AK4640_05 Datasheet, PDF (70/78 Pages) Asahi Kasei Microsystems – 16-Bit ΔΣ CODEC with MIC/HP/SPK-AMP

ASAHI KASEI
[AK4640]
„ Headphone-amp Output
FS2-0 bits
(Addr:05H, D7-5)
BST1-0 bits
(Addr:06H, D3-2)
ATTL7-0 bits
(Addr:0CH 0DH, D7-0)
PMDAC bit
(Addr:01H, D0)
HPL/R bit
(Addr:03H, D1-0)
PMHPL/R bits
(Addr:01H, D2-1)
000
(1)
00
(2)
0000000
(3)
(4)
(5)
(6)
XXX
XX
XXXXXXX
00
(10)
(9)
(8)
(7)
HPL/R pins
Normal Output
E x a m p le :
X ’ta l a n d P L L a re use d .
S am p lin g F re q u e n cy : 4 4 .1k H z
D A T T C b it = “1 ”(d e fa u lt)
D ig ita l A tte n u a to r L e ve l : -8 d B
B a ss B o o st L e ve l : M id d le
D e-em phases response : O F F
S o ft M u te T im e : 1 0 2 4 /fs
(1 ) A d d r:05 H , D a ta :0 0H
(2 ) A d d r:0 6H , D a ta 1 9H
(3 ) A d d r:0 C H , D a ta 10 H
(4 ) A d d r:01 H , D a ta 6 1H
(5 ) A d d r:02 H , D a ta 8 0H
(6 ) A d d r:01 H , D a ta 6 7H
P la yb a c k
(7 ) A d d r:0 1H , D a ta 6 1H
(8 ) A d d r:0 2H , D a ta 8 3H
(9 ) A d d r:0 1H , D a ta 6 0H
(1 0 ) A d d r:0 6 H , D a ta 1 1H
Figure 53. 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 : PMDAC bit = “0” → “1”
(5) Power up headphone-amp : HPL bit = HPR bit = “1” → “0”
Output voltage of headphone-amp is still HVSS.
(6) Rise up the common voltage of headphone-amp : 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 1.0µF, the time constant is τr = 100ms(typ), 250ms(max).
(7) Fall down the common voltage of headphone-amp : PMHPL bit = PMHPR bit = “1” → “0”
The rising time after power up Headphone-amp depends on the capacitor value connected with the MUTET
pin. When this capacitor value is 1.0µF, the time constant is τf = 100ms(typ), 250ms(max).
If the power supply is powered off or Headphone-Amp is powered-down before the common voltage goes to
GND, some click noise occurs. It takes 2times of τf that the common voltage goes to GND.
(8) Power down headphone-amp : HPL bit = HPR bit = “0” → “1”
(9) Power down DAC : PMDAC bit = “1” → “0”
(10) Off the low frequency boost level (BST1-0 bits = “00”)
MS0273-E-02
- 70 -
2005/04