LM4562: Bypassing/Decoupling caps

Giuseppe Gerla

Part Number: LM4562

Hi TI team

I would use the LM4562 in my "balanced control volume" project. I have several stages for each channel, so I'm using 5 chips in total. The board will have +15/-15V generated with LM7815/7915.

For LM4562 chips, on each power pin (VCC and VEE) I would use very close to the pin a X7R cap in parallel with an electrolitic cap to reduce the noise.

My question/doubt is about the value of these caps. On the chip datasheet there are 2 different diagrams. In figure 110 there is just one cap of 47uF on each power rail. Instead in figure 113 there are 2 caps in parallel one of 10uF and one of 0.1uF.

So my question is which are the right values to use?

What happen if I use bigger caps? For example 100uF and 0.47uF?

Thanks

Giuseppe

over 3 years ago

0 Ivan Salazar over 3 years ago

TI__Guru* 95355 points

Hi Giuseppe,

I would suggest to use 2 capacitors, 10uF or 47uF along with a 0.1uF.
The big capacitor is useful as reservoir for supply voltage droops, and the small one acts as short circuit to GND for high frequency transients on the supply.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

0 Giuseppe Gerla over 3 years ago in reply to Ivan Salazar

Prodigy 30 points

Ok, thanks for your answer.

How can I select 10uF or 47uF?

Which is the suggested type for both caps? For the bigger one is it ok electrolytic or tantalium cap? For the small one is it ok X7R type or I have to select something else?

Regards

0 Ivan Salazar over 3 years ago in reply to Giuseppe Gerla

TI__Guru* 95355 points

Giuseppe,

Usually ceramic capacitors are recommended although you can use electrolytic. Tantalum caps are not recommended unless otherwise noted (not this case).

Either 10uF or 47uF would be OK, higher capacitance means it will discharge/charge slower, as mentioned above this can help with supply voltage droops.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

0 Giuseppe Gerla over 3 years ago in reply to Ivan Salazar

Prodigy 30 points

Thank you very much for your help

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LM4562: Bypassing/Decoupling caps