ak4538 AKM Semiconductor, Inc., ak4538 Datasheet - Page 34

• Manufacturer Part Number: ak4538
• Description: 16bit ?? Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
n Speaker Output
Mono signal [(L+R)/2] converted from stereo DAC output and BEEP input signal can be output via Speaker-amp which is
controlled by BTL. ALC2 circuit is available for DAC output signal. This Speaker-amp can deliver a maximum power of
300mW(typ)@THD=10%, 250mW(typ)@THD=0.1% into 8 ohm load at HVDD=3.3V. Maximum output power is
137mW(typ) when DAC output signal is output via ALC2 circuit as system design example (Figure 46). When BEEP input
is used for DAC output, maximum power becomes 300mW. Figure 29 and Figure 30 indicates connection examples for
300mW output.
Speaker blocks (MOUT2, ALC2 and Speaker-amp) can be powered up/down by controlling the PMSPK bit. When the
PMSPK bit is “0”, the MOUT2, SPP and SPN pins are placed in a Hi-Z state.
When the SPPS bit is “0”, the Speaker-amp enters power-save-mode. In this mode, the SPP pin is placed in a Hi-Z state and
the SPN pin goes to HVDD/2 voltage. And then the Speaker output gradually changes to the HVDD/2 voltage and this
mode can reduce pop noise at power-up. When the AK4538 is powered down, pop noise can be also reduced by first
entering power-save-mode.
[Connection Example for 300mW output]
MS0198-E-01
(1) Using BEEPM pin
PMSPK bit
SPPS bit
SPP pin
SPN pin
MOUT2
AK4538
Hi-Z
Figure 29. Connection example for 300mW output using BEEPM pin
0.047u
Figure 28. Power-up/Power-down Timing for Speaker-amp
HVDD/2
Hi-Z
13k
BEEPM
45%AVDD
- 34 -
20k
30%
BPMSP
SPK-Amp
HVDD/2
SPP
SPN
Hi-Z
Hi-Z
[AK4538]
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