T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

TC2000

STEREO CLASS-TTM AUDIO CONTROLLER USING DIGITAL
POWER PROCESSING (DPPTM) TECHNOLOGY

T e c h n i c a l I n f o r m a t i o n R e v i s i o n 1 . 1 D e c e m b e r 2 0 0 3

G E N E R A L D E S C R I P T I O N

The TC2000 is a two channel audio controller that uses Tripath's proprietary Digital Power
Processing (DPP

) technology. When combined with switching power output stages, the

TC2000 allows the implementation of a complete Class-T audio amplifier. Class-T amplifiers offer
both the audio fidelity of Class-AB and the power efficiency of Class-D amplifiers.

A P P L I C A T I O N S

5.1-Channel DVD

Mini/Micro Component Systems

Home Theater

Stereo applications

B E N E F I T S

High fidelity, high efficiency Class-T

Analog inputs

F E A T U R E S

Class-T Architecture

Audiophile Quality Sound

0.007% THD+N @ 30W 8

(with TP2050)

High Efficiency

92% @ 60W 8 (with TP2050)

Dynamic Range >100 dB

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

A B S O L U T E M A X I M U M R A T I N G S

(Note 1)

SYMBOL PARAMETER

Value

UNITS

5V Power Supply

Vlogic Input

Logic

Level

+0.3V V

Operating Free-air Temperature Range

-40 to 85

°C

STORE

Storage Temperature Range

-55 to 150

°C

JMAX

Maximum Junction Temperature

150

°C

ESD

ESD Susceptibility Human Body Model (Note 2), all pins

2000

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

See the table below for Operating Conditions.

Note 2: Human body model, 100pF discharged through a 1.5K

resistor.

O P E R A T I N G C O N D I T I O N S

SYMBOL PARAMETER MIN.

TYP.

MAX.

UNITS

Supply Voltage

4.5

5.5

Logic Input High

V5-1.0

Logic Input Low

Operating Temperature Range

-40

°C

T H E R M A L C H A R A C T E R I S T I C S

TC2000

SYMBOL PARAMETER

Value

UNITS

Junction-to-ambient Thermal Resistance (still air)

°C/W

E L E C T R I C A L C H A R A C T E R I S T I C S

SYMBOL PARAMETER MIN.

TYP.

MAX.

UNITS

Supply Current

fsw

Switching Frequency (adjustable via CFB)

600

650

kHz

Input

Sensitivity

1.5

OUTHI

High Output Voltage

V5-0.5

OUTLO

Low Output Voltage

100

Input

Impedance

Input

Bias

2.5

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

T C 2 0 0 0 A U D I O S I G N A L P R O C E S S O R P I N D E S C R I P T I O N S

Pin Function

Description

1 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.

2, 6

FDBKP2, FDBKP1

Positive switching feedback.

3 DCMP

Internal mode selection. This pin must be grounded for proper device
operation.

4, 7

FDBKN2, FDBKN1

Negative switching feedback.

VPWR

Test pin. Must be left floating.

8 HMUTE

Logic output. A logic high indicates both amplifiers are muted, due to the mute pin state, or
a "fault".

9, 12

Y1, Y2

Non-inverted switching modulator outputs.

10, 11

Y1B, Y2B

Inverted switching modulator outputs.

13 NC

connect

14,16

OCD2, OCD1

Over Current Detect. Ground if not used.

REF

Internal reference voltage; approximately 1.2 VDC.

VNNSENSE

Negative power stage over/under supply voltage sense resistor tie point.

OVRLDB

A logic low output indicates the input signal has overloaded the amplifier.

VPPSENSE

Positive power stage over/under supply voltage sense resistor tie point.

20 AGND

Ground

5 Volt power supply input.

22, 27

OAOUT1, OAOUT2

Input stage output pins.

23, 28

INV1, INV2

Single-ended inputs. Inputs are a "virtual" ground of an inverting opamp with
approximately 2.4VDC bias.

24 MUTE

When set to logic high, both amplifiers are muted and in idle mode. When low (grounded),
both amplifiers are fully operational. If left floating, the device stays in the mute mode.
Ground if not used.

25, 26

BBM1, BBM0

Break-before-make timing control.

T C 2 0 0 0 A U D I O S I G N A L P R O C E S S O R P I N O U T

BIASCAP

FDBKP2

DCMP

FDBKN2

VPW R

FDBKP1

FDBKN1

HMUTE

Y1B

Y2B

OCD2

REF

OCD1

VNNSENSE

OVRLDB

VPPSENSE

AGND

OAOUT1

INV1

MUTE

BBM1

BBM0

OAOUT2

INV2

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

A P P L I C A T I O N / T E S T D I A G R A M

Inputs and TC2000

RO FA

500K

CO F

.1u;50V

RFBC

RFBB

20K

.1u;50V

RO FA

500K

RFBB

O U T1A

CFB

IN 2

TC 2000

IN 1

RO FA

500K

RO FA

500K

CFB

RO FB

2.2u;10V

RFBC

20K

2.2u;10V

CFB

CO F

.1u;50V

20K

O U T2A

.1u;50V

RFBB

20K

RO FB

RFBC

J10

RCA

RREF

8.2K

CFB

O U T1B

JUMPER

RCA

CS
100u;16V

RFBB

O U T2B

Y1B

HMUTE

Y2B

RFBC

REF

O CD0

VNNSENSE

O VRLDB

VPPSENSE

AG ND

O AO UT1

INV1

MUTE

BBM2

BBM1

O AO UT2

INV2

BIASCAP

FDBKP2

DCMP

FDBKN2

VPW R

FDBKP1

FDBKN1

HMUTE

Y1B

Y2B

O CD1

RVNNSENSE

10k

RVPPSENSE

20k

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

E X T E R N A L C O M P O N E N T S D E S C R I P T I O N

(Refer to the Application/Test Circuit)

Component Description
RI

Inverting input resistance to provide AC gain in conjunction with R

. This input is

biased at the BIASCAP voltage (approximately 2.5VDC).

Feedback resistor to set AC gain in conjunction with R

. Please refer to the

Amplifier Gain paragraph, in the Application Information section.

AC input coupling capacitor, which, in conjunction with R

, forms a high pass filter

)

(

RFBB

Feedback divider resistor connected to AGND. The value of this resistor depends
on the supply voltage setting and helps set gain in conjunction with R

FBB,

and R

FBC

. Please see the Modulator Feedback Design paragraphs in the

Application Information Section.

RFBC

Feedback resistor connected from either the OUT1A/OUT2A to FDBKP1/FDBKP2
or OUT1B/OUT2B to FDBKN1/FDBKN2. The value of this resistor depends on
the supply voltage setting and helps set gain in conjunction with R

FBB,

and

FBC

. It should be noted that the resistor from OUT1/OUT2 to

FBKOUT1/FBKOUT2 must have a power rating of greater than

)

(2R

VPP

FBC

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 C

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.

ROFB

Potentiometer used to manually trim the DC offset on the speaker output.

ROFA

Resistor that limits the manual DC offset trim range and allows for more precise
adjustment.

RREF

Bias resistor. Locate close to pin 15 and ground at pin 20.

Supply decoupling for the power supply pins. For optimum performance, these
components should be located close to the TC2000 and returned to their
respective ground as shown in the Application/Test Circuit.

RVNNSENSE

Resistor used to terminate the VNNSENSE pin to AGND.

RVPPSENSE

Resistor used to terminate the VPPSENSE pin to 5V.

A P P L I C A T I O N I N F O R M A T I O N
T K 2 0 5 0 B a s i c A m p l i f i e r O p e r a t i o n

The TC2000 is a 5V CMOS signal processor 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 externally set by the CFB. 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 with the TP2050 are 470pF for
channel 1 and 390pF for channel 2.

Complementary copies of the switching pattern are output through the Y1 and Y1B pins and the Y2
and Y2B pins. These signals are used to drive the inputs of a MOSFET driver. In the generation of
the patterns for the MOSFET driver the TC2000 inserts a "break-before-make" dead time between the

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

turn-off of one transistor and the turn-on of the other in order to minimize shoot-through currents. For
applications using the TP2050 please tie BBM0 and BBM1 to 5V for optimal operation.

I n p u t S t a g e D e s i g n

The TC2000 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.

TC2000

INPUT2

OAOUT2

OAOUT1

INV1

INPUT1

BIASCAP

AGND

INV2

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 amplifiers are biased at approximately 2.5VDC. Thus, the
polarity of C

must be followed as shown in Figure 1 for a standard ground referenced input signal

STAGE

INPUT

I n p u t C a p a c i t o r S e l e c t i o n

can be calculated once a value for R

has been determined. C

and R

determine the input low

frequency pole. Typically this pole is set below 10Hz. C

is calculated according to:

where:

= Input resistor value in ohms.

= Input low frequency pole (typically 10Hz or below)

M o d u l a t o r F e e d b a c k D e s i g n

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 voltage for the power stage. Depending on the maximum supply
voltage, the feedback ratio will need to be adjusted to maximize performance. The values of 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 as the supply
voltage fluctuates due to current draw.

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

For the best signal-to-noise ratio and lowest distortion, the maximum differential 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.

The modulator feedback resistors are:

FBB

= User specified; typically1k

FBB

FBC

M u t e C o n t r o l

When a logic high signal is supplied to MUTE, both amplifier channels are muted (both high- and low-
side transistors are turned off). When a logic level low is supplied to MUTE, both amplifiers are fully
operational.

O u t p u t V o l t a g e O f f s e t

The TC2000 does not have internal compensation for DC offset. If offset is a consideration for the
intended application, trimming of the input offset voltage will be required. Tripath has had success
with both active and passive circuits for this purpose; please consult with the Tripath Applications
team for further information.

H M U T E

The HMUTE pin is a 5V logic output that indicates various fault conditions within the device.

O V R L D B

The OVRLDB pin is a 5V logic output that is asserted just at the onset of clipping. When low, it
indicates that the level of the input signal has overloaded the amplifier resulting in increased distortion
at the output. The OVRLDB signal can be used to control a distortion indicator light or LED through a
simple buffer circuit, as the OVRLDB cannot drive an LED directly. There is a 20K resistor on chip in
series with the OVRLDB output.

T r i p a t h T e c h n o l o g y, I n c . - T e c h n i c a l I n f o r m a t i o n

TC2000 KLI/1.1/12-03

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 or 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 PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE
SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN CONSENT OF THE
PRESIDENT OF TRIPATH TECHNOLOGY 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 to 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.

For more information on Tripath products, visit our web site at: www.tripath.com

C o n t a c t I n f o r m a t i o n

T R I P A T H T E C H N O L O G Y , I N C

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408.750.3000 - P
408.750.3001 - F

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Part Number TC2000