tk2070 Tripath Technology Inc., tk2070 Datasheet - Page 14

• Manufacturer Part Number: tk2070
• Description: Stereo 70w 4ohm Class-t Digital Audio Amplifier Driver Using Digital Power Processing Dpp Technology
• Manufacturer: Tripath Technology Inc.

For example, using a TK2070 with the following external components,
Please note that OUT1P (OUT2P), as shown in the Application/Test Diagram, is out of phase with
respect to the input signal. This phase reversal can be eliminated by connecting OUT1N and OUT2N
to the positive terminal at the speaker.
I n p u t S t a g e D e s i g n
The TC2001 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.
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
I n p u t C a p a c i t o r S e l e c t i o n
C
frequency pole. Typically this pole is set below 10Hz. C
where:
14
I
can be calculated once a value for R
R
R
R
R
R
A
C
f
A
P
I
F
FBB
FBC
V
I
V
I
= 20k:
= Input low frequency pole (typically 10Hz or below)
= Input resistor value in ohms.
= 20k:
I
INPUT
TK2070
must be followed as shown in Figure 1 for a standard ground referenced input signal
= 1k:
= 11k:
2
S
1
f
INPUT1
INPUT2
STAGE
P
R
|
I
20k
20k

CI
CI
R
R
§
¨
©
F
I
11k
RI
RI
Figure 1: Input Stage
1k
RF
RF

1k
:
I
OAOUT1
INV1
INV2
OAOUT2
has been determined. C
)
BIASCAP
·
¸
¹
12
TC2001
V
V
AGND
AGND
-
+
+
-
V5
V5
I
is calculated according to:
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
I
and R
I
determine the input low
TK2070 – MC/2.1/10-03