ak4368 AKM Semiconductor, Inc., ak4368 Datasheet - Page 30

• Manufacturer Part Number: ak4368
• Description: Dac With Built-in Pll & Hp-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
The power supply voltage for the headphone-amp is supplied from the HVDD pin and is centered on the MUTET voltage.
The headphone-amp output load resistance is 16Ω (min). When the MUTEN bit is “1” at PMHPL=PMHPR= “1”, the
common voltage rises to 0.475 x HVDD. When the MUTEN bit is “0”, the common voltage of the headphone-amp falls
and the outputs (HPL and HPR pins) go to HVSS.
[Example] : Capacitor between the MUTET pin and ground = 1µF:
When the PMHPL and PMHPR bits are “0”, the headphone-amp is powered-down, and the outputs (HPL and HPR pins)
go to HVSS.
(1) Headphone-amp power-up (PMHPL and PMHPR bits = “1”). The outputs are still at HVSS.
(2) Headphone-amp common voltage rises up (MUTEN bit = “1”). Common voltage of the headphone-amp is rising. This
(3) Headphone-amp common voltage falls down (MUTEN bit = “0”). Common voltage of the headphone-amp is falling
(4) Headphone-amp power-down (PMHPL, PMHPR bits = “0”). The outputs are at HVSS. If the power supply is
MS0529-E-00
Headphone Output (HPL, HPR pins)
rise time depends on the capacitor value connected with the MUTET pin. The rise time up to VCOM/2 is t
C(typ) when the capacitor value on MUTET pin is “C”.
to HVSS. This fall time depends on the capacitor value connected with the MUTET pin. The fall time down to
VCOM/2 is t
switched off or the headphone-amp is powered-down before the common voltage goes to HVSS, some pop noise may
occur.
Rise time up to VCOM/2: t
Fall time down to VCOM/2: t
f
PMHPL/R bit
MUTEN bit
HPL/R pin
= 60k x C(typ) when the capacitor value on MUTET pin is “C”.
t
t
r
f
: Rise Time up to VCOM/2
: Fall Time down to VCOM/2
Figure 21. Power-up/Power-down Timing for the Headphone-Amp
VCOM/2
VCOM
Table 22. Headphone-Amp Rise/Fall Time
r
= 70k x 1µ = 70ms(typ).
(1) (2)
f
= 60k x 1µ = 60ms(typ).
t
r
- 30 -
70k x C (typ)
60k x C (typ)
(3)
t
f
(4)
[AK4368EG]
r
= 70k x
2006/07