TS4621ML STMICROELECTRONICS [STMicroelectronics], TS4621ML Datasheet - Page 33

• Manufacturer Part Number: TS4621ML
• Description: High-performance class-G stereo headphone amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

TS4621ML
Figure 71. Correct ground connection for single-ended option
Audio driver
VaudioL
Right output
Left output
VaudioR
Vmc
Correct connection location
As shown in
AC ground line of the other input. The AC grounded terminal must be routed in parallel to
the audio signal and grounded with the ground of the audio source.
In this configuration, the AC output voltage is:
Equation 2
Vout = Av x (Vaudio + Vmc) + Vgndnoise x CMRR + Vbatnoise x PSRR
In
50 dB of CMRR and ten millivolts for ground noise gives an output of approximately 30 µV,
which is normally too low to be perceptible in the headphone. If Vmc is also totally controlled
by the design of the audio source,
Equation 3
Vout = Av x Vaudio + Vbatnoise x PSRR
Like in differential mode, the main contributor for audio signal degradation is the AC noise
voltage on Vbat. Thanks to the TS4621ML’s very high PSRR that can attenuate GSM burst
noise,
Equation 4
Vout = Av x Vaudio
Equation 2
Equation 3
Figure
the ground noise is attenuated by the performance of the CMRR. In practice,
becomes:
71, the best option is to route the single-ended signal in parallel with the
Vgndnoise
Cin
1 µF
Cin
1 µF
Cin
1 µF
Cin
1 µF
InL+
InL-
InR+
InR-
Doc ID 023181 Rev 1
Equation 2
2.2 µF
Cs
2.2 µF
Css
PVss
-
+
-
+
Negative
supply
AVdd
C1
becomes:
Vbat
Positive
detector
detector
C12
2.2 µF
supply
Level
Level
C2
Sw
HpVdd
AGnd
VoutR
VoutL
L1
3.3 µH
CMS
Application information
Ct
10 µF
12 ohms min.
12 ohms min.
Rout
Rout
3
2
1
Cout
0.8 nF min.
Cout
0.8 nF min.
J1
AM06155
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