
ASAHI KASEI
[AK4534]
MS0133-E-03
2003/5
- 59 -
n
Headphone-amp Output
FS2-0 bits
(Addr:05H, D7-5)
(Addr:0CH 0DH, D7-0)
PMDAC bit
(Addr:01H, D0)
PMHPL/R bits
(Addr:01H, D2-1)
HPL/R pins
XXX
000
0000000
XXXXXXX
Normal Output
External Mute
(1)
BST1-0 bits
(Addr:06H, D3-2)
00
XX
00
(2)
(3)
(4)
(5)
(6)
(7)
(8)
E xam p le :
X ’tal and PLL are used.
S a m p ling Frequency : 44.1kH z
D A T T C b it = “1”(default)
D igital A ttenuato r Level : -8dB
B a s s B o o s t Level : M iddle
D e-emphases response : OFF
S o ft M ute Tim e : 1024/fs
(1) A d d r:05H, Data:00H
(3 ) A d d r:0C H , Data 10H
(4) A d d r:01H, Data 67H
(5) R e lease external M u te
P layback
(2) A d d r:06H, Data 19H
(6) E n a b le external M u te
(7) A d d r:01H, Data 60H
(8) A d d r:06H, Data 11H
Figure 39. Headphone-Amp Output Sequence
<Example>
At first, clocks should be supplied according to “Clock Set Up” sequence.
(1) Set up a sampling frequency (FS2-0 bits) if PLL mode is used.
(2) Set up the low frequency boost level(BST1-0 bits)
(3) Set up the digital volume(Addr : 0CH and 0DH)
At DATTC bit = “1”(default), ATTL7-0 bits of Address 0CH control both Lch and Rch attenuation level.
(4) Power up DAC and headphone-amp : PMDAC bit = PMHPL bit = PMHPR bit = “0”
→
“1”
The rising time after power up Headphone-amp depends on the capacitor value connected with the MUTET
pin. When this capacitor value is 1.0
μ
F, the time constant is
τ
r
= 100ms.
(5) Release the external mute.
(6) Enable the external mute.
(7) Power down DAC and headphone-amp : PMDAC bit = PMHPL bit = PMHPR bit = “1”
→
“0”
The falling time of Headphone-amp depends on the capacitor for the AC couple of Headphone-amp output.
When this capacitor value is 47
μ
F, the time constant is
τ
f
= 188ms. If the power supply is powered off or
Headphone-Amp is powered-up again before the common voltage goes to GND, some POP noise occurs. It
takes 5times of
τ
f
that the common voltage goes to GND.
(8) Off the low frequency boost level (BST1-0 bits = “00”)