
AS3515 V15
austriamicrosystems
Data Sheet, Confidential
www.austriamicrosystems.com
Revision 3.1
13
- 66
6.3
Speaker Output
6.3.1
General
The speaker output is designed to provide the stereo audio signal with 2x500mW @ 4
Ω.
This output stage has an independent gain regulation for left and right channel with 32 steps @ 1.5dB each. The gain can be set from
40.5dB to +6dB. The maximum output power of 500mW @ 4Ω is achieved, by setting the mixer output to 1Vp and using the gain of
+6dB.
Figure 4 Speaker Output
6.3.2
No-Pop Function
BGND pin, which needs a 100nF capacitor outside, gets charged on power-up to BVDD/2.To avoiding click and pop noise during power-
up and shutdown, the output is automatically set to mute when the output stage is disabled.
The Start-up time before releasing mute is about 100ms. To avoid pop-noise the 150ms discharging time of SPR / SPL after a shutdown
(220F capacitor in stereo single ended mode assumed), have to be waited before starting up again.
6.3.3
Over-current Protection
This output stage has an over-current protection, which disables the output for 0 to 512ms. This value can be set in the speaker registers.
The over-current protection limit of SPR and SPL pin is typical 700mA. To get an interrupt on an over-current event, the corresponding bit
in the IRQ_ENRD1 register (0x26h) has to be set.
6.3.4
Power Save Options
When driving > 4
Ω, two power save options can be chosen.
The output driver stage can be set to only 25% drive capacity, which will reduce the maximum output power. Additionally the bias currents
can be reduced to 50% in 3 steps.
Table 11 Speaker Power-Save Options
LSP_LP
IBR_LSP IDD_HPH (typ.)
Load
0
00
8mA
4 Ohm
1
00
2.8mA
16-32 Ohm
1
01
2.4mA
16-32 Ohm
1
10
1.9mA
16-32 Ohm
1
11
1.5mA
16-32 Ohm
BVDD = 3.3V, TA= 25oC unless otherwise mentioned
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