TDA7493

Applications information

Doc ID 14570 Rev 6

15/30

5.5

Internal clock and external clock

The clock of the class-D amplifier can be generated internally or it can be synchronous with

the external clock. If two or more class-D amplifiers are used in the same system, it is better

to have all devices working at the same frequency. This is realized by using one TDA7493

as clock master and the others as slaves. All SYNCLK pins are connected together as

shown in Figure 8.

In master mode or with a single TDA7493, the output switching frequency is controlled by

the resistor connected to pin ROSC. The switching frequency is:

Note:

In slave mode, pin ROSC can be floating to force pin SYNCLK as input in order to accept the

master clock. The switching frequency in this mode is:

Figure 8.

Master and slave modes

Table 9.

Master and slave mode

Mode

Pin ROSC

Pin SYNCLK

Master

Output

Slave

Floating

Input

Master

Slave

ROSC

SYNCLK

SYNCLK

ROSC

Output

Input

TDA7493

TDA7493

100 nF

39 k

Ω