July 1994

5

Philips Semiconductors

Preliminary specification

2 x 22 W BTL car radio power amplifier

with diagnostic facility

TDA1551Q

FUNCTIONAL DESCRIPTION

The TDA1551Q contains four identical amplifiers with differential input stages (two inverting and two non-inverting) which

can be used in SE or BTL applications. The gain of each amplifier is fixed at 20 dB for SE and 26 dB for BTL. The device

In the write mode the device can be switched to either the sleep condition (low sleep current of 0.6 mA typ.), the MUTE

condition or the ON condition.

In the read mode an 8-bit status word is available. Data bits D0 to D3 contain status information of each of the 4 outputs.

If the device is switched to the ON or MUTE condition and there is a short-circuit at one or more outputs, the power

transistors will be outside their safe operating area consequently one or more bits of D0 to D3 will be HIGH. Bits D0 to

D3 are LOW when in the normal safe operating area. Bit D4 is normally LOW if one or more channels reaches the clipping

level D4 will go HIGH. Bit D5 is normally LOW, if the crystal temperature reaches 150

°C D5 will go HIGH. After a

read. When pin 9 is LOW the device will switch OFF and the supply current will be reduced to 0.1 mA (max.).

Fig.3 Thermal equivalent resistance network.

handbook, halfpage

virtual junction

4 K/W

0.8 K/W

0.1 K/W

6

8

10

12

MLA009