T E C H N I C A L I N F O R M A T I O N
External Components Description (Refer to the Application/Test Circuit)
Components Description
RI
RF
CI
Inverting input resistance to provide AC gain in conjunction with RF. This input is
biased at the BIASCAP voltage (approximately 2.5VDC).
Feedback resistor to set AC gain in conjunction with RI. Please refer to the Amplifier
Gain paragraph, in the Application Information section.
AC input coupling capacitor which, in conjunction with RI, forms a highpass filter at
.
fC = 1 (2πRICI)
RFBA
RFBB
Feedback divider resistor connected to V5. This resistor is normally set at 1kΩ.
Feedback divider resistor connected to AGND. This value of this resistor depends
on the supply voltage setting and helps set the TA3020 gain in conjunction with RI,
RF, RFBA, and RFBC. Please see the Modulator Feedback Design paragraphs in the
Application Information Section.
RFBC
Feedback resistor connected from either the OUT1(OUT2) to FBKOUT1(FBKOUT2)
or speaker ground to FBKGND1(FBKGND2). The value of this resistor depends on
the supply voltage setting and helps set the TA3020 gain in conjunction with RI, RF,
RFBA,, and RFBB. It should be noted that the resistor from OUT1(OUT2) to
P
= VPP2 (2RFBC
.
)
FBKOUT1(FBKOUT2) must have a power rating of greater than
DISS
Please see the Modulator Feedback Design paragraphs in the Application
Information Section.
CFB
Feedback delay capacitor that both lowers the idle switching frequency and filters
very high frequency noise from the feedback signal, which improves amplifier
performance. The value of CFB should be offset between channel 1 and channel 2
so that the idle switching difference is greater than 40kHz. Please refer to the
Application / Test Circuit.
ROFA
ROFB
Potentiometer used to manually trim the DC offset on the output of the TA3020.
Resistor that limits the manual DC offset trim range and allows for more precise
adjustment.
RREF
CA
Bias resistor. Locate close to pin 32 and ground at pin 28.
BIASCAP decoupling capacitor. Should be located close to pin 19 and grounded at
pin 28.
DB
Bootstrap diode. This diode charges up the bootstrap capacitors when the output is
low (at VNN) to drive the high side gate circuitry. A fast or ultra fast recovery diode
is recommended for the bootstrap circuitry. In addition, the bootstrap diode must be
able to sustain the entire VPP-VNN voltage. Thus, for most applications, a 150V (or
greater) diode should be used.
CB
High frequency bootstrap capacitor, which filters the high side gate drive supply.
This capacitor must be located as close to pin 40 (VBOOT1) or pin10 (VBOOT2) for
reliable operation. The “negative” side of CB should be connected directly to the
HO1COM (pin 46) or HO2COM (pin 4). Please refer to the Application / Test Circuit.
Bulk bootstrap capacitor that supplements CB during “clipping” events, which result
in a reduction in the average switching frequency.
CBAUX
RB
Bootstrap resistor that limits CBAUX charging current during TA3020 power up
(bootstrap supply charging).
CSW
CS
VN10 generator filter capacitors. The high frequency capacitor (0.1uF) must be
located close to pin 1 (VN10) to maximize device performance.
Supply decoupling for the power supply pins. For optimum performance, these
components should be located close to the TA3020 and returned to their respective
8
TA3020, Rev 2.1, 01.01
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
