AK4213 Datasheet, PDF (23/38 Pages) Asahi Kasei Microsystems – Mono Class-D SPK-Amp with Stereo Cap-less HP-Amp

[AK4213]
■ Transition Time
The mute ON/OFF time of headphone-amp is set to PTS1-0 bits. These operations are soft transition.
The Enable/Disable for the soft transition is set by MOFF bit. The soft transition is disabled while MOFF bit is “1”, the
mute ON/OFF is switched immediately.
As shown in Table 15, if the soft transition is enabled, the register value of the same address must be changed in an
interval more than transition time. The write operation is ignored if the same values are written as the previous write
operation.
PTS1-0 bits
Address Register Name
Enable / Disable
0DH
HPMTN bit
MOFF bit
Table 15. Registers with Transition Time
PTS1
PTS0
MUTE ON/OFF Time
typ.
max.
0
0
16.4ms
26.3ms
0
1
32.8ms
51.5ms
1
0
65.6ms
105.0ms
1
1
131.2ms
210.0ms
Table 16. Headphone-Amp Mute ON/OFF Transition Time
(default)
■ Thermal Shutdown Function
When the internal device temperature rises up irregularly (E.g. Output pins of speaker amplifier are shortened.), the
charge pump, headphone amplifier, and speaker amplifier are automatically powered-down and then THDET bit becomes
“1”. The powered-down charge pump circuit, headphone amplifier and speaker amplifier do not return to normal
operation unless HP/SPK-Amp blocks of the AK4213 are reset by the PDN pin “L”. The device status can be monitored
by THDET bit.
<Recommend sequence>
1. VCOM Power-Up; PMVCM bit = “0” Æ “1”
2. Wait more than 1ms
3. Bypass Mode Enable: BYPE bit = “0” Æ “1”
4. Bypass Mode Disable: BYPE bit = “1” Æ “0”
5. VCOM Power-down; PMVCM bit = “1” Æ “0”
■ System Reset
The PDN pin must keep “L” until all power supply pins (AVDD, PVDD, SVDD and TVDD) are supplied. After they are
applied, the PDN pin must be set to “H”. After exiting reset (PDN pin: “L” Æ “H”), all blocks (Input Volume, VCOM,
Oscillator, Mixer, Headphone-Amp, Speaker-Amp and charge pump circuit) switch to the power-down state. The
contents of the control register are maintained until reset is executed.
MS0949-E-01
- 23 -
2008/07