TDA7803A datasheet(25/72 Pages) STMICROELECTRONICS

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DS12195 Rev 7

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TDA7803A

Functional description

6.1

Voltage regulators timing

Pins D3V3 and A3V3 are respectively digital and analog internal regulators outputs. The

D3V3 rises right after the STBY pin is at the logical value "1" and its rising time depends on

the filter capacitor; the minimum value suggested for this filter is 4.7 µF.

The A3V3 rises after any command that moves the amplifier from ECO - mode; the rising

time depends on the combined effect of the external capacitor on the pin and of an internal 2

ms ramp: if the capacitor value is 22 µF or lower, the internal ramp effect is dominant and

the rising time will be about 2 ms. On the other hand, when the capacitor has a higher value,

the rise time will be higher as well. The suggested value for this capacitor is 22 µF at least.

6.2

Turn-on diagnostic description

The turn-on diagnostic is triggered on the rising edge of bit IB4 D0 when IB7 D0 is "0". This

happens when the amplifier is in ECO - mode. It is possible to run one or more turn-on

diagnostic sequences according to the following procedure:

wait the previous cycle is over

read the data bytes DB1,DB2,DB3 and DB4

Please note that all these instructions must be sent while the amplifier is still in ECO - mode

(IB7 D0 = "0"), otherwise they won't be executed.

Turn-on diagnostic does not start if VCC is below 8 V or one of the muting condition is

present, (low battery mute, high voltage mute, PLL-unlock mute, thermal mute, hardware

pin mute).

Note:

The diagnostic enable bit (IB4 D0) must be set before the amplifier mode bit (IB7 D0).

DB1, DB2, DB3 must be read before DB4 (after DB4 is read the DB1-2-3-4 are reset).

The detected faults are here described:

Soft Short to GND: it detects the presence of a resistor (see Table 5 in “Turn-on diagnostic”

section) connected between an output and ground, which could result in a wrong open load

or short across load diagnostic result (causing an anomalous current consumption in some

cases).

Soft Short to VS: it detects the presence of a resistor (see Table 5 in “Turn-on diagnostic”

section) connected between an output and battery, which could result in a wrong open load

or short across load diagnostic result (causing an anomalous current consumption in some

cases).

Short to GND: it detects the hard connection between an output and ground. The value of

the short is able to pull the output between 1.5 V and ground.

Short to VS: it detects the hard connection between an output and battery. The value of the

short is able to pull the output between (battery - 1.5 V) and battery.

Short across the speaker: it detects the hard connection across the speaker that is below

a certain value. This value guarantees that the IC is able to drive any speaker configuration

within the range specified in the datasheet.

TDA7803A Datasheet(PDF) 25 Page - STMicroelectronics

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