CONNECTION AND OPERATION

The following PCB image shows the connections

required for correct operation of the ZXCD50STEVAL

board. Simple connector blocks are provided to enable

easy connection of the supply voltage, audio inputs

and speaker outputs.

Power connection

The ZXCD50STEVAL requires a single positive supply

voltage:

25V @ approximately 2.3A for 50W music into 4

Note: 8

speakers can be used in this application. In this case a 25V bridge

supply will result in an output power of 25W music. If this is required then

C2/102 should be removed to maintain a flat frequency response.

The supply should not exceed 25V and must not be less

than 13V to ensure correct operation of the amplifier.

Ensure the correct polarity of the supply applied.

Audio input

The ZXCD50STEVAL requires a single ended audio

input per channel as follows:

The input impedance is 18k .

Input signal amplitude required for full output power is

approximately 2.5V peak to peak.

Speaker connection

4

speakers may be connected to the board as shown.

The correct polarity connection of the speakers is

essential to avoid phasing errors.

Note: 8

speakers can be used in this application. If this is required then

C2/102 should be removed to maintain a flat frequency response.

Over current protection is provided on the board,

which prevents

damage to the circuit with shorts from the speaker to ground or across the

speaker.

EVALUATION BOARD DESCRIPTION AND

OPERATION

The top copper , bottom copper and silk screen ID

overlay are shown in figure 1,2 and 3.

The ZXCD1000 is available in a 16-pin exposed pad

QSOP package. The exposed pad on the underside of

the package is soldered down to an area of copper on

the PCB, to function as a heatsink. To further assist heat

dissipation, the PCB has plated through vias

connecting to an area of copper on the underside of the

board.

The MOSFETS required on the board are Zetex ZXM64

series HDMOS parts. These SOT223 parts are required

to handle the power dissipation in the amplifier with a

50W music load.

The regulator transistors on the board are ZTX692B,

E-Line devices. These devices are required to supply

the 12V rail to the channels from the board input

voltage which is the 25V bridge supply.

The inductors in place on the board have been selected

for their excellent linearity and low losses. These

components ensure minimal distortion is introduced in

the recovered audio signal across the full power band.

The speaker is connected as a Bridge Tied Load (BTL).

This means that both sides of the speaker are driven

from the Output Bridge and therefore neither side of

the speaker connects to ground. This allows maximum

power to be delivered to the load, from a given supply

voltage.

ZXCD50STEVAL

ISSUE 1 - JULY 2002

2

Audio input

Channel A

Audio input

Channel B

Mute

Power connection

Speaker connection

Channel A

Speaker connection

Channel B