C =

i

1

2

Z f

p

i

c

f

=

c

1

2

Z C

p

i

i

-3dB

f=

1

2

Z C

p

i

i

IN

Input

Signal

TPA3110D2

www.ti.com

SLOS528E – JULY 2009 – REVISED NOVEMBER 2015

Typical Applications (continued)

10.2.1.1 Design Requirements

For this design example, use the parameters listed in Table 4.

Table 4. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Power supply

8 V to 26 V

High > 2 V

Shutdown, gain, and PBTL controls

Low < 0.8 V

Speaker impedance BTL

4 to 8

Ω

Speaker impedance PBTL

2 to 8

Ω

10.2.1.2 Detailed Design Procedure

10.2.1.2.1

Input Resistance

Changing the gain setting can vary the input resistance of the amplifier from its smallest value, 9 k

Ω ±20%, to the

largest value, 60 k

Ω ±20%. As a result, if a single capacitor is used in the input high-pass filter, the –3 dB or

cutoff frequency may change when changing gain steps.

Figure 42. Input Impedance of the TPA3110D2

(2)

10.2.1.2.2

pass filter with the corner frequency determined in Equation 3.

(3)

reconfigured as Equation 4.

(4)

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