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DIY Stompboxes => Building your own stompbox => Topic started by: paku5535 on August 21, 2012, 05:49:41 AM

Title: Direct substitute of CA3080....
Post by: paku5535 on August 21, 2012, 05:49:41 AM
hello guys,

Can i directly substitute ca3080 with LM13700 by taking appropriate pin(Pins of CA3080)? Or any modification require?? Actually I had one piece of CA3080, Which I burnt in short circuit and After making PCB i cannot even check whether the circuit is working properly...The only available chip is National LM13700...

Thank you
Title: Re: Direct substitute of CA3080....
Post by: Kesh on August 21, 2012, 09:52:45 AM
I'm guessing you read http://www.idea2ic.com/LM13600/UsingOTAs2.pdf which says it is a replacement but dual version and with bias diodes which you can leave unconnected.
Title: Re: Direct substitute of CA3080....
Post by: R.G. on August 21, 2012, 02:59:27 PM
If you ignore the distortion reduction diodes and the diode buffers, yes, it operates much the same way in a circuit. However, there is one other issue. The Iabc pin on the CA3080 will always be at one diode drop (0.45 - 0.7V) above the most negative supply pin. In the LM13700 and all other later OTAs, the current mirror input will sit at two diode drops (0.8 to 1.4V) above the most negative supply. In most circuits this makes no difference at all. However, there are some limited situations where it would make a difference.

But you're right, you are stuck with figuring out how to make an LM13700, NE5517, or CA3280 work.
Title: Re: Direct substitute of CA3080....
Post by: paku5535 on August 22, 2012, 06:01:43 AM
yea RG.....

thanks RG and Kesh for your reply......