Schematic
4-5
EVM Circuit and Layout
The TPA6120A2 EVM uses 4.02-k
Ω
resistors to tie the positive terminals to
ground. This value is a good compromise between the device’s effect on the
performance of the audio source and the output offset voltage. When the
source is removed or is off (or high impedance), the maximum output offset
value possible with a 4.02-k
Ω
resistor is about 85 mV. The loading effect on
the audio source is minimal since for most sources, a 4.02-k
Ω
load is seen as
high impedance. Going from 4.02 k
Ω
to 10 k
Ω
results in a minimal
performance increase, but pushes the output offset voltage past the 100-mV
threshold.
4.5
Schematic
Figure 4−3. TPA6120A2 EVM Schematic
TPA6120A2
LVCC−
LOUT
LVCC+
LIN+
LIN−
RVCC−
ROUT
RVCC+
RIN+
RIN−
R3
1 k
W
C1
0.1
m
F
R13
DNP
C3
0.1
m
F
R9
4.02 k
W
R4
1 k
W
R14
DNP
R5 10
W
R10
4.02 k
W
C4
0.1
m
F
R6 10
W
R15
DNP
R16
DNP
R7
49.9
W
R1 1 k
W
C2
0.1
m
F
C6
10
m
F
C8
100
m
F
L2
Ferrite
−12 V
To J10
ROUT
RIN+
R8
49.9
W
R2 1 k
W
J6
RIN−
J4
R12
+12 V
C5
10
m
F
C7
100
m
F
L1
Ferrite
To J10
LOUT
LIN+
J5
LIN−
J3
J1
J2
J7
0.01
W
R11
0.01
W
J8
J9
