Philips TDA1563Q

2000 Feb 09 20

Philips Semiconductors Product speciﬁcation

2× 25 W high efﬁciency car radio power

ampliﬁer TDA1563Q

APPLICATION NOTES

Example of the TDA1563Q in a car radio system

solution

The PCB shown here is used to demonstrate an audio

system solution with Philips Semiconductors devices for

caraudio applications. The board includes the SAA7705H:

a high-end CarDSP (Digital Signal Processor), the

TDA3617J: a voltage regulator providing 9 V, 5 V and

3.3 V outputs, and two TDA1563Qs to provide four 25 W

poweroutputs. A complete kit (application report, software

anddemo board) of this “car-audio chip-set demonstrator”

is available.

The TDA1563Q is a state of the art device, which is

different to conventional amplifiers in power dissipation

because it switches between SE mode and conventional

BTL mode, depending on the required output voltage

swing.As a result, the PCB layout is more critical than with

conventional amplifiers.

NOTESAND LAYOUT DESIGN RECOMMENDATIONS

1. TheTDA1563Q mutes automatically during switch-on

and switch-off and suppresses biasing clicks coming

fromthe CarDSP circuit preceding the power amplifier.

Therefore, it is not necessary to use a plop reduction

circuitfor the CarDSP. To mute or to enlarge the mute

time of the system, the voltage at the mode pin of the

amplifiers should be kept between 2 V and 3 V.

2. The input reference capacitor at pin 3 is specified as

1µF but has been increased to 10 µF to improve the

switch-onplop performance of the amplifiers. By doing

this, the minimum switch-on time increases from

standby,via internal mute, to operating from 150 ms to

600 ms.

3. It is important that the copper tracks to and from the

electrolytic capacitors (SE capacitors and supply

capacitors) are close together. Because of the

switching principle, switching currents flow here.

Combining electrolytic capacitors in a 4-channel

application is not recommended.

4. Filters at the outputs are necessary for stability

reasons. The filters at output pins 8 and 10 to ground

should be connected as close as possible to the

device (see layout of PCB).

5. Connect the supply decoupling capacitors of 220 nF

as closely as possible to the TDA1563Qs.

6. Place the tracks of the differential inputs as close

togetheras possible. If disturbances are injected at the

inputs,they will be amplified 20 times. Oscillation may

occur if this is not done properly.

7. The SE line output signal of the CarDSP here is

offered as a quasi differential input signal to the

amplifiers by splitting the 100 Ω unbalance series

resistanceinto two 47 Ωbalanced series resistances.

Thereturn track from the minus inputs of the amplifiers

arenot connected to ground (plane) but to the line out

reference voltage of the CarDSP, VrefDA.

8. The output signal of the CarDSP needs an additional

1storder filter. This is done by the two balanced series

resistances of 47 Ω (see note 7) and a ceramic

capacitor of 10 nF. The best position to place these

10 nF capacitors is directly on the input pins of the

amplifiers.Now, any high frequency disturbance at the

inputs of the amplifiers will be rejected.

9. Only the area underneath the CarDSP is a ground

plane. A ground plane is necessary in PCB areas

where high frequency digital noise occurs. The audio

outputs are low frequency signals. For these outputs,

itis better to use two tracks (feed and return) as closely

as possible to each other to make the disturbances

commonmode. The amplifiers have differential inputs

with a very high common mode rejection.

10. The ground pin of the voltage regulator is the

reference for the regulator outputs. This ground

referenceshould be connected to the ground plane of

the CarDSP by one single track. The ground plane of

theCarDSP may not be connected to “another” ground

by a second connection.

11. Prevent power currents from flowing through the

ground connection between CarDSP and voltage

regulator. The currents in the ground from the

amplifiersare directly returned to the ground pin of the

demo board. By doing this so, no ground interference

between the components will occur.