Datasheet

CLASS-D SPEAKER DRIVER
SPOM
Class-D
Speaker
Amplifier
26
Class-DGain(R73-D7-D6)
Class-DEnable
(R73-D3)
Gain:
0to+18dB
6dBsteps
LEFT_LOP
S
PVDDL
SPVSSL
25 24
SWOUTP
SWOUTM
29
28
SWINP
SWINM
2730
PowerSupplies
BypassSwitch
(R73-D1)
BypassSwitch
Bootstrap
ClockEnable
(R73-D0)
SPOP
23
+6db
LEFT_LOM
+
-
TLV320AIC3107
SLOS545C – NOVEMBER 2008 – REVISED MARCH 2009 .............................................................................................................................................. www.ti.com
Differential Class-D speaker outputs are available on the SPOP and SPOM pins as shown in Figure 39 . The
integrated Class-D speaker amplifier can drive a one Watt audio signal into a differential 8- Ω load. The plus input
to the Class-D amplifier is the same signal available at the left lineout LEFT_LOP pin. The minus input to the
Class-D amplifier is an internal signal that is sourced as shown in Figure 32 . A register (73) is used to enable the
Class-D amp and set its gain control (0 dB to +18 dB). Following the gain control and before the outputs is a
fixed +6 dB gain. Note that there are many other gains available in the signal path leading up to the Class-D amp
so for best results the user must map the gains correctly.
The following initialization sequence must be written to the AIC3107 registers prior to enabling the class-D
amplifier:
register data:
1. 0x00 0x0D
2. 0x0D 0x0D
3. 0x08 0x5C
4. 0x08 0x5D
5. 0x08 0x5C
6. 0x00 0x00
Also available is an analog bypass switch to allow a signal (0.35V to 2.8V) to be input at SWINP and SWINM
and output at SWOUTP and SWOUTM. In a typical application, SWOUTP and SWOUTM are connected to
SPOP and SPOM respectively so as to provide an alternate method of driving the 8- Ω speaker. These bypass
switches have low on-resistance, so an external power amplifier can be used to drive a speaker directly through
these switches. When the Bypass Switch is enabled (Register 76, D1=1), enabling the Bypass Switch Bootstrap
Clock (Register 76, D0=1) is recommended.
Figure 39. Differential Class-D Speaker Circuit
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