Philips Semiconductors

TDA8944J

2 x 7 W stereo BTL audio amplifier

Product specification

Rev. 02 — 14 February 2000

4 of 21

9397 750 06861

© Philips Electronics N.V. 2000. All rights reserved.

8.

Functional description

The TDA8944J is a stereo BTL audio power amplifier capable of delivering 2

× 7W

output power to an 8

Ω load at THD = 10%, using a 12 V power supply and an

external heatsink. The voltage gain is fixed at 32 dB.

With the three-level MODE input the device can be switched from ‘standby’ to ‘mute’

and to ‘operating’ mode.

The TDA8944J outputs are protected by an internal thermal shutdown protection

mechanism and a short-circuit protection.

8.1 Input configuration

The TDA8944J inputs can be driven symmetrical (floating) as well as asymmetrical.

In the asymmetrical mode one input pin is connected via a capacitor to the signal

ground which should be as close as possible to the SVR (electrolytic) capacitor

coupling capacitors for both pins are necessary.

The input cut-off frequency is:

(1)

(2)

As shown in Equation 1 and 2, large capacitor values for the inputs are not

minimized. This results in a good low frequency response and good switch-on

behaviour.

Remark: To prevent HF oscillations do not leave the inputs open, connect a capacitor

of at least 1.5 nF across the input pins close to the device.

n.c.

13

not connected

OUT2

−

14

negative loudspeaker terminal 2

GND2

15

ground channel 2

16

supply voltage channel 2

OUT2+

17

positive loudspeaker terminal 2

Table 3:

Symbol

Pin

Description

f

icut

off

–

()

1

2R

i

C

i

×

()

–

-------------------------------

=

f

i cut

off

–

()

1

245

10

3

×

220

×

10

9

–

×

()

–

-------------------------------------------------------------------

16 Hz

==