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DIY Stompboxes => Building your own stompbox => Topic started by: GibsonGM on December 29, 2006, 01:01:46 AM

Title: Terminate unused opamps?
Post by: GibsonGM on December 29, 2006, 01:01:46 AM
IIRC, to terminate an unused opamp you should connect output to - input, and +input to ground, right?  I guess this keeps it from making noise or oscillating?  I'm going to have an unused section of TL064....
Thanks!
Title: Re: Terminate unused opamps?
Post by: zyxwyvu on December 29, 2006, 01:10:28 AM
A quick google search comes up with this link:

http://www.maxim-ic.com/appnotes.cfm/an_pk/1957 (http://www.maxim-ic.com/appnotes.cfm/an_pk/1957)

Basically, the method you mentioned is discouraged, and the recommended solution (which is very similar to yours) is to connect (-) and output, and bias (+) to half the supply voltage.

The page also mentions that it is important to do so, in order to reduce noise and supply current.
Title: Re: Terminate unused opamps?
Post by: petemoore on December 29, 2006, 01:11:08 AM
  I've heard of other ways.
 I used 1/2 of a dual for THOR, connecting pins 2,3,4, [grounding the -/+ inputs on the left side] an easy row to solder in, then used the right half for the circuit connections.
 Leaving pin one open...if the opamp's working right, this output should be at  0v, just like the inputs...that should 'hold it still'
 
Title: Re: Terminate unused opamps?
Post by: GibsonGM on December 29, 2006, 01:21:29 AM
Thanks guys...think I'll try + to Vb....making an off-board oscillator for my easyvibe, trying to get rid of the clicking oscillator...nothing else has worked, so this HAS to be it, LOL
:icon_cool: