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STA518A

3

TECHNICAL INFO:

The STA518A is a dual channel H-Bridge that is able to deliver 50W per channel (@ THD=10% RL = 8Ω,

VCC = 29V) of audio output power in high efficiency.

The STA518A converts both DDX and binary-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 pro-

tection circuitry.

In DDX mode, two logic level signals per channel are used to control high-speed MOSFET switches to connect

the speaker load to the input supply or to ground in a Bridge configuration, according to the damped ternary

Modulation operation.

In Binary Mode operation , both Full Bridge and Half Bridge Modes are supported. The STA518A includes over-

current and thermal protection as well as an under-voltage

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

Figure 7. STA518A Block Diagram Full-Bridge DDX® or Binary Modes

Figure 8. STA518A Block Diagram Binary Half-Bridge Mode

3.1 Logic Interface and Decode:

The STA518A power outputs are controlled using one or two logic level timing signals. In order to provide a prop-

er logic interface, the Vbias input must operate at the dame voltage as the DDX control logic supply.

3.2 Protection Circuitry:

The STA518A includes protection circuitry for over-current and thermal overload conditions. A thermal warning

pin (pin.28) is activated low (open drain MOSFET) when the IC temperature exceeds 130°C, in advance of the

thermal shutdown protection. When a fault condition is detected , an internal fault signal acts to immediately

disable the output power MOSFETs, placing both H-Bridges in high impedance state. At the same time an open-

drain MOSFET connected to the fault pin (pin.27) is switched on.

There are two possible modes subsequent to activating a fault:

Logic I/F

and Decode

Left

H-Bridge

Protection

Circuitry

INL[1:2]

INR[1:2]

PWRDN

OUTPL

FAULT

VL

TRI-STATE

OUTNL

OUTPR

OUTNR

TWARN

Regulators

Right

H-Bridge

Logic I/F

and Decode

LeftA

‰-Bridge

Protection

Circuitry

INL[1:2]

INR[1:2]

PWRDN

OUTPL

FAULT

VL

TRI-STATE

OUTNL

OUTPR

OUTNR

TWARN

Regulators

RightA

‰-Bridge

LeftB

‰-Bridge

RightB

‰-Bridge