STA533WF

Applications information

Doc ID 17658 Rev 2

9/15

Supply decoupling capacitors

To meet the performance figures given in this datasheet the STA533WF power supply must

be adequately filtered.

For this purpose capacitors connected from pins VCC1 to GND1 and from VCC2 to GND2

must be placed as close as possible to the related IC pins.

For reliability and optimum performance the following capacitors are suggested:

●

100-nF ceramic capacitor with lead length less than 2 mm, connected to the ground

plane and as close as possible to the GND pin

●

1-uF X7R (low ESR) capacitors.

connected to other ground pins, it is an internally generated supply.

connected to other supply pins, it is an internally generated supply.

Output filter

A passive 2nd-order filter is used on the STA533WF power outputs to reconstruct an analog

audio signal. The system performance can be significantly affected by the output filter

design and choice of passive components.

Filter designs for 4-

Ω and 8-Ω loads are shown in the applications circuits below.

Applications circuits

Figure 6 shows a typical full-bridge circuit for supplying 20 W + 20 W into 8-

Ω speakers with

Figure 7 shows a single-BTL configuration capable of supplying 40 W into a 4-

Ω load at

STA309A + STA533WF demo board.

For both applications circuits a PWM modulator is required as driver.