ASAHI KASEI

[AK4342]

MS0506-E-02

2006/07

- 23 -

Headphone Output

Power supply voltage for headphone amplifiers is applied from HVDD and HVEE pins. HVEE pin must be connected

with PVEE pin directly. PVEE pin outputs the negative voltage generated by the internal charge pump circuit. The

headphone amplifier is single-ended outputs and centered on 0V(HVSS). Therefore, the capacitor for AC-coupling can be

removed. The minimum load resistance is 16

Ω.

1. Analog output volume

These volumes are channel independent can gain/attenuate the DAC output signal from +6dB to –48dB. (See Table 10)

Changing levels don’t have any pop noise. The transition time is selected by PTS1-0 bits and sampling frequency (See

Table 2 and Table 15).

At PGAC bit = “1”, PGAL4-0 bits control both Lch and Rch attenuation level, while register values of PGAL4-0 bits are

not written to PGAR4-0 bits. At PGAC bit = “0”, PGAL4-0 bits control Lch level and PGAR4-0 bits control Rch level.

When PGAC bit is changed, the transition of volume is executed via soft changes, and PGAL4-0 and PGAR4-0 bits

should be changed after the transition time passes.

When changing PGAC bit = “0”

“1” (In case of “PGAL4-0 bit

≠ PGAR4-0 bit”), the gain of right channel is changed

to the register setting of PGAL4-0 bits. When changing PGAC bit = “1”

“0” (In case of “PGAL4-0 bit

≠ PGAR4-0

bit”), the gain of right channel is changed to the last register setting which is written into PGAR4-0 bits.

PGAL4-0 bits

PGAR4-0 bits

GAIN/ATT (dB)

Step

Level

1FH

+6

1EH

+5

•

•

1AH

+1

19H

0

Default

18H

-1

•

•

10H

-9

1dB

16

0FH

-10

0EH

-12

•

•

06H

-28

05H

-30

2dB

11

04H

-32

03H

-36

02H

-40

01H

-44

00H

-48

4dB

5

Table 10. Volume Setting for headphone amplifier

2. Mute Function

When HMUTEL/HMUTER bit is set to “1”, the headphone amplifier (HPL/HPR pins) goes to ground level (0V). This

function is independent L/R channels. This mute time depends on the setting of PTS1-0 bits and sampling

frequency(FS3-0 bits). When HMUTEL/HMUTER bit is set to “0”, the outputs are in normal operation.

3. Power-up/down

Headphone amplifiers are powered-up/down by PMHP bit, HPL and HPR pins go to HVSS(0V). The power-on/off time

depends on the setting of PUT1-0 bits and sampling frequency (FS3-0 bits). The power-up/down of headphone amplifiers

should be done in the mute state (HMUTEL bit = HMUTER bit = “1”).