AK4569 Datasheet, PDF (23/45 Pages) Asahi Kasei Microsystems – 20-Bit Stereo CODEC with IPGA & HP-AMP

ASAHI KASEI
[AK4569]
2) DAC → HP-amp
Power supply voltage for headphone amp is supplied from HVDD pin and centered on VCOM. Load resistance of
headphone output is min.20Ω. When PMHPL and PMHPR bit are “0”, headphone amplifiers are powered-down
perfectly. Then HPL and HPR pins are fixed to “L” (HVSS) and a capacitor of MUTET pin works to avoid pop noise.
Power Supply
PDN pin
PMVCM bit
Clock Input
PMDAC bit
DAC Internal
State
SDTI pin
PMHPL/R bit
HPLMT,
HPRMT bit
ATTL/R7-0 bit
HPL/R pin
(1)
>150ns
(2) >0
Don’t care (4)
(3) >0
PD
Normal Operation
(9)
Don’t care
PD
Normal Operation
PD
00H(MUTE)
(5)
FFH(0dB)
00H(MUTE)
(7) GD (8) 1061/fs (7) (8)
(6)
(5)
FFH(0dB) 00H(MUTE)
(7) (8) (7) (8)
(6)
Figure 18. Power-up/down sequence of DAC and HP-amp
(1) PDN pin should be set to “H” at least 150ns after the power is supplied.
(2) HPLMT, HPRMT and PMVCM bits should be changed to “1” after PDN pin goes to “H”.
(3) PMDAC, PMHPL, PMHPR bits should be changed to “1” and HPLMT, HPRMT bits should be changed to “0” after
HPLMT, HPRMT, PMVCM bits are changed to “1”. Once PMHPL and PMHPR bits are changed to “1”, HPLMT
and HPRMT bits should be inverted from PMHPL and PMHPR bits respectively.
(4) External clocks (MCLK, BICK, LRCK) are needed to operate DAC. When PMDAC bit = “0”, these clocks can be
stopped. Headphone amp can operate without these clocks.
(5) Rise time of headphone amp is determined by external capacitor of MUTET pin. When C=1µF,
Rise Time Constant of Headphone Amp: τ = 100ms
(6) Fall time of headphone amp is determined by output capacitor for AC coupling. When C=100µF,
Fall Time Constant of Headphone Amp: τ = 200ms
(7) Analog output corresponding to digital input has the group delay (GD) of 16.8/fs(=381µs@fs=44.1kHz).
(8) ATS bit sets transition time of digital attenuator. Default value is 1061/fs(=24ms@fs=44.1kHz).
(9) Power supply should be switched off after headphone amp is powered down (HPL/R pins become “L”).
MS0292-E-01
- 23 -
2005/07