Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

AUX INPUTS - PERMANENT DIAGNOSTIC

Agnd

Short to GND det. (above this

limit, the Audio Output is

considered in Short Circuit to

Vs) This condition must be true

for a time higher than Tdel

High side driver ON

0.75

V

Aol

Open load det. (voltage across

the sensing resistor. Below this

limit the Aux pin is considered in

Open Load condition)

This condition must be true for a

time higher than Tdel

0.085

V

Anop

Normal Operation det. (Voltage

across the sensing resistor.

Within these limits the load

resistance connected to the Aux

pin is considered correct)

0.125

0.5

V

PERMANENT DIAGNOSTIC - ACQUISITION TIME DELAY

Tdel

Acquisition time delay - The

fault is considered true if the

fault condition are present for

more than Tdel without

interruption

2s

PERMANENT DIAGNOSTIC - WARNING PIN

Vsat

Saturation voltage on pin 5

Sink Current at Pin 5 = 1mA

1

V

ADDRESS SELECT

Voltage on pin 4

Address 0100010X

1.5

V

Address 0100011X

3

5

V

I

Clock Frequency

400

KHz

Input Low Voltage

1.5

V

InputHigh Voltage

3

V

Sat Voltage at pin 2

Sink Current at Pin 2 = 5mA

1.5

V

ELECTRICAL CHARACTERISTICS (continued)

WORKING PRINCIPLES

Turn-on diagnostic - CH1, CH2, CH3, CH4, CH5 - Shorted load/open load detection

To detect a short across the load or an open load, a subsonic current pulse is generated. The infor-

mation related to the status of the outputs are measured and memorized at the top of the current

pulse (tm in fig.1). The current is sourced by the positive pins (CH1+,...CH5+) and it is sunk by the

corresponding negative pins (CH1-,...CH5-).

Isink and Isource are depending on the external resistor Rcs. The minimum allowed value for Rcs is

1.65KOhm. The relationship among Isink, Isource and Rcs is the following:

Isink = (3.3/Rcs) x 11

Isource = 1.5 x Isink

I(mA)

D97AU571

Figure 1.

TDA7476

4/15