Tr i path Technol ogy, I nc. - Techni cal I nfor m ati on
49.9K
Ω
R
IN
V5
2.2uF, 50V
+
C
IN
1M
Ω
1M
Ω
Input to TA3020
(DC Bias ~2.5V)
10K
Ω
0.1uF, 50V
Figure 5
The value of the input capacitor, C
IN
, in Figure 5 (labeled C100 and C200 on the schematic), and the input
resistor, R
IN
(labeled R100 and R200), set the –3dB point of the input high-pass filter. The frequency of
the input high pass pole, F
P
, –3dB point can be calculated as follows:
F
P
= 1/(2π x C
IN
x R
IN
)
where: C
IN
= input capacitor value in Farads
R
IN
= input resistor value in Ohms
Output offset voltages can be nulled by adjusting the 10KΩ potentiometer shown in Figure 5. Once set,
the offset does not typically drift with temperature, so no tracking circuitry is required. Offsets can
typically be set to +/- 25 mV. R104 is used to adjust the offset of CH1, and R204 is used to adjust the
offset of CH2. If a different TA3020 is placed in the RB-TA3020 reference board, the offset of each
channel will need to be re-trimmed.
RB-TA3020 Control Circuitry
The MUTE pin is brought out to an external 2-pin header, J4 (Figure 6). When a jumper is installed from
Pin 1 to 2 of J4, the MUTE line is pulled to ground and the outputs are enabled. Note that if the MUTE
jumper is removed, the MUTE pin floats high, and the amplifier is muted.
R
OCR
OCR2
J4
MUTE
24
+5V
R111
BBM0
22
33
J2
C103
31
R211
23
+5V
BBM1
J3
AGND
OCR1
C203
Figure 6
6
RB-TA3020, Rev. 3.0/03.02
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
