AK4953A Datasheet, PDF (57/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/HP/SPK-AMP

[AK4953A]
< Speaker-Amp Control Sequence >
The speaker amplifier is powered-up/down by PMSPK bit. When PMSPK bit is “0”, both SPP and SPN pins are in Hi-Z
state. When PMSPK bit is “1” and SPPSN bit is “0”, the speaker amplifier enters power-save mode. In this mode, the SPP
pin is placed in Hi-Z state and the SPN pin outputs SVDD/2 voltage.
When the PMSPK bit is “1” after the PDN pin is changed from “L” to “H”, the SPP and SPN pins rise up from
power-save-mode. In this mode, the SPP pin is placed in a Hi-Z state and the SPN pin goes to SVDD/2 voltage. Because
the SPP and SPN pins rise up at power-save-mode, this mode can reduce a pop noise. When the AK4953A is
powered-down, pop noise can also be reduced by first entering power-save-mode.
PMSPK
0
1
SPPSN
x
0
1
Mode
SPP
SPN
Power-down
Hi-Z
Hi-Z
Power-save
Hi-Z
SVDD/2
Normal Operation Normal Operation Normal Operation
Table 56 Speaker-Amp Mode Setting (x: Don’t care)
(default)
PMSPK bit
SPPSN bit
>1ms _{(Note 51)}
SPP pin
Hi-Z
Hi-Z
SPN pin Hi-Z ^SVDD/2
SVDD/2
Hi-Z
Note 51. This time needs 15ms or more in low voltage mode (LSV bit= “1”).
Figure 39. Power-up/Power-down Timing for Speaker-Amp
■ 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”.
When the internal temperature goes down and the thermal shutdown is released, the charge pump, speaker and headphone
amplifiers are powered up automatically and THDET bit returns to “0”.
MS1252-E-00
- 57 -
2010/10