STA533WF

Applications information

Doc ID 17658 Rev 2

7/15

3

Applications information

The STA533WF is a dual-channel H-bridge audio power amplifier that can deliver 20 W per

channel into 8

The STA533WF converts both FFX and binary-logic-controlled PWM signals into audio

power at the load. It includes a logic interface, integrated bridge drivers, high-efficiency

MOSFET outputs and thermal and short-circuit protection circuitry.

In FFX mode, two logic-level signals per channel are used to control the high-speed

MOSFET switches which drive the speaker load in a bridge configuration, according to the

damped ternary modulation operation.

In binary mode, both full-bridge and half-bridge modes are supported.

The STA533WF includes overcurrent and thermal protection as well as an undervoltage

lockout with automatic recovery. A thermal warning status is also provided.

Figure 4.

Block diagram for FFX or binary modes

Figure 5.

Block diagram for binary half-bridge mode

Logic interface and decode

The STA533WF power outputs are controlled using one or two logic-level timing signals. In

order to provide a proper logic interface, pin VL must have the same voltage as the PWM

input signal.

Logic

interface

and

decode

OUTPL

OUTNL

Left

H-bridge

Protection

circuit

Regulators

OUTPR

OUTNR

Right

H-bridge

INL[1,2]

VL

PWRDN

TRISTATE

FAULT

THWARN

INR[1,2]

OUTPL

Left A

bridge

Logic

interface

and

decode

Protection

circuit

Regulators

INL[1,2]

VL

PWRDN

TRISTATE

FAULT

THWARN

INR[1,2]

OUTNL

Left B

bridge

OUTPR

Right A

bridge

OUTNR

Right B

bridge