TDA8932BT View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

Manufacturer

TDA8932BT

Class-D audio amplifer

NXP Semiconductors. 

NXP Semiconductors

TDA8932B

Class-D audio amplifier

The 3 dB cut-off frequency is equal to:

f –3dB = -2---π-----×----R----1L----×-----C-----s--e-

(7)

Where:

f-3dB = 3 dB cut-off frequency (Hz)

RL = load impedance (Ω)

Cse = single-ended capacitance (F); see Figure 36

Table 15 shows an overview of the required SE capacitor values in case of 60 Hz, 40 Hz

or 20 Hz 3 dB cut-off frequency.

Table 15. SE capacitor values

Impedance (Ω)

Cse (µF)

f-3dB = 60 Hz

4

680

6

470

8

330

f-3dB = 40 Hz

1 000

680

470

f-3dB = 20 Hz

2 200

1 500

1 000

14.5 Gain reduction

The gain of the TDA8932B is internally fixed at 30 dB for SE (or 36 dB for BTL). The gain

can be reduced by a resistive voltage divider at the input (see Figure 10).

audio in

R1

470 nF

R2

R3

470 nF

100

kΩ

001aad762

Fig 10. Input configuration for reducing gain

When applying a resistive divider, the total closed-loop gain Gv(tot) can be calculated by

Equation 8 and Equation 9:

Gv(tot) = Gv(cl) + 20log -R---E----Q----+-----R(---RE----Q1----+-----R----2----)

(8)

Where:

Gv(tot) = total closed-loop voltage gain (dB)

Gv(cl) = closed-loop voltage gain, fixed at 30 dB for SE (dB)

REQ = equivalent resistance, R3 and Zi (Ω)

R1 = series resistor (Ω)

R2 = series resistor (Ω)

TDA8932B_4

Product data sheet

Rev. 04 — 18 December 2008

© NXP B.V. 2008. All rights reserved.

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