Shockproof mounting of Discrete Op-Amps ?

[jdbakker]

Hi all,

Are there any tried&true methods of securing a 990/2520-type discrete op-amp to a PCB? None of the usual suspects have mounting holes, and I would like to keep my DOAs socketed (rather than soldered down). I can always McGyver something together out of tie wraps and duct tape, but I suspect there must be a more elegant way.

Thanks,

JDB.
[getting the 990-show on the road]

 

[mikep]

I just dealt with that problem myself. first thought was to stuff the components right onto the main PCB, ive seen some bryst0n products that do this. unweildy for protos though. I decided to develop my own footprint. I settled on a SIP arangement, sort of like the GeeML opamp but different.

also, for a shockproof "mastic" you cant do better than plumber's goop. seriously. a judicious dab of that in the right place will hold the opamp in, withstand alot of heat and vibration, and be easy to remove.

 

[jdbakker]

[quote author="mikep"]I just dealt with that problem myself. first thought was to stuff the components right onto the main PCB, ive seen some bryst0n products that do this. unweildy for protos though. I decided to develop my own footprint. I settled on a SIP arangement, sort of like the GeeML opamp but different.[/quote]
That will work (and all subassemblies that I design do have mounting holes), but I specifically want to be able to use existing DOAs like the 990.

Now I could design a go-between board with mounting holes and solder the DOA to that, but that only introduces more mechanical interfaces (and it would stop me from swapping DOAs between different pieces of equipment).

JDB.

 

[tomcat]

Two holes on the main pcb beide the opamp and some wire or cable binder (forgot the english word, the plastic stuff to put cables together). Works only on potted opamps.

Or use some heat glue. Can be removed if needed and holds up very well.

 

[clintrubber]

Could imagine that some clip exists somewhere, just as for tubes.

 

[tomcat]

If you want to do it hardcore i have another idea (stolen from the car batteries). Again works only with potted opamps.

You take a short strip of metal or plastic with one hole on each end (length=width of the opamp + space for the holes, so ~ 10mm more) , lay it over the opamp and screw it down to the main pcb with studs (you need holes in the main pcb).

So you can exchange without removing the main pcb, just two screws to loosen.

(maybe over the top :wink: )

 

[mikeyB]

If you got space - drill two 3mm holes on opposing sides of opamp. Fix a mounting post in each side - pcb standoffs etc. - that are higher than your tallest op amp. Use an offcut of pcb or some plate/board that sits over the top od the opamp and screws into the 3mm posts. you can cushion the opamp with some self adhesive form strip(draught excluder) if the posts are slightly taller

 

[jdbakker]

Thanks all.

To summarize: there are no universal, generally accepted ways of shock proofing an existing 990/2520-type DOA. On the other hand, several MacGyver-style hacks can be thought up to keep them in place.

Thanks again,

JDB.