E-TDA7476 STMicroelectronics, E-TDA7476 Datasheet - Page 8

• Manufacturer Part Number: E-TDA7476
• Description: IC PROCESSOR RADIO DIAGN 24-SOIC
• Manufacturer: STMicroelectronics
• Type: Audio Processorr

Specifications of E-TDA7476

• Applications: Automotive Audio
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Operating Temperature (min): -40C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TDA7476
Permanent diagnostic - AUX1, AUX2 - Short circuit to GND and open load
Timing
Note: any (positive) spread of the capacitor value must be added. The relation to be used to determine Twait1
from the value of CT according to the following:
For bridge or bridge equivalent devices (figg.5,6), Ct = 10 F will be enough.
TURN-ON DIAGNOSTIC - THRESHOLDS
CH1, CH2, CH3, CH4, CH5
8/19
The detection mode of the auxiliary inputs is equal to what is in place during turn-on, but the fault must
be lasting without interruption for more than 2 seconds.The warning pin is pulled down only in case of
short to GND. This is to avoid that this pin remains permanently to 0 level if one or both AUX outputs of
the car radio are unused.
From the byte "ADD1" to the byte "ADD2" the mP must wait a period Twait1(see Software Specification)
that is depending on the timing capacitor CT according to the following table (Twait1> tm, max):
After the byte "ADD2" the power amplifier can be switched-on. In some cases, the P has to wait until
the current pulse is finished (Twait2). This time (ts in fig.1) is given by:
Output voltage during test. (The power amplifier must be in ST-BY mode).
Voltage across the load during test. (The power amplifier must be in ST-BY mode).
Note: some faults can mask others if they are present at the same moment on the same channel:
- If there is a short to GND and an open load on the same channel, the TDA7476 gives information only
- The short circuit to GND masks any short circuit across the load.
- The short circuit to Vs masks any short or open load.
about one of them, depending on the wire on which the short circuit is present.
0V
0V
S.C. across Load
CT ( F)
S.C. to GND
100
3.3
4.7
10
22
47
Twait1 > tm, max = (130 · CT/10 F)ms
5mV
Twait2 > ts, max = (140 · CT/10 F)ms
0.8V
x
x
22mV
1.2V
Normal Operation
Normal Operation
220mV
V
S
-1.2
x
x
550mV
V
S
-0.6V
Open Load
S.C. to Vs
tm max (ms)
D97AU631A
D96AU502B
1300
130
290
620
45
65
V
V
S
S