) Asahi Kasei Microsystems – High Performance Multi-channel Audio CODEC

[AK4627]
■ DAC partial Power-Down Function
All DACs of AK4627 can be powered-down individually by PDDA1-3 bits. The analog part of DAC is in power-down
mode by PDDA1-3 bits = “1”, however, the digital part is not powered-down. Even if all DACs were set in power-down
mode by the partial power-down bits, the digital part continues an operation. The analog output channels which are
powered-down by PDDA1-3 bits are fixed to the VCOM voltage. Although DZF detection is in operation, DZF detection
results of these analog output channels are not reflected to DZF1-2 pins. Some click noise occurs in both set-up and
release of power-down. Mute the analog output externally or set PDDA1-3 bits when PWDAN bit = “0” or RSTN bit =
“0”, if click noise aversely affects system performance. Figure 20 shows the power-down/up sequences by PDDA1-3 bits.
PDDA1-3 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)
8192/fs
GD
(3) ₍₂₎ (3)
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 outputs corresponding to analog inputs and analog outputs corresponding to digital inputs have group delay
(GD).
(2) Analog outputs of the DAC when powered down by PDDA1-3 bits = “1” are fixed to the VCOM voltage.
(3) Immediately after PDDA1-3 bits are changed, a click noise occurs at the output of the channel which is changed by
the own PDDA bits.
(4) Although DZF detection is in operation, DZF detection results of powered-down DAC analog output channels are
not reflected to DZF1-2 pins.
(5) DZF detection of the DAC which is in power-down mode is ignored, and DZF1-2 pins become “H”.
(6) When signal is input to a DAC, even if other DACs are powered-down by partial power-down by PDDA bits,
DXF1-2 pins do not become “H”. Mute the analog output externally if the click noise influences system
applications.
Figure 20. DAC partial power-down example
MS1278-E-02
- 30 -
2012/03