LM4670 stops oscillating

Fabrizio Raul Martinez Barragan

Other Parts Discussed in Thread: LM4670, TPA2034D1

Hi !

I'm working with the LM4670.
The output stops oscillating frequently , sometimes Vo2,Vo1 or both.
So the speaker get just pure dcv.

It happens with the input tied to gnd also with audio signal.

-I tried with a 330 ohms resistor as load and it happened again.

Single ended input.
Vsupply 3.2v
Load = 8 ohms

Vo1-Vo2 scope capture attached.

Regards!!

Any advise ?

over 10 years ago

0 Don Dapkus over 10 years ago

TI__Guru**** 189399 points

Hi, Fabrizio,

This type of behavior may be caused by the fact that it appears you have the SHUTDOWN terminal floating, poor PCB layout, poor power supply decoupling, or excessive capacitive loading on the outputs.

Please check these items to see if the operation improves.

This device is also quite old, you may want to consider one of our newer devices like TPA2034D1 family (2032, 2033, 2034)

-d2

0 Fabrizio Raul Martinez Barragan over 10 years ago in reply to Don Dapkus

Prodigy 30 points

Hi Don!

Ty for reply.

I'll do a double check on layout.

regards!

0 Fabrizio Raul Martinez Barragan over 10 years ago in reply to Fabrizio Raul Martinez Barragan

Prodigy 30 points

Hi
Now it's working good.
I assume it was the pcb prototype.

Thanks !

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LM4670 stops oscillating