Tripath Technology, Inc. - Technical Information
1 TA2020 – KLI/1.0/11-01
TA2022
STEREO 90W (4Ω) CLASS-T™ DIGITAL AUDIO AMPLIFIER
DRIVER USING DIGITAL POWER PROCESSING (DPP™)
TECHNOLOGY
Technical Information Revision 1.0 – November 2001
GENERAL DESCRIPTION
The TA2022 is a 90W (4Ω) continuous average per channel Class-T Digital Audio
Power Amplifier IC using Tripath’s proprietary Digital Power Processing (DPPTM)
technology. Class-T amplifiers offer both the audio fidelity of Class-AB and the
power efficiency of Class-D amplifiers.
APPLICATIONS
DVD Players
Mini/Micro Component Systems
Home Theater
Powered Speakers
BENEFITS
Fully integrated solution with internal
FETs
Dramatically improves efficiency versus
Class-AB amplifiers
Signal fidelity equal to high quality linear
amplifiers
High dynamic range compatible with
digital media such as CD and DVD
FEATURES
Class-T architecture
High Power
100W @ 4Ω, 1.0% THD+N
90W @ 4Ω, 0.1% THD+N
60W @ 8Ω, 0.1% THD+N
“Audiophile” Sound Quality
0.015% THD+N @ 70W 4Ω
0.015% THD+N @ 45W 8Ω
0.10% IHF-IM @ 25W 4Ω
High Efficiency
92% @ 88W 8Ω
87% @ 125W 4Ω
Dynamic Range = 102 dB
Mute Input
Integrated Gate Drive Supply
Over-current protection
Over and under-voltage protection
Single ended outputs
Outputs can be operated in bridged mode
32-pin SSIP package
Tripath Technology, Inc. - Technical Information
2 TA2020 – KLI/1.0/11-01
ABSOLUTE MAXIMUM RATINGS (Note 1)
SYMBOL PARAMETER Value UNITS
VPP, VNN Supply Voltage (VPP1, VPP2, VNN1, VNN2) +/- 40 V
V5 Positive 5V Bias Supply
Voltage at Input Pins (pins 18, 19, 23, 24, 26, 28-32)
6
-0.3V to (V5+0.3V)
V
V
VN10 Voltage for low-side FET drive VNN+13 V
TSTORE Storage Temperature Range -55º to 150º C
TA Operating Free-air Temperature Range (Note 2) -40º to 85º C
TJ Junction Temperature 150º C
ESDHB ESD Susceptibility – Human Body Model (Note 3)
All pins (except pin 27)
Pin 27
4000
1500
V
V
ESDMM ESD Susceptibility – Machine Model (Note 4)
All pins
200
V
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.
See the table below for Operating Conditions.
Note 2: This is a target specification. Characterization is still needed to validate this temperature range.
Note 3: Human body model, 100pF discharged through a 1.5KΩ resistor.
Note 4: Machine model, 220pF – 240pF discharged through all pins.
OPERATING CONDITIONS (Note 5)
SYMBOL PARAMETER MIN. TYP. MAX. UNITS
VPP, VNN Supply Voltage (VPP1, VPP2, VNN1, VNN2) +/- 12 +/-31 +/- 36 V
V5 Positive 5 V Bias Supply 4.5 5 5.5 V
VN10 Voltage for FET drive (Volts above VNN) 9 11 12 V
Note 5: Recommended Operating Conditions indicate conditions for which the device is functional.
See Electrical Characteristics for guaranteed specific performance limits.
THERMAL CHARACTERISTICS
SYMBOL PARAMETER VALUE UNITS
θJC Junction-to-case Thermal Resistance 1.0° C/W
θJA Junction-to-ambient Thermal Resistance (still air) 20° C/W
Tripath Technology, Inc. - Technical Information
3 TA2020 – KLI/1.0/11-01
ELECTRICAL CHARACTERISTICS (Notes 6, 7)
TA = 25 °C. See Application/Test Circuit on page 8. Unless otherwise noted, the supply voltage is
VPP=|VNN|=31V.
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS
Iq Quiescent Current
(No load, Mute = 0V)
VPP = +31V
VNN = -31V (Note 8)
V5 = 5V (Note 9)
VN10 = 11V (Note 10)
20
55
45
65
60
80
mA
mA
mA
mA
IMUTE Mute Supply Current
(No load, Mute = 5V)
VPP = +31V
VNN = -31V (Note 8)
V5 = 5V (Note 9)
0.5
2
20
25
mA
mA
mA
VIH High-level input voltage (MUTE) IIH = See Mute Control Section 3.5 V
VIL Low-level input voltage (MUTE) IIL = See Mute Control Section 1.0 V
VOH High-level output voltage (HMUTE) IOH = 3mA 4.0 V
VOL Low-level output voltage (HMUTE) IOL = 3mA 0.5 V
VOFFSET Output Offset Voltage No Load, MUTE = Logic low
0.1% RFBA, RFBB, RFBC resistors
-750 750 mV
IOC Over Current Sense Threshold TBD 7 8 A
IVPPSENSE VPPSENSE Threshold Currents
Over-voltage turn on (muted)
Over-voltage turn off (mute off)
Under-voltage turn off (mute off)
Under-voltage turn on (muted)
138
62
162
154
79
72
178
87
µA
µA
µA
µA
VVPPSENSE Threshold Voltages with
RVPPSENSE = 249KΩ
(Note 11, Note 12)
Over-voltage turn on (muted)
Over-voltage turn off (mute off)
Under-voltage turn off (mute off)
Under-voltage turn on (muted)
36.5
17.8
42.8
40.9
22.2
20.4
47.3
24.4
V
V
V
V
IVNNSENSE VNNSENSE Threshold Currents
Over-voltage turn on (muted)
Over-voltage turn off (mute off)
Under-voltage turn off (mute off)
Under-voltage turn on (muted)
152
65
174
169
86
77
191
95
µA
µA
µA
µA
VVNNSENSE Threshold Voltages with
RVNNSENSE = 249KΩ
(Note 11, Note 12)
Over-voltage turn on (muted)
Over-voltage turn off (mute off)
Under-voltage turn off (mute off)
Under-voltage turn on (muted)
-36.2
-14.8
-42.1
-40.8
-20.2
-17.9
-46.8
-22.6
V
V
V
V
Tripath Technology, Inc. - Technical Information
4 TA2020 – KLI/1.0/11-01
PERFORMANCE CHARACTERISTICS – SINGLE ENDED (Notes 6, 7)
TA = 25 °C. Unless otherwise noted, the supply voltage is VPP=|VNN|=31V, the input frequency
is 1kHz and the measurement bandwidth is 20kHz. See Application/Test Circuit on Page 8.
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS
POUT Output Power
(Continuous Average/Channel)
(Note 13)
VPP = |VNN| = +/-31V, RL = 4Ω
THD+N = 0.1%
THD+N = 1.0%
THD+N = 10%
VPP = |VNN| = +/-35V, RL = 8Ω
THD+N = 0.1%
THD+N = 10%
80
90
100
125
60
88
W
W
W
W
THD + N Total Harmonic Distortion Plus
Noise
POUT = 70W/Channel, RL = 4Ω
VPP = |VNN| = +/-31V
POUT = 45W/Channel, RL = 8Ω
VPP = |VNN| = +/-35V
0.015
0.015
%
%
IHF-IM IHF Intermodulation Distortion 19kHz, 20kHz, 1:1 (IHF), RL = 4Ω
POUT = 25W/Channel
0.1 %
SNR Signal-to-Noise Ratio A-Weighted
0dB = 90W/Channel, RL = 4Ω
102 dB
CS Channel Separation 0dB = 25W, RL = 4Ω 83 dB
AV Amplifier Gain POUT = 10W/Channel, RL = 4Ω,
See Application / Test Circuit
18.1 V/V
AVERROR Channel to Channel Gain Error POUT = 10W/Channel, RL = 4Ω
See Application / Test Circuit
0.5 dB
η Power Efficiency POUT = 88W/Channel, RL = 8Ω
POUT = 125W/Channel, RL = 4Ω
92
87
%
%
ISLOAD Source Current POUT = 125W/Channel, RL = 4Ω
VPP = +31V
VNN = -31V
V5 = 5V
4.59
4.61
45
A
A
mA
eNOUT Output Noise Voltage A-Weighted, input AC grounded 150 µV
PERFORMANCE CHARACTERISTICS – BRIDGED TIED LOAD (Notes 6, 7)
TA = 25 °C. Unless otherwise noted, the supply voltage is VPP=|VNN|=30V, the input frequency
is 1kHz and the measurement bandwidth is 20kHz.
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS
POUT Output Power
(Continuous Average)
(Note 13)
VPP = |VNN| = +/-30V, RL = 8Ω
THD+N = 0.1%
THD+N = 10%
150
235
W
W
THD + N Total Harmonic Distortion Plus
Noise
POUT = 100W, RL = 8Ω 0.05 %
IHF-IM IHF Intermodulation Distortion 19kHz, 20kHz, 1:1 (IHF), RL = 8Ω
POUT = 25W
0.10 %
η Power Efficiency POUT = 225W, RL = 8Ω 87 %
SNR Signal-to-Noise Ratio A-Weighted, RL = 8Ω
0dB = 150W
104 dB
eNOUT Output Noise Voltage A-Weighted, input AC grounded 220 µV
Note 6: Minimum and maximum limits are guaranteed but may not be 100% tested.
Note 7: For operation in ambient temperatures greater than 25°C, the device must be derated
based on the maximum junction temperature and the thermal resistance determined
by the mounting technique.
Tripath Technology, Inc. - Technical Information
5 TA2020 – KLI/1.0/11-01
Note 8: This specification includes the current draw from the internal buck regulator. If an
external floating supply is used, instead of the internal buck regulator, the quiescent
current draw of the VNN supply will be approximately 20mA.
Note 9: This specification includes the current draw from both the TA2022 and the external
feedback biasing.
Note 10: This is the current draw of the VN10 pin if an external “floating” 11V supply is used
instead of the internal buck regulator
Note 11: These supply voltages are calculated using the IVPPSENSE AND IVNNSENSE
values shown in the Electrical Characteristics table. The typical voltage values
shown are calculated using a RVPPSENSE and RVNNSENSE value of 249kohm
without any tolerance variation. The minimum and maximum voltage limits shown
include either a +1% or –1% (+1% for Over-voltage turn on and Under-voltage turn
off, -1% for Over-voltage turn off and Under-voltage turn on) variation of
RVPPSENSE or RVNNSENSE off the nominal 249kohm value. These voltage
specifications are examples to show both typical and worst case voltage ranges for a
given RVPPSENSE and RVNNSENSE resistor value of 249kohm. Please refer to
the Application Information section for a more detailed description of how to calculate
the over and under voltage trip voltages for a given resistor value.
Note 12: The fact that the over-voltage turn on and over-voltage turn off specifications exceed
the absolute maximum of +/-40V for the TA2022 does not imply that the part will work
at these elevated supply voltages. It also does not imply that TA2022 is tested or
guaranteed at these supply voltages. The supply voltages are simply a calculation
based on the process spread of the IVPPSENSE and IVNNSENSE currents (see Note 11).
The supply voltage must be maintained below the absolute maximum of +/-40V or
permanent damage to the TA2022 may occur.
Note 13: The supply voltage limitation for 4 ohm single ended (+/-31V), or 8 ohm bridged (+/-
30V), is based on the current limit protection circuitry. The current limit circuitry may
be activated during large output excursions if the recommended supply voltage
ranges are exceeded.
This will result in the amplifier being muted.
Tripath Technology, Inc. - Technical Information
6 TA2020 – KLI/1.0/11-01
TA2022 PINOUT
PIN DESCRIPTION
Pin Function Description
1, 13 VBOOT2, VBOOT1 Bootstrap voltages for gate drive of high side MOSFET’s
2 VN10 “Floating” supply input. Normally connected to the output of onboard VN10 buck
converter. This voltage must be stable and referenced to VNN.
3 VN10GND Power ground for onboard VN10 generator. Electrically tied to the TA2022 case.
4, 12 VPP2, VPP1 Positive power supply input pins.
5 VN10SW Switching output voltage for onboard VN10 generator (buck converter).
6 NC Not connected internally. May be connected to pin 7 without any loss of
functionality or performance.
7,10 OUT2, OUT1 Power amplifier outputs.
8, 9 VNN2, VNN1 Negative power supply inputs.
11 NC Not connected internally. May be connected to pin 10 without any loss of
functionality or performance.
14 VN10FDBK Feedback for onboard VN10 generator (nominally 11V above VNN)
15, 20 AGND Analog Ground.
16, 21 V5 5V power supply input.
17 REF Used to set internal bias currents. The pin voltage is typically 1.1V.
18 VNNSENSE Negative supply voltage sense input. This pin is used for both over and under
voltage sensing for the VNN supply.
19 VPPSENSE Positive supply voltage sense input. This pin is used for both over and under
voltage sensing for the VPP supply.
22, 25 OAOUT1, OAOUT2 Outputs of Input Stage op amps.
23, 26 INV1, INV2 Inverting inputs of Input Stage op amps.
24 MUTE Logic input. A logic high puts the amplifier in mute mode. Ground pin if not used.
Please refer to the section, Mute Control, in the Application Information.
27 BIASCAP Bandgap reference times two (typically 2.5VDC). Used to set the common mode
voltage for the input op amps. This pin is not capable of driving external circuitry.
28, 29 FBKGND2, FBKOUT2 Output voltage differential feedback for channel 2.
30,31 FBKGND1, FBKOUT1 Output voltage differential feedback for channel 1.
32 HMUTE Logic Output. A logic high indicates both amplifiers are muted, due to the mute
pin state, or a “fault” such as an overcurrent, undervoltage, or overvoltage
condition.
FBKGND1
AGND
VNNSENSE
VPPSENSE
AGND
V5
OAOUT1
INV1
MUTE
OAOUT2
INV2
VBOOT2
BIASCAP
FBKGND2
FBKOUT2
FBKOUT1
V5
VN10FDBK
VBOOT1
VPP1
NC
OUT1
VNN1
VNN2
OUT2
NC
VPP2
VN10GND
VN10
HMUTE
30
16
17
18
19
20
21
22
23
24
25
26
27
28
29
1
15
14
13
11
10
12
9
8
7
6
5
4
3
2
32-pin SSIP Package
(Front View)
32
31
REF
VN10SW
Tripath Technology, Inc. - Technical Information
7 TA2020 – KLI/1.0/11-01
APPLICATION /TEST CIRCUIT
TA2022
RL
4Ω or 8Ω
HMUTE
OAOUT1
INV1
OUT1
CI
3.3uF
22
23
32
10
+
VPP1
VNN1
Processing
&
Modulation
CO
0.22uF
LO
10uH, 10A
Analog Ground
Power Ground
(Pin 9)
RF
20KΩ
RI
20KΩ
CZ
0.22uF
RZ
6.2Ω, 2W
CB
0.1uF
CBAUX
47uF
VBOOT1
13 RB 250Ω
VNN1
VN10
DB
11DQ09 VN10
FBKOUT1
31
FBKGND1
30
RFBA
1KΩ
*RFBB
1.1KΩ
*RFBB
1.1KΩ
RFBA
1KΩ
DO
MUR120
*RFBC
9.1KΩ
*RFBC
9.1KΩ
V5 (Pin 21)
AGND (Pin 20)
+
V5
AGND
CFB
390pF
CS
0.1uF
CS
0.1uF
21
20
V5
15
AGND
AGND
V5
16
5V
OAOUT2
INV2 OUT2
CI
3.3uF
25
26 7
+
VPP2
VNN2
Processing
&
Modulation CO
0.22uF
LO
10uH, 10A
(Pin 8)
RF
20KΩ
RI
20KΩ
CZ
0.22uF
RZ
6.2Ω, 2W
CB
0.1uF
CBAUX
47uF
VBOOT2
1RB 250Ω
VNN2
VN10
DB
11DQ09
VN10
FBKOUT229
FBKGND2
28
RFBA
1KΩ
*RFBB
1.1KΩ
*RFBB
1.1KΩ
RFBA
1KΩ
DO
MUR120
*RFBC
9.1KΩ
*RFBC
9.1KΩ
V5 (Pin 21)
+
-
+
V5
AGND
CFB
560pF
MUTE 24
5V
V5
BIASCAP
CA
0.1uF 27
17
REF
RREF
8.25KΩ, 1%
12
VPP1
9
VNN1
+
CHBR
0.1uF,100V Cs
220uF, 50V
CS
0.1uF, 50V
+
Cs
220uF, 50V
CS
0.1uF, 50V
8
VNN2
4VPP2
CHBR
0.1uF,100V
VPP
VNN
VN10GND
*RVPPSENSE(VPP1)
VPP
VNN
19 VPPSENSE
18 VNNSENSE
3
VN10
Generator
VNN
AGND (Pin 20)
VN10SW
5
CSWFB
0.1uF,50V
VN10FBK
14
VNN
CSW
0.1uF,35V
VN10
2
VNN
DSW
11DQ09
LSW
100uH, 1A
RSWFB
1KΩ
+CSW
100uF, 35V
VN10
RL
4Ω or 8Ω
2.5V
200KΩ
(Pin 20)
(Pin 20)
(Pin 20)
ROFA
50KΩ
ROFB
10KΩto FBKGND1
(Pin30)
Offset Trim
Circuit
V5 (Pin 21)
AGND (Pin 20)
VNN
249KΩ, 1%
ROFA
50KΩ
ROFB
10KΩto FBKGND2
(Pin28)
Offset Trim
Circuit
V5 (Pin 21)
AGND (Pin 20)
-
+
*RVNNSENSE(VNN1) 249KΩ, 1%
6NC
11 NC
*RVPP2
V5
V5
*RVNN2
Optional Components -
See Application Information
* The values of these components must be
adjusted based on supply voltage range.
See Application Information.
VPP2
(Pin 4) DO
MUR120
VPP1
(Pin 12) DO
MUR120
Application / Test Diagram
CS
0.1uF, 50V
CS
0.1uF, 50V
CS
0.1uF, 50V
CS
0.1uF, 50V
Tripath Technology, Inc. - Technical Information
8 TA2020 – KLI/1.0/11-01
EXTERNAL COMPONENTS DESCRIPTION (Refer to the Application/Test Circuit)
Components Description
RI Inverting input resistance to provide AC gain in conjunction with RF. This input is biased
at the BIASCAP voltage (approximately 2.5VDC).
RF Feedback resistor to set AC gain in conjunction with RI. Please refer to the Amplifier
Gain paragraph, in the Application Information section.
CI AC input coupling capacitor which, in conjunction with RI, forms a high pass filter at
)CR2(1f IIC π= .
RFBA Feedback divider resistor connected to V5. This resistor is normally set at 1kΩ.
RFBB Feedback divider resistor connected to AGND. This value of this resistor depends on
the supply voltage setting and helps set the TA2022 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 TA2022 gain in conjunction with RI, RF, RFBA,, and
RFBB. It should be noted that the resistor from OUT1(OUT2) to FBKOUT1(FBKOUT2)
must have a power rating of greater than )(2RVPPP FBC
2
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 Potentiometer used to manually trim the DC offset on the output of the TA2022.
ROFB Resistor that limits the manual DC offset trim range and allows for more precise
adjustment.
RREF Bias resistor. Locate close to pin 17 and ground at pin 20.
CA BIASCAP decoupling capacitor. Should be located close to pin 27 and grounded at pin 20.
DB Bootstrap diode. This diode charges up the bootstrap capacitors when the output is low
(at VNN) to drive the high side gate circuitry. Schottky or fast recovery diode rated at
least 200mA, 90V, 50nS 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 90V (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 13 (VBOOT1) or pin1n (VBOOT2) for reliable
operation. The other side of CB should be connected directly to the OUT1 (pin 10) or
OUT2 (pin 7). Please refer to the Application / Test Circuit.
CBAUX Bulk bootstrap capacitor that supplements CB during “clipping” events, which result in a
reduction in the average switching frequency.
RB Bootstrap resistor that limits CBAUX charging current during TA2022 power up (bootstrap
supply charging).
CSW VN10 generator filter capacitors. The high frequency capacitor (0.1uF) must be located
close to pin 2 (VN10) to maximize device performance. The value of the bulk capacitor
should be sized appropriately such that the VN10 voltage does not overshoot with
respect to VNN during TA2022 turn on. Tripath recommends using a value of 100F for
the bulk capacitor.
LSW VN10
g
enerator filter inductor. This inductor sized a
pp
ro
p
riatel
y
so that L
S
W does not
Tripath Technology, Inc. - Technical Information
9 TA2020 – KLI/1.0/11-01
saturate. If the recommended inductor value of 100H is not used, the VN10 may
overshoot with respect to VNN during TA2022 turn on.
DSW Flywheel diode for the internal VN10 buck converter. This diode also prevents VN10SW
from going more than one diode drop negative with respect to VNN. This Diode can be a
Fast Recovery, Switching or Shottky, but must be rated at least 200mA, 30V, 50nS.
CSWFB VN10 generator feedback capacitor. This capacitor, in conjunction with RSWFB, filters the
VN10 feedback signal such that the loop is unconditionally stable.
RSWFB VN10 generator feedback resistor. This resistor sets the nominal VN10 voltage. With
RSWFB equal to 1kΩ, the internally VN10 voltage will typically be 11V above VNN.
CS Supply decoupling for the power supply pins. For optimum performance, these
components should be located close to the TA2022 and returned to their respective
ground as shown in the Application/Test Circuit.
RVNNSNESE Overvoltage and undervoltage sense resistor for the negative supply (VNN). Please
refer to the Electrical Characteristics Section for the trip points as well as the hysteresis
band. Also, please refer to the Over / Under-voltage Protection section in the Application
Information for a detailed discussion of the internal circuit operation and external
component selection.
RVPPSENSE Overvoltage and undervoltage sense resistor for the positive supply (VPP). Please refer
to the Electrical Characteristics Section for the trip points as well as the hysteresis band.
Also, please refer to the Over / Under-voltage Protection section in the Application
Information for a detailed discussion of the internal circuit operation and external
component selection.
CHBR Supply decoupling for the high current Half-bridge supply pins. These components must
be located as close to the device as possible to minimize supply overshoot and
maximize device reliability. These capacitors should have good high frequency
performance including low ESR and low ESL. In addition, the capacitor voltage rating
must be twice the maximum VPP voltage.
CZ Zobel capacitor, which in conjunction with RZ, terminates the output filter at high
frequencies. Use a high quality film capacitor capable of sustaining the ripple current
caused by the switching outputs.
RZ Zobel resistor, which in conjunction with CZ, terminates the output filter at high
frequencies. The combination of RZ and CZ minimizes peaking of the output filter under
both no load conditions or with real world loads, including loudspeakers which usually
exhibit a rising impedance with increasing frequency. The recommended power rating is
2 watts.
DO Fast Recovery diodes that minimize overshoots and undershoots of the outputs with respect
to power ground during switching transitions as well as output shorts to ground. For
maximum effectiveness, these diodes must be located close to the output pins and returned
to their respective VPP and VNN. Also, they should be rated with a maximum Forward
Voltage of 1V at 10A. Please see Application/Test Circuit for VPP and VNN return pins.
LO Output inductor, which in conjunction with CO, demodulates (filters) the switching
waveform into an audio signal. Forms a second order filter with a cutoff frequency
of )CL2(1f OOC π= and a quality factor of OOOL CLCRQ =. These
inductors must be rated at least 10A with high linearity. Please see Output Filter
Design section for details.
CO
Output capacitor, which, in conjunction with LO, demodulates (filters) the switching
waveform into an audio signal. Forms a second order low-pass filter with a cutoff
frequency of )CL2(1f OOC π= and a quality factor of OOOL CLCRQ =. Use a
high quality film capacitor capable of sustaining the ripple current caused by the
switching outputs. Electrolytic capacitors should not be used.
Tripath Technology, Inc. - Technical Information
10 TA2020 – KLI/1.0/11-01
TYPICAL PERFORMANCE CHARACTERISTICS – SINGLE ENDED
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
2100510 20 50
Output Power (W)
THD+N (%)
THD+N vs Output Power
f = 1kHz
RL= 8Ω
VPP=|VNN|=35V
AES 17 Filter
1
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
THD+N (%)
THD+N vs Frequency
Po = 25W/ch
RL = 8Ω
VPP=|VNN|=35V
BW = 22kHz
BW = 30kHz
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
THD+N (%)
THD+N vs Frequency
Po = 50W/ch
RL = 4Ω
VPP=|VNN|=31V
BW = 22kHz
BW = 30kHz
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
12002 5 10 20 50 100
Output Power (W)
THD+N (%)
THD+N vs Output Power
f = 1kHz
RL= 4Ω
VPP=|VNN|=31V
AES 17 Filter
-140
+0
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Amplitude (dBr)
Intermodulation Distortion
19kHz, 20kHz 1:1
Po = 25W/ch, 4Ω
0dBr = 10.0Vrms
VPP=|VNN|=31V
BW = 22Hz - 30kHz
-140
+0
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Amplitude (dBr)
Intermodulation Distortion
19kHz, 20kHz 1:1
Po = 12.5W/ch, 8Ω
0dBr = 10.0Vrms
VPP=|VNN|=31V
BW = 22Hz - 30kHz
Tripath Technology, Inc. - Technical Information
11 TA2020 – KLI/1.0/11-01
TYPICAL PERFORMANCE CHARACTERISTICS – SINGLE ENDED
TY
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
2100510 20 50
Output Power (W)
THD+N (%)
THD+N vs Output Power
f = 1kHz
RL= 8Ω
AES 17 Filter
1
+/-25V
+/-30V
+/-35V
-100
-40
-95
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Channel Separation (dBr)
Channel Separation
VPP=|VNN|=31V
Po = 25W/ch, 4Ω
Po = 12.5W/ch, 8Ω
BW = 22Hz - 22kHz
RL = 8Ω
RL = 4Ω
-120
-70
-115
-110
-105
-100
-95
-90
-85
-80
-75
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Amplitude (dBr)
Noise Floor
VPP=|VNN|=31V
RF=RI=20kΩ
16kFFT
AES 17 Filter
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
12002 5 10 20 50 100
Output Power (W)
THD+N (%)
THD+N vs Output Power
f = 1kHz
RL= 4Ω
AES 17 Filter
+/-23V
+/-27V
+/-31V
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100 110 120
Output Power (W)
Efficiency (%)
VPP=|VNN|=31V
RL = 4Ω
AES 17 Filter
THD+N < 10%
Efficiency vs Output Power
0
10
20
30
40
50
60
70
80
90
100
0 102030405060708090
Output Power (W)
Efficiency (%)
VPP=|VNN|=35V
RL = 8Ω
AES 17 Filter
THD+N < 10%
Efficiency vs Output Power
Tripath Technology, Inc. - Technical Information
12 TA2020 – KLI/1.0/11-01
TYPICAL PERFORMANCE CHARACTERISTICS – BRIDGED
-140
+0
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Amplitude (dBr)
Intermodulation Distortion
19kHz, 20kHz 1:1
Po = 50W/ch, 8Ω BRIDGED
0dBr = 20.0Vrms
VPP=|VNN|=30V
BW = 22Hz - 30kHz
2300510 20 50 100 200
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
Output Power (W)
THD+N (%)
THD+N vs Output Power
f = 1kHz
RL= 8Ω BRIDGED
AES 17 Filter
1
+/-23V
+/-27V
+/-30V
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
THD+N (%)
THD+N vs Frequency
Po = 100W/ch
RL = 8Ω BRIDGED
VPP=|VNN|=30V
BW = 22kHz
BW = 30kHz
-120
-70
-115
-110
-105
-100
-95
-90
-85
-80
-75
20 20k50 100 200 500 1k 2k 5k 10k
Frequency (Hz)
Amplitude (dBr)
Noise Floor
VPP=|VNN|=30V
RF=RI=20kΩ
8Ω BRIDGED
16kFFT
AES 17 Filter
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80 100 120 140 160 180 200 220 240
Output Power (W)
Efficiency (%)
VPP=|VNN|=30V
RL = 8Ω BRIDGED
AES 17 Filter
THD+N < 10%
Efficiency vs Output Power
0.005
10
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
2300510 20 50 100 2001
Output Power (W)
THD+N (%)
f = 1kHz
VPP=|VNN|=30V
RL= 8Ω BRIDGED
AES 17 Filter
THD+N vs Output Power
Tripath Technology, Inc. - Technical Information
13 TA2020 – KLI/1.0/11-01
APPLICATION INFORMATION
TA2022 Basic Amplifier Operation
The TA2022 has three major operational blocks: the signal processor, the MOSFET driver, and the
power MOSFETs. The signal processor is a 5V CMOS block that amplifies the audio input signal and
converts the audio signal to a switching pattern. This switching pattern is spread spectrum with a
typical idle switching frequency of about 650kHz. The switching patterns for the two channels are not
synchronized and the idle switching frequencies should differ by at least 40kHz to avoid increasing
the audio band noise floor. The idle frequency difference can be accomplished by offsetting the value
of CFB for each channel. Typical values of CFB are 390pF for channel 1 and 560pF for channel 2.
The MOSFET driver level-shifts the signal processor’s 5V switching patterns to the power supply
voltages and drives the power MOSFETs. The MOSFET driver includes a switching power supply
integrated to generate the VN10 supply. The VN10 supply powers the low side gate drivers as well
provides the charging current need for the “bootstrapped” supplies (VBOOT1 and VBOOT2) that
power the high side MOSFET drivers. VN10 must be stable (regulated) at 10V to 12V above VNN.
The VN10 circuitry shown in the Application / Test Circuit typically produces 11V above VNN.
The power MOSFETs are N-channel devices configured in half-bridges and are used to supply power
to the output load. The outputs of the power MOSFETs (OUT1 and OUT2) must be low pass filtered
to remove the high frequency switching pattern. A residual voltage from the switching pattern will
remain on the speaker outputs when the recommended output LC filter is used, but this signal is
outside of the audio band and will not affect audio performance.
Circuit Board Layout
The TA2022 is a power (high current) amplifier that operates at relatively high switching frequencies.
The output of the amplifier switches between VPP and VNN at high speeds while driving large
currents. This high-frequency digital signal is passed through an LC low-pass filter to recover the
amplified audio signal. Since the amplifier must drive the inductive LC output filter and speaker loads,
the amplifier outputs can be pulled above the supply voltage and below ground by the energy in the
output inductance. To avoid subjecting the TA2022 to potentially damaging voltage stress, it is critical
to have a good printed circuit board layout. It is recommended that Tripath’s layout and application
circuit be used for all applications and only be deviated from after careful analysis of the effects of any
changes. Please refer to the TA2022 evaluation board document, EB-TA2022, available on the
Tripath website, at www.tripath.com.
The following components are important to place near their associated TA2022 pins and are ranked
in order of layout importance, either for proper device operation or performance considerations.
- The capacitors CHBR provide high frequency bypassing of the amplifier power supplies and
will serve to reduce spikes across the supply rails. CHBR should be kept within 1/8” (3mm)
of the VNN(8,9) and VPP(4,12) pins. Please note that both VNN1 and VPP1 as well as
VNN2 and VPP2 must be decoupled separately. In addition, the voltage rating for CHBR
should be 100V as this capacitor is exposed to the full supply range, VPP-VNN.
- DO, fast recovery PN junction diodes minimize undershoots of the outputs with respect to
power ground during switching transitions and abnormal load conditions such as output
shorts to ground. For maximum effectiveness, these diodes must be located close to the
output pins and returned to their respective VNN1(2). Please see Application/Test Circuit
for ground return pin.
- CFB removes very high frequency components from the amplifier feedback signals and
lowers the output switching frequency by delaying the feedback signals. In addition, the
value of CFB is different for channel 1 and channel 2 to keep the average switching
frequency difference greater than 40kHz. This minimizes in-band audio noise.
Tripath Technology, Inc. - Technical Information
14 TA2020 – KLI/1.0/11-01
- To minimize noise pickup and minimize THD+N, RFBC should be located as close to the
TA2022 as possible. Make sure that the routing of the high voltage feedback lines is kept
far away from the input op amps or significant noise coupling may occur. It is best to shield
the high voltage feedback lines by using a ground plane around these traces as well as the
input section.
- CB provides high frequency bypassing for the bootstrap supplies. Very high currents are
present on these supplies.
- CSW provides high frequency bypassing for the VN10 generator circuit. Very high currents
are present on these supplies.
- CSWFB filters the feedback signal (VN10FDBK) for the hysteretic VN10 buck converter. The
feedback signal is noise sensitive and the trace from CSWFB to VNN should be kept short.
- DSW is the flywheel diode for the VN10 buck converter and prevents VN10SW(pin 5) from
going more than one diode drop below VNN.
In general, to enable placement as close to the TA2022, and minimize PCB parasitics, the capacitors
listed above should be surface mount types, located on the “solder” side of the board.
Some components are not sensitive to location but are very sensitive to layout and trace routing.
- To maximize the damping factor and reduce distortion and noise, the modulator feedback
connections should be routed directly to the pins of the output inductors, LO. This was done
on the EB-TA2022 board.
- The output filter capacitor, CO, and zobel capacitor, CZ, should be star connected with the
load return. The output ground feedback signal should be taken from this star point. This is
suggested by the routing on the Application/Test schematic, but, for space/layout reasons,
this was not fully implemented on the EB-2022.
- The modulator feedback resistors, RFBA and RFBB should all be grounded and attached to
5V together. These connections will serve to minimize common mode noise via the
differential feedback. Please refer to the EB-TA2022 evaluation board for more information.
TA2022 Grounding
Proper grounding techniques are required to maximize TA2022 functionality and performance.
Parametric parameters such as THD+N, Noise Floor and crosstalk can be adversely affected if proper
grounding techniques are not implemented on the PCB layout. The following discussion highlights
some recommendations about grounding both with respect to the TA2022 as well as general “audio
system” design rules.
The TA2022 is divided into two sections: the input section, which spans pin 15 through pin 32, and
the output (high power) section, which spans pin 1 through pin 14. On the TA2022 evaluation board,
the ground is also divided into distinct sections, one for the input and one for the output. To minimize
ground loops and keep the audio noise floor as low as possible, the input and output ground must be
only connected at a single point. Depending on the system design, the single point connection may
be in the form of a ferrite bead or a PCB trace.
The analog grounds, pin 15 and pin 20 must be connected locally at the TA2022 for proper device
functionality. On the TA2022 evaluation board, Tripath has used an analog ground plane to minimize
the impedances between pin 15 and pin 20 as well as the other analog ground connections, such as
V5 supply bypassing, and feedback divider networks. The ground for the V5 power supply should
connect directly to pin 20. Additionally, any external input circuitry such as preamps, or active filters,
should be referenced to pin 20.
Tripath Technology, Inc. - Technical Information
15 TA2020 – KLI/1.0/11-01
For the power section, Tripath has traditionally used a “star” grounding scheme. Thus, the load
ground returns and the power supply decoupling traces are routed separately back to the power
supply. In addition, any type of shield or chassis connection would be connected directly to the
ground star located at the power supply. These precautions will both minimize audible noise and
enhance the crosstalk performance of the TA2022.
The TA2022 incorporates a differential feedback system to minimize the effects of ground bounce
and cancel out common mode ground noise. As such, the feedback from the output ground for each
channel needs to be properly sensed. This can be accomplished by connecting the output ground
“sensing” trace directly to the star formed by the output ground return, output capacitor, CO, and the
zobel capacitor, CZ. Refer to the Application / Test Circuit for a schematic description.
Pin 3, VN10GND, is used for the VN10 buck converter. Pin 3 can be connected to the main power
supply decoupling ground trace (or plane) without any loss in functionality or reduction of
performance. This pin is electrically shorted to the copper heat sink (case) of the TA2022. Even if
the internal VN10 regulator is not being used, VN10GND should still be connected to PGND.
TA2022 Amplifier Gain
The gain of the TA2022 is the product of the input stage gain and the modulator gain. Please refer to
the sections, Input Stage Design, and Modulator Feedback Design, for a complete explanation of how
to determine the external component values.
MODULATORV EVINPUTSTAG VTA2022 A* AA =
+
+
−≈ 1
R*R
)R(R*R
R
R
A
FBBFBA
FBBFBAFBC
I
F
VTA2022
For example, using a TA2022 with the following external components,
R
I = 20kΩ
RF = 20kΩ
RFBA = 1kΩ
RFBB = 1.13kΩ
R
FBC = 9.09kΩ
V
V
18.13 1
1.13k Ω*1.0k Ω
)1.13k(1.0k Ω*9.09k Ω
20k Ω
20k Ω
AVTA2022 =
+
Ω+
−≈
Input Stage Design
The TA2022 input stage is configured as an inverting amplifier, allowing the system designer flexibility
in setting the input stage gain and frequency response. Figure 1 shows a typical application where
the input stage is a constant gain inverting amplifier. The input stage gain should be set so that the
maximum input signal level will drive the input stage output to 4Vpp.
Tripath Technology, Inc. - Technical Information
16 TA2020 – KLI/1.0/11-01
TA2022
2
INPUT2 OAOUT2
V5
OAOUT1
+
-
CI
+
-
INV1
INPUT1
BIASCAP
AGND
RF
RICI
RF
A
GND
INV2
V5
RI
Figure 1: Input Stage
The gain of the input stage, above the low frequency high pass filter point, is that of a simple inverting
amplifier: It should be noted that the input opamps are biased at approximately 2.5VDC. Thus, the
polarity of CI must be followed as shown in Figure 1 for a standard ground referenced input signal
I
F
EVINPUTSTAG R
R
A−=
Input Capacitor Selection
CI can be calculated once a value for RI has been determined. CI and RI determine the input low
frequency pole. Typically this pole is set below 10Hz. CI is calculated according to:
IP
I Rf2
1
C
π
=
where: IR= Input resistor value in ohms.
Pf = Input low frequency pole (typically 10Hz or below).
Modulator Feedback Design
The modulator converts the signal from the input stage to the high-voltage output signal. The
optimum gain of the modulator is determined from the maximum allowable feedback level for the
modulator and maximum supply voltages for the power stage. Depending on the maximum supply
voltage, the feedback ratio will need to be adjusted to maximize performance. The values of RFBA,
RFBB and RFBC (see explanation below) define the gain of the modulator. Once these values are
chosen, based on the maximum supply voltage, the gain of the modulator will be fixed even with as
the supply voltage fluctuates due to current draw.
For the best signal-to-noise ratio and lowest distortion, the maximum modulator feedback voltage
should be approximately 4Vpp. This will keep the gain of the modulator as low as possible and still
allow headroom so that the feedback signal does not clip the modulator feedback stage.
Figure 2 shows how the feedback from the output of the amplifier is returned to the input of the
modulator. The input to the modulator (FBKOUT1/FBKGND1 for channel 1) can be viewed as inputs
to an inverting differential amplifier. RFBA and RFBB bias the feedback signal to approximately 2.5V and
RFBC scales the large OUT1/OUT2 signal to down to 4Vpp.
Tripath Technology, Inc. - Technical Information
17 TA2020 – KLI/1.0/11-01
OUT 1 GROUND
RFBB
FBKGND1
RFBA
OUT1
RFBC
V5
RFBC
FBKOUT1
RFBB
RFBA
AGND
1/2 TA2022
Processing
Modulation
&
Figure 2: Modulator Feedback
The modulator feedback resistors are:
Ω
=1Ktypically specified, UserRFBA
4)-(VPP
VPP*R
RFBA
FBB =
4
VPP*R
RFBA
FBC =
1
R*R
)R(R*R
A
FBBFBA
FBBFBAFBC
MODULATOR-V +
+
≈
The above equations assume that VPP=|VNN|.
For example, in a system with VPPMAX=36V and VNNMAX=-36V,
R
FBA = 1kΩ, 1%
R
FBB = 1.125kΩ, use 1.13kΩ, 1%
R
FBC = 9.0kΩ, use 9.09kΩ, 1%
The resultant modulator gain is:
18.13V/V 1
1.13k Ω*1.0k Ω
)1.13k(1.0k Ω*9.09k Ω
A MODULATOR-V =+
Ω
+
≈
Tripath Technology, Inc. - Technical Information
18 TA2020 – KLI/1.0/11-01
Mute
The mute pin must be driven to a logic low or logic high state for proper operation. The state of the
mute pin is “latched in” to minimize the effects of noise on this pin, which could cause the TA2022 to
switch state unintentionally. Controlling the mute pin with a push-pull output from a microcontroller, or
a physical switch between V5 and AGND, works well as both solutions have low impedance drive
capability. In some cases, it may be desirable to drive the mute pin with an alternative approach.
When the device is in mute, the pin must be “pulled low” via approximately 1kohm to overcome the
internal latch and change the TA2022 state (i.e. out of mute). When the device is not in mute, the
mute pin must be “pulled high” via approximately 2kohm to overcome the internal latch and change
the TA2022 state (i.e. into mute). Figure 3 shows a simple control circuit that buffers a Mute Control
signal that is not capable of driving the Mute pin of the TA2022 directly. When the Mute Control signal
is high, the Mute pin will be driven low and the TA2022 will be on. If the Mute Control signal is low,
the 2k resistor will pull the Mute pin high and the TA2022 will be muted.
Figure 3: Low impedance drive for Mute Pin
To ensure proper device operation, including minimization of turn on/off transients that can result in
undesirable audio artifacts, Tripath recommends that the TA2022 device be muted prior to power up
or power down of the 5V supply. The “sensing” of the V5 supply can be easily accomplished by using
a “microcontroller supervisor” or equivalent to drive the TA2022 mute pin high when the V5 voltage is
below 4.5V. This will ensure proper operation of the TA2022 input circuitry. A micro-controller
supervisor such as the MCP101-450 from Microchip Corporation has been used by Tripath to
implement clean power up/down operation.
If turn-on and/or turn-off noise is still present with a TA2022 amplifier, the cause may be other circuitry
external to the TA2022. While the TA2022 has circuitry to suppress turn-on and turn-off transients,
the combination of power supply and other audio circuitry with the TA2022 in a particular application
may exhibit audible transients. One solution that will completely eliminate turn-on and turn-off pops
and clicks is to use a relay to connect/disconnect that amplifier from the speakers with the appropriate
timing during power on/off.
TA2022 Output Capability
The TA2022 can output two channels at 100 watts each into a 4ohm load at 1% THD+N. The
maximum amplifier output power is determined by a number of factors including the TA2022 junction
temperature, the load impedance and the power supply voltage.
Tripath does not recommend driving loads below 4 ohm single ended as the amplifier efficiency will
be seriously reduced and the amplifier may prematurely current limit.
MUTE
AGND
TO MUTE
(Pin 24)
2k
CONTROL
10k
V5
Tripath Technology, Inc. - Technical Information
19 TA2020 – KLI/1.0/11-01
Bridging the TA2022
The TA2022 can be bridged by returning the signal from OAOUT1 to the input resistor at INV2.
OUT1 will then be a gained version of OAOUT1, and OUT2 will be a gained and inverted version of
OAOUT1 (see Figure 3). When the two amplifier outputs are bridged, the apparent load impedance
seen by each output is halved, so the minimum recommended impedance for bridged operation is 8
ohms. Due to the internal current limit setting, the maximum supply voltage recommended for
bridged operation is +/-30V. Bridged operation into loads below 8ohms is possible, but, as mentioned
above, the amplifier efficiency will be reduced and the amplifier may prematurely current limit. The
TA2022 is capable of 150W into 8 ohms bridged at 0.1% THD+N.
AGND
OAOUT2
V5
OAOUT1
AGND
BIASCAP
V5
RI
20k
CI
INV1
RF
TA2022
INPUT
INV2
+
-
+
-
20k
Figure 4: Input Stage Setup for Bridging
The switching outputs, OUT1 and OUT2, are not synchronized, so a common inductor may not be
used with a bridged TA2022. For this same reason, individual zobel networks must be applied to
each output to load each output and lower the Q of each common mode differential LC filter.
Output Voltage Offset
The output offset voltage of the TA2022 is largely determined by the matching of the respective RFBA,
RFBB, and RFBC networks for FBKOUT1(FBKOUT2) and FBKGND1 (FBKOUT2). Thus, the intrinsic
offset of the TA2022 can be altered by the external feedback network resistor matching. To minimize
the nominal untrimmed offset voltage, 1% tolerance resistors are recommended.
In most applications, the output offset voltage will need to be trimmed via an external circuit (either
passive or active). The output offset voltage of the TA2022 can be nulled by modifying the modulator
feedback as shown in Figure 4. Potentiometer ROFA is used to trim the effective resistance seen by
the output ground, and therefore the output offset. ROFB limits the trim range.
Tripath Technology, Inc. - Technical Information
20 TA2020 – KLI/1.0/11-01
Figure 5: Manual Output Offset Trim Circuit
A DC servo can also be used to automatically null any offset voltage. The TA2022 evaluation board
incorporates a DC servo. Please refer to the TA2022 evaluation board document, EB-TA2022,
available on the Tripath website, at www.tripath.com.
Current Protection Design
Although the over-current (Ioc) trip point is internally fixed, there are external components that can
affect output current levels during a short circuit event. Referring to the Application/Test diagram
these include the output inductor (Lo), output diodes (Do) and supply bypassing (Cs).
The two output inductors, Lo, directly impact the peak output current levels reached during short
circuit events. For this reason they must be rated at least 10A regardless of the systems maximum
operating current, ensuring the inductor does not saturate which could lead to switching currents
passing unimpeded to the load. When this occurs, the Ioc may be forced to trip on average current
levels instead of peak current levels, directly impacting the current levels seen by the load and
potentially causing damage to the TA2022. Please refer to the Output Filter Design section for more
details on the inductor requirements and figure 6 for comparison of load currents with an unsaturated
and saturated inductor.
The four output diodes, Do, minimize overshoots and undershoots with respect to the supply rails
VPP and VNN. In order for these diodes to work properly they must have a low Forward Voltage
rating at 10A. We recommend a Fast Recovery diode or Ultra-Fast PN Rectifier diode with a Vf rating
of 1V at 10A, or better. Also, These should be placed close to their respective output pins to
maximum effectiveness.
The two bulk supply voltage capacitors, Cs, will absorb the current generated when the diodes (Do)
conduct. We recommend that a high frequency capacitor designed for low impedance and high ripple
currents be used. Tripath recommends an impedance of .1Ω or better at 100kHz and a ripple current
rating of 1Arms at 100kHz. For maximum effectiveness, Tripath recommends that these capacitors be
placed close to their respective supply pins.
RFBC
10K
Processing
RFBB
&
OUT1
OUT 1 GROUND
RFBB
RFBC
V5
FBKOUT1
AGND
RFBA
ROFB
ROFA
50K
1/2 TA2022
RFBA
FBKGND1
Modulation
Tripath Technology, Inc. - Technical Information
21 TA2020 – KLI/1.0/11-01
Figure 6: Short circuit load current with unsaturated toroidal inductor and
saturated bobbin Inductor (shielded)
Output Filter Design
Tripath amplifiers generally have a higher switching frequency than PWM implementations allowing
the use of higher cutoff frequency filters, reducing the load dependent peaking/drooping in the 20kHz
audio band. This is especially important for applications where the end customer may attach any
speaker to the amplifier (as opposed to a system where speakers are shipped with the amplifier),
since speakers are not purely resistive loads and the impedance they present changes over
frequency and from speaker model to speaker model. An RC network, or “zobel” (RZ, CZ) must be
placed at the filter output to control the impedance “seen” by the TA2022. The TA2022 works well
with a 2nd order, 107kHz LC filter with LO = 10uH and CO = 0.22uF and RZ = 6.2ohm/2W and CZ =
0.22uF. Some applications may require a more aggressive filter to reduce out of band noise. Below
are some proven filter combinations:
- 49.5kHz 2nd order filter - 33.6kHz 2nd order filter
LO = 22uH LO = 33uH
CO = .47uF CO = .68uF
RZ = 8Ω RZ = 6.2Ω
CZ = .47uF CZ = .68uF
- 65kHz 4th order filter
LO1 = 15uH
CO1 = 1uF
LO2 = 10uH
CO2 = .22uF
RZ = 10Ω
CZ = .47uF
Output inductor selection is a critical design step. The core material and geometry of the output filter
inductor affects the TA2022 distortion levels, efficiency, over-current protection, power dissipation and
EMI output. The inductor should have low loss at 700kHz with 80Vpp. It should be reiterated that
regardless of the systems maximum operating current, a 10A rating is required to ensure that peak
current conditions will not cause the inductor to saturate. During a short circuit event the inductor
current increases very quickly in a saturated core (see figure 6), compromising the current protection
scheme. A 10A rating is sufficient to ensure that current increases through the inductor are linear, and
provides a safety margin for the TA2022. There are two types of inductors available in the 10A range
that offers some EMI containment: they are the toroidal type and the bobbin (shielded) type inductor.
In bobbin construction, a ferrite shield is placed around the core of a bobbin inductor to help contain
radiated emissions. This shield can reduce the amount of energy the inductor can store in the core by
reducing the air gap, which can lower the peak current capability of the inductor. Typically, a 7-10A
shielded bobbin inductor will not have the peak current capability necessary to ensure that the core
Tripath Technology, Inc. - Technical Information
22 TA2020 – KLI/1.0/11-01
will not saturate during short circuit events; this is why they are not recommended for use with the
TA2022. Also it should be noted that shielded bobbin construction is not as effective as toroidal
construction for EMI containment.
Tripath recommends that the customer use a toroidal inductor with a Carbonyl-E core for all
applications of the TA2022. This core has a high peak current capability due to its low-µ Carbonyl-E
metal powder. A distributed air gap increases its’ energy storage capability, which allows for a small
footprint and high current capability. Carbonyl-E toroidal iron powder cores have low loss and good
linearity. The toroidal shape is ideal for EMI containment. Also, EMI can be further contained by sizing
the toroid to accept a full layer of windings. This aids in shielding the electric field. Tripath
recommends:
- Micrometals (www.micrometals.com) Type-2 (Carbonyl-E) toroidal iron powder cores. The
specific core Tripath initially verified and used on the EB-TA2022 was a T94-2 (23.9mm
outer diameter) wound to 11uH with 19AWG wire. Since then Tripath has determined that
much smaller Carbonyl-E toroids will not saturate during high current events. Tripath has
also used T68-2 (17.5mm outer diameter) and the T60-2B/60(15.2mm outer diameter)
cores wound to 11uH with 22AWG with good success. If a smaller core is required, core
outer diameters as small as 15.2mm (T60-2) work well, but core temperature effects should
be tested. The T60-2 core did not saturate during short circuit testing, but maximum core
temperatures must be considered and multiple layer winding must be used to achieve
11uH. Multiple winding can increase winding capacitance, which may cause ringing and
increased radiated emissions. Bank winding techniques can minimize this effect. It should
be noted that at core temperatures above 130C the single build wire used by most inductor
manufacturers should be replaced with a heavy build wire. Micrometals does not provide
winding services, but many companies purchase directly from them and provide completely
finished inductors. Pulse Engineering has assigned a part number for the T68-2 wound with
44 turns of 22 AWG single build wire. The part number is PA0291.
- Amidon Inc./American Cores type-06 (Carbonyl-E) toroidal iron powder cores. Tripath has
used T690-06 (17.5mm outer diameter) cores wound to 11uH with good success. Amidon
carries type-06 cores in the 23.9mm to 15.2mm outer diameter range. They have assigned
a part number for the T690-06 wound with 44 turns of 22 AWG single build wire. This part
is approved by Tripath and is 690064422.
Power Supplies
The TA2022 requires the split supply rails VPP1(VPP2) and VNN1(VNN2), and V5. It also uses
some additional voltages, VN10, VBOOT1 and VBOOT2 that are generated internally. The selection
of components for the switching regulator is shown in the Application / Test Diagram.
Minimum and Maximum Supply Voltage Operating Range
The TA2022 can operate over a wide range of power supply voltages from +/-12V to +/-36V. In order
to optimize operation for either the low or high range, the user must select the proper values for
RVNNSENSE, RVPPSENSE, RFBA, RFBB, and RFBC. Please refer to the Modulator Feedback Design and
Over/Under-voltage Protection sections for more additional information.
VN10 Supply
The TA2022 has an internal hysteretic buck converter, which, in conjunction with a few passive
components, generates the necessary floating power supply for the MOSFET driver stage (nominally
11V with the external components shown in Application / Test Circuit). The performance curves
shown in the data sheet as well as efficiency measurements were done using the internal VN10
generator. Tripath recommends that the internal VN10 generator be used.
In some cases, though, a designer may wish to use an external VN10 generator. The specification
for VN10 quiescent current (65mA typical, 80mA maximum) in the Electrical Characteristics section
states the amount of current needed when an external floating supply is used. If the internal VN10
Tripath Technology, Inc. - Technical Information
23 TA2020 – KLI/1.0/11-01
generator is not used, Tripath recommends shorting VN10SW(pin 5) to VN10GND(pin 3) and
VN10FDBK(pin 14) to VN10GND(pin 3). VN10GND should still be connected to the system power
(high current) ground star for noise reasons.
The external VN10 supply must be able to source a maximum of 80mA into the VN10 pin. Thus, a
positive supply must be used. In addition, this supply must be referenced to the VNN rail. If the
external VN10 supply does not track fluctuations in the VNN supply or is not able to source current
into the VN10 pin, the TA2022 will, at the very least, not work, but more likely, be permanently
damaged.
Figure 7 shows a simple circuit for an external VN10 supply. Though simple, there is one problem
with this circuit; the maximum input voltage of the 7810. If the maximum input voltage of the 7810 is
exceeded (typically this voltage is 35V), then the 7810 will be damaged which will likely
cause damage to the TA2022. Thus, this circuit should only be used where the VNN power supply is
well regulated even under heavy load conditions (including the effects of power supply pumping).
Figure 7: Simple External VN10 Supply
Figure 8 shows a much more robust VN10 supply. In this case, the maximum supply differential the
LM317 experiences is the input voltage minus the output voltage. The maximum differential
specification is 40V for the LM317. When used as the VN10 supply for the TA2022, the maximum
differential the LM317 will experience is 25V, even at maximum operating voltage of 36V for the
TA2022. As configured, VOUT will be about 10.63V above VNN.
Figure 8: Robust External VN10 Supply
It should be noted that the maximum power dissipation for either Figure 6 or Figure 7 is:
1.6W80mA(max.)11V)(31VIOUTVOUT)(VINP DMAX =
×
−
≈
×−=
Thus, the LM7810 or LM317 must be sufficiently heat sinked to sustain 80mA in the system ambient
temperature. In the case where multiple TA2022’s are run off the same VN10 generator, the power
dissipation may be prohibitively large for the linear regulator in conjunction with allowable heat sink.
In these cases, a more sophisticated scheme using an additional transformer secondary winding
referenced to VNN may be necessary to minimize the linear regulator power dissipation.
VIN TO VN10 (PIN 2)
VOUT
0.1uF 0.1uF10uF
7810
"GND"
TO POWER SUPPLY
"STAR" GND 10uF
TO VNN (PIN 8,9)
ADJ
0.1uF
VIN
240
VOUT
10uF
1.8k
10uF
TO POWER SUPPLY
"STAR" GND
TO VNN (PIN 8,9)
0.1uF
TO VN10 (PIN 2)
10uF
LM317
Tripath Technology, Inc. - Technical Information
24 TA2020 – KLI/1.0/11-01
Protection Circuits
The TA2022 is guarded against over-current, over / under-voltage and over-temperature conditions.
If the device goes into an over-current or over / under-voltage condition, the HMUTE goes to a logic
HIGH indicating a fault condition. When this occurs, the amplifier is muted, all outputs are TRI-
STATED, and will float to approximately 2.5VDC.
Over-Current Protection
An over-current fault occurs if more than approximately 8 amps of current flows from any of the
amplifier output pins. This can occur if the speaker wires are shorted together or if one side of the
speaker is shorted to ground. An over-current fault sets an internal latch that can only be cleared if
the MUTE pin is toggled or if the part is powered down. See the over-current curves in the Typical
Characteristics section for more information.
Over/Under Voltage Protection
The TA2022 has built-in over and under voltage protection for both the VPP and VNN supply rails.
The nominal operating voltage will typically be chosen as the supply “center point.” This allows the
supply voltage to fluctuate, both above and below, the nominal supply voltage.
VPPSENSE (pin 19) performs the over and undervoltage sensing for the positive supply, VPP.
VNNSENSE (pin 18) performs the same function for the negative rail, VNN. In the simplest
implementation, the supply is done via a single, external resistor per sense pin. This scheme is
referred to as the “single resistor” sense circuit. Figure 9 shows the single resistor sense circuit.
Figure 9: Single Resistor Sense Circuit
When the current through RVPPSENSE (or RVNNSENSE) goes below or above the values shown in the
Electrical Characteristics section (caused by changing the power supply voltage), the TA2022 will be
muted. VPPSENSE is internally biased at 2.5V and VNNSENSE is biased at 1.25V. For the “single
resistor” sense case (as shown in the Application / Test Diagram), these bias points must be taken
into consideration when calculating the RVPPSENSE or RVNNSENSE resistor.
Once the supply comes back into the supply voltage operating range (as defined by the supply sense
resistors), the TA2022 will automatically be unmuted and will begin to amplify. There is a hysteresis
range on both the VPPSENSE and VNNSENSE pins. If the amplifier is powered up in the hysteresis
band the TA2022 will be muted. Thus, the usable supply range is the difference between the over-
voltage turn-off and under-voltage turn-off for both the VPP and VNN supplies. It should be noted that
there is a timer of approximately 200mS with respect to the over and under voltage sensing circuit.
VPP
19
TA2022
18
VNN
RVPPSENSE
VNNSENSE
VPPSENSE
RVNNSENSE
Tripath Technology, Inc. - Technical Information
25 TA2020 – KLI/1.0/11-01
Thus, the supply voltage must be outside of the user defined supply range for greater than 200mS for
the TA2022 to be muted.
The equation for calculating RVPPSENSE is as follows:
VPPSENSE
VPPSENSE I
2.5V - VPP
R=
The equation for calculating RVNNSENSE is as follows:
VNNSENSE
VNNSENSE I
VNN-1.25V
R=
where IVPPSENSE or IVNNSENSE can be any of the currents shown in the Electrical Characteristics
table for VPPSENSE and VNNSENSE, respectively.
Example: Nominal supply voltage – +/-32.5V +/-10%
From this information, a value of RVPPSENSE and RVNNSENSE can be calculated using the above
formulas.
36V use35.75V1.132.5VVPP MAX =×=
36V- use35.75V1.132.5VVNN MAX
−
=
×−=
%1,k243use242.75
A138
2.5V -36V
R VPPSENSE Ω== kΩ
µ
where IVPPSENSE is the minimum over-voltage turn off current for VPPSENSE.
%1,k249use245.1
A152
36V- -1.25V
R VNNSENSE Ω== kΩ
µ
where IVNNSENSE is the minimum over-voltage turn off current for VNNSENSE.
Using the resistor values from above, the actual minimum over voltage turn off points will be:
36.03V2.5V138kΩ243VPP N_OFFMIN_OV_TUR
=
+
×
=µA
36.60V-A152kΩ4921.25VVNN N_OFFMIN_OV_TUR
=
×
−
=
The other three trip points can be calculated using the same formula but inserting the appropriate
IVPPSENSE (or IVNNSENSE) current value. As stated earlier, the usable supply range is the difference
between the minimum overvoltage turn off and maximum under voltage turn-off for both the VPP and
VNN supplies.
N_OFFMAX_UV_TURN_OFFMIN_OV_TUR RANGE VPP-VPPVPP =
N_OFFMAX_UV_TURN_OFFMIN_OV_TUR RANGE VNN-VNNVNN =
Using the resistor values from above, and the maximum under voltage trip currents shown in the
Electrical Characteristics table, the maximum under voltage turn off points will be:
23.64V2.5V87kΩ243VPP N_OFFMAX_UV_TUR
=
+
×
=A
22.41V-A95kΩ4921.25VVNN N_OFFMAX_UV_TUR
=
×
−
=
Tripath Technology, Inc. - Technical Information
26 TA2020 – KLI/1.0/11-01
and the resultant supply ranges will be:
12.39V23.64V03.36VPP RANGE
=
−=
14.19V-22.41V60.36VNN RANGE
=
−−−=
It should also be noted that the tolerance of the RVPPSENSE (or RVNNSENSE) resistors will effect the trip
voltages and thus, the usable supply range. To minimize the additional variance Tripath recommends
1% tolerance resistors.
As a matter of completeness, the formulas below include the effect of resistor tolerance assuming a
known value of RVPPSENSE or RVNNSENSE.
2.5V)100/TOL1()IR(VPP TRIPVPPSENSE N_OFFMIN_OV_TUR
+
+
÷
×
=
2.5V)100/TOL1()IR(VPP TRIPVPPSENSE N_OFFMAX_UV_TUR
+
+
×
×
=
)100/TOL1()IR(25.1VNN TRIPVNNSENSE N_OFFMIN_OV_TUR
+
÷
×
−
=
)100/TOL1()IR(25.1VNN TRIPVNNSENSE N_OFFMAX_UV_TUR
+
×
×
−
=
Using a value of 243kΩ for RVPPSENSE and a value of 249kΩ for RVNNSENSE, assuming 5% tolerance,
along with the appropriate value of ITRIP, the trip voltages and supply ranges can be calculated.
34.44V 2.5V)100/51()138243k Ω(VPP N_OFFMIN_OV_TUR =
+
+
÷
×
=A
24.70V 2.5V)100/51()µA87243k Ω(VPP N_OFFMAX_UV_TUR =
+
+
×
×
=
9.74V24.70V44.34VPP RANGE
=
−=
34.80V)100/51()µA152kΩ492(25.1VNN N_OFFMIN_OV_TUR −=
+
÷
×
−
=
23.59V)100/51()µA95kΩ492(25.1VNN N_OFFMAX_UV_TUR −=
+
×
×
−
=
11.21V-23.59V80.34VNN RANGE
=
−−−=
Thus, by using 5% resistors, the supply range for the VPP has been reduced by 2.65V while the VNN
range has been reduced by approximately 3.0V (as compared to resistors with no tolerance
variation). In actuality, if a 5% resistor was to be used, then the initial value of RVPPSENSE and
RVNNSENSE would have had to be adjusted such that the minimum over voltage turn off points would
have never been less than +/-36V as defined by the supply voltage and tolerance specification.
It should be noted that the values for VVPPSENSE and VVNNSENSE shown in the Electrical Characteristics
table were calculated using a value of 249kΩ for both RVPPSENSE and RVNNSENSE. In addition, for the
maximum and minimum values, as opposed to the typical ones, a 1% tolerance resistor value around
249kΩ was chosen to show the effect on supply range. Thus, the minimum and maximum values
would be “worst case” assuming a supply voltage of 5V for the input section of the TA2022.
The entire discussion thus far has been for the “one resistor” sense circuit. This configuration
requires a single resistor from either VPPSENSE or VNNSENSE to the respective power supply.
While the simplest configuration, in terms of external components, there are some drawbacks to this
configuration. The first drawback is that the range for VPPRANGE and VNNRANGE are asymmetric due
to the different internal bias voltages of VPPSENSE and VNNSENSE. A second issue is that current
through RVPPSENSE or RVNNSENSE will change if the V5 voltage is not exactly 5V, since the bias voltages
of pin 18 and pin 19 are set by resistor dividers between V5 and AGND.
With an additional resistor per supply sense pin (2 resistors per VPPSENSE or VNNSENSE), the
drawbacks of the “one resistor” sense circuit can be eliminated. In addition, the calculations of the
sense resistors are actually more straightforward for the “two resistor” sense circuit as opposed to the
“one resistor” scheme. Figure 10 shows the proper connection for the “two resistor” sense circuit for
both the VPPSENSE and VNNSENSE pins.
Tripath Technology, Inc. - Technical Information
27 TA2020 – KLI/1.0/11-01
Figure 10: Two Resistor Sense Circuit
The equation for calculating RVPP1 is as follows:
VPPSENSE
VPP1 I
VPP
R=
Set VPP1 VPP2 RR =.
The equation for calculating RVNNSENSE is as follows:
VNNSENSE
VNN1 I
VNN
R=
Set VNN1 VNN2 R3R ×= .
IVPPSENSE or IVNNSENSE can be any of the currents shown in the Electrical Characteristics table
for VPPSENSE and VNNSENSE, respectively.
Example: Nominal supply voltage – +/-32.5V +/-10%
From this information, a value of RVPP1, RVPP2, RVNN1, and RVNN2 can be calculated using the above
formulas.
36V use35.75V1.132.5VVPP MAX =×=
36V- use35.75V1.132.5VVNN MAX
−
=
×−=
%1,k261use260.87
A138
36V
R VPP1 Ω== kΩ
µ
Set %1,261 RVPP2 Ω= k.
where IVPPSENSE is the minimum over-voltage turn off current for VPPSENSE.
%1,k237use236.84
A152
36V
R VNN2 Ω== kΩ
µ
Set %1,kΩ715 RVNN2 =.
where IVNNSENSE is the minimum over-voltage turn off current for VNNSENSE.
RVNN2
TA2022
RVNN1
RVPP1
VPP
18 VNNSENSE
VPPSENSE
RVNN2
V5 VNN
V5
19
Tripath Technology, Inc. - Technical Information
28 TA2020 – KLI/1.0/11-01
The two additional resistors, RVPP2 and RVNN2 compensate for the internal bias points. Thus, RVPP1
and RVNN1 can be used for the direct calculation of the actual VPP and VNN trip voltages without
considering the effect of RVPP2 and RVNN2.
Using the resistor values from above, the actual minimum over voltage turn off points will be:
36.02V138kΩ261VPP N_OFFMIN_OV_TUR
=
×
=A
36.24V-A152kΩ372VNN N_OFFMIN_OV_TUR
=
×
−=
The other three trip points can be calculated using the same formula but inserting the appropriate
IVPPSENSE (or IVNNSENSE) current value. As stated earlier, the usable supply range is the difference
between the minimum overvoltage turn off and maximum under voltage turn-off for both the VPP and
VNN supplies.
N_OFFMAX_UV_TURN_OFFMIN_OV_TUR RANGE VPP-VPPVPP =
N_OFFMAX_UV_TURN_OFFMIN_OV_TUR RANGE VNN-VNNVNN =
Using the resistor values from above, and the maximum under voltage trip currents shown in the
Electrical Characteristics table, the maximum under voltage turn off points will be:
22.71V87kΩ261VPP N_OFFMAX_UV_TUR
=
×
=A
22..51V-A95kΩ372 VNN N_OFFMAX_UV_TUR
=
×
−=
and the resultant minimum supply ranges will be:
13.31V22.71V02.36VPP RANGE
=
−=
13.73V-22.51V24.36VNN RANGE
=
−−−=
By adding a total of 2 additional resistors (1 for VPPSENSE and 1 for VNNSENSE), the minimum
supply range is now about 3% different as opposed to 13% for the “single resistor” sense case. In
addition, the VPP range has been increased by nearly one volt. This represents a 7% improvement
in supply range for VPP. As in the single resistor case, the tolerance of the RVPP1 and RVPP2 (or RVNN1
and RVNN2) resistors will affect the trip voltages and thus, the usable supply range. As the nominal
supply voltage is decreased, the effect of RVPP2 and RVNN2 becomes more pronounced. To minimize
the additional variance Tripath recommends 1% tolerance resistors. It is possible to calculate the
effect of resistor tolerances for the “two resistor” sense circuit, but ultimately, 1% resistors should be
used for the sense circuit in all, but the tightest regulated supply schemes.
Over Temperature Protection
An over-temperature fault occurs if the junction temperature of the part exceeds approximately
165°C. The thermal hysteresis of the part is approximately 30°C, therefore the fault will automatically
clear when the junction temperature drops below 135°C.
HMUTE (pin 32)
The HMUTE pin is a 5V logic output that indicates various fault conditions within the device. These
conditions include: over-current, overvoltage and undervoltage. The HMUTE output is capable of
directly driving an LED through a series 2kΩ resistor.
Heat Sink Requirements
most applications it will be necessary to fasten the TA2022 to a heat sink. The determining factor is
that the 150°C maximum junction temperature, TJ(max) cannot be exceeded, as specified by the
following equation:
Tripath Technology, Inc. - Technical Information
29 TA2020 – KLI/1.0/11-01
PDISS =
(
)
JA
A)MAX(J TT
θ
−
where:
PDISS = maximum power dissipation
TJMAX = maximum junction temperature of TA2022
TA = operating ambient temperature
θJA = junction-to-ambient thermal resistance
θJA = θJC + θCS + θSA
Example:
What size heat sink is required to operate the TA2022 at 80W per channel continuously in a 70ºC
ambient temperature?
P
DISS is determined by:
Efficiency =
η =
IN
OUT
P
P=
DISSOUT
OUT
PP
P
−
PDISS (per channel) = W88.5190
85.0
90 =−=− OUT
OUT P
P
η
Thus, PDISS for two channels = 31.76W
θJA =
(
)
DISS
A)MAX(J
P
TT − = 76.31
70150
−
= 2.52°C/W
The θJC of the TA2022 is 1.0°C/W, so a heat sink of 1.32°C/W is required for this example (assuming
a θCS = 0.2°C/W). In actual applications, other factors such as the average PDISS with a music source
(as opposed to a continuous sine wave) and regulatory agency testing requirements will help
determine the size of the heat sink required.
Performance Measurements of the TA2022
The TA2022 operates by generating a high frequency switching signal based on the audio input. This
signal is sent through a low-pass filter (external to the Tripath amplifier) that recovers an amplified
version of the audio input. The frequency of the switching pattern is spread spectrum in nature and
typically varies between 100kHz and 1MHz, which is well above the 20Hz – 20kHz audio band. The
pattern itself does not alter or distort the audio input signal, but it does introduce some inaudible
components.
The measurements of certain performance parameters, particularly noise related specifications such
as THD+N, are significantly affected by the design of the low-pass filter used on the output as well as
the bandwidth setting of the measurement instrument used. Unless the filter has a very sharp roll-off
just beyond the audio band or the bandwidth of the measurement instrument is limited, some of the
inaudible noise components introduced by the TA2022 amplifier switching pattern will degrade the
measurement.
One feature of the TA2022 is that it does not require large multi-pole filters to achieve excellent
performance in listening tests, usually a more critical factor than performance measurements.
Though using a multi-pole filter may remove high-frequency noise and improve THD+N type
measurements (when they are made with wide-bandwidth measuring equipment), these same filters
degrade frequency response. The TA2022 Evaluation Board uses the Application/Test Circuit of this
data sheet, which has a simple two-pole output filter and excellent performance in listening tests.
Measurements in this data sheet were taken using this same circuit with a limited bandwidth setting in
the measurement instrument.
Tripath Technology, Inc. - Technical Information
30 TA2020 – KLI/1.0/11-01
PACKAGE INFORMATION
48-pin DIP
Tripath Technology, Inc. - Technical Information
31 TA2020 – KLI/1.0/11-01
ADVANCED INFORMATION
This is a product in development. Tripath Technology, Inc. reserves the right to make any changes without
further notice to improve reliability, function and design.
Tripath and Digital Power Processing are trademarks of Tripath Technology, Inc. Other trademarks
referenced in this document are owned by their respective companies.
Tripath Technology, Inc. reserves the right to make changes without further notice to any products herein to
improve reliability, function or design. Tripath does not assume any liability arising out of the application of
use of any product or circuit described herein; neither does it convey any license under its patent rights nor
the rights of others.
TRIPATH’S PRODUCT ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE
SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN CONSENT OF THE
PRESIDENT OF TRIPATH TECHONOLOGY, INC. As used herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and whose failure to perform, when properly used in
accordance with instructions for use provided in this labeling, can be reasonably expected to result
in significant injury of the user.
2. A critical component is any component of a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system, or to affect its
safety or effectiveness.
Other useful documents concerning the TA2022 available on the Tripath website.
• EB-TA2022 Evaluation Board – TA2022 Evaluation Board Document
• RB-TA2022 Six Channel Board – Six channel reference design using the TA2022.
Contact Information
TRIPATH TECHNOLOGY, INC
2560 Orchard Parkway, San Jose, CA 95131
408.750.3000 - P
408.750.3001 - F
For more Sales Information, please visit us @ www.tripath.com/cont_s.htm
For more Technical Information, please visit us @ www.tripath.com/data.htm