Op Amp Bypass

tom_pay

Member

• Dec 1, 2010

• #1

Hi

What does the bypass pin on an Op Amp do?

I understand that it is for decoupling. But decoupling what?

Is it basically like the capacitor that is put on the power lines of a PIC, just on a different pin to do something internally?

I'm sorry about my simple question, but I'm really confused.

Tom

 

1

#12

New Member

• Dec 1, 2010

• #2

Umm...yes...considering that I am guessing exactly which op-amp you are talking about.

 

EN0

Member

• Dec 1, 2010

• #3

So tom_pay (catch the word, fellas?), will you pay us to research this concept for you? C'mon now, it doesn't take much to google this! Start here.

I love that website! Don't you?

 

crutschow

Well-Known Member

Most Helpful Member

• Dec 1, 2010

• #4

I don't know of any op amps with a "bypass" pin. What op amp are you referring to?

 

J

Jaguarjoe

Member

• Dec 1, 2010

• #5

Are you talking about the capacitor such as the one between pins 1 & 8 on this IC?

https://www.electro-tech-online.com/custompdfs/2010/12/LM101A.pdf

Or are you talking about the capacitor such as the one from pin 7 to gnd on this IC?

https://www.electro-tech-online.com/custompdfs/2010/12/LM386.pdf

 

Last edited: Dec 1, 2010

audioguru

Well-Known Member

Most Helpful Member

• Dec 1, 2010

• #6

Yesterday he wrongly called an LM380 an opamp but instead it is a power amp with a "bypass" pin. Its datasheet describes that a capacitor on its bypass pin reduces power supply noise on its output. Then he asked why he can't filter the power supply noise by using a huge and expensive supply bypass capacitor instead of a little inexpensive one on the "bypass" pin.

 

tom_pay

Member

• Dec 1, 2010

• #7

Thanks for your help. I understand it better now.

Tom

PS I like the Google thing!!!