Other Parts Discussed in Thread: TPA2005D1, TPA2011D1
In our product, Class D Audio Power Amplifier "LM 48310" is used.
However, when our customers are using it, this amp is often broken.
The broken symptom is the following.
The impedance with the GND of the "OUTA" and "OUTB" output will be lowered.
The impedance of the broken IC is less than 30 Ω.
The impedance of a normal IC is several tens kilo Ω or more.
As a result, the overcurrent protection works and no sound don't work out.
For some reason, overvoltage or overcurrent may have occurred at the output terminal of IC.
I am in trouble because I can not understand the cause of the failure.
Attachment is a circuit diagram around "LM48310".
I would like to get advice for understanding the reason.
We are using in the following condition.
-Power supply voltage is 5.3 V
-Speaker impedance is 4Ω
-Maximum output is 3.7W (36% distortion)
-It is always connected to the speaker inside the product
I am worring about the following.
-Is it better to have diodes on OUTA and OUTB terminal for voltage clamping between VDD and between GND?
(The overshoot and undershoot waveform are looked on oscilloscope display.)
-"/SD" is controlled when the sound output.5280.Book1.xlsx
Are there any constraints on timing, including the power-on timing?
-Are there any conditions related to variations in impedance values of 4ohm speakers?
-Since the amplifier output Is used at the maximum, the signal Is clipped.
Is there anything to do with it?
-The cable used to connect with the speaker is about 20 cm.
Are there length requirements?
