Where to buy op 27 opamps?

I am looking for op 27 or opa 27 opamps in TO 99 package.
I can't find them. Digikey tells me they are special order item and I have to buy 60. I don't need that many right now just want to try them in place of LM 301 opamps. Anybody here know where to get some?

Thanks

Hi,

Welcome to The Lab!

You may have trouble getting the TO99 package OP27 from regular sellers- it's usually only supplied to industrial and aerospace customers directly from the manufacturer.

Watch out if you are replacing the LM301 pin-for-pin with the OP27- the LM301 has a compensation capacitor strapped across pins 1 and 8, and if left in-circuit, this may cause problems with the internally-compensated OP27. Pins 1 and 8 on the OP27 are the offset-null.

If you're replacing the LM301 with the OP27, there is a way around the differing pin spacing- circular to DIL. Get one of these:

8-Pin DIL Wirewrap Socket

(links to picture)

These wirewrap sockets have nice long legs. You can bend them to fit the TO-99 holes in the board. Use a bit of 1mm silicone sleeving on the pins if need be. I've done this before and it worked a treat. Then just pop your regular 8-DIL into the socket. These wirewrap holders are also good for replacing other pinout IC's, as highlighted by Eddie Ciletti:



Handy!



Mark

Mark thanks for info on wirewrap socket didn't want to go that route, I didn't think it would look clean. May have to change my mind though,that way i can try different opamps. Thanks for heads up on comp cap on 301 I will remove before trying other opamps.

You know, you can buy a much tidier version of what is shown in that photo. I've got some here. It's Digi-Key part number A330-ND. It's on page 282 of the current Digikey catalog (T042). They call it a TO-8 to DIP adapter, but as far as I can tell TO-8 and TO-99 are the same thing, and I bought them to replace the metal-can LM301s in my UREI BL-40. These little adaptors are kind of expensive ($6.70 in qty 1) but if they do what you need done in small quantities, they're probably worth it.

Justin,

They're great little adaptors! I hadn't seen those in the UK. I'm sure you could DIY one very easily if you needed to- nice quality turned-pin 8-DIL socket on an etched pcb (just mark the layout for the TO-99 pins on the PCB and etch tracks to the 8-DIL pads) and then use those long PCB-pins for the TO-99 pins below the board. It'll make it worthwhile if you're replacing more than a couple- just etch a whole board of "adaptor boards".

Mark

FWIW, I had only intended to use the 14-pin wirewrap sockets for test purposes -- to convert two dual opamps to one RC-4136. For 8-pin conversions, a wirewrap socket works nicely and is cheap (if you can still find them).

ec

[quote author="ulysses"]You know, you can buy a much tidier version of what is shown in that photo. I've got some here. It's Digi-Key part number A330-ND. It's on page 282 of the current Digikey catalog (T042). They call it a TO-8 to DIP adapter, but as far as I can tell TO-8 and TO-99 are the same thing, and I bought them to replace the metal-can LM301s in my UREI BL-40. These little adaptors are kind of expensive ($6.70 in qty 1) but if they do what you need done in small quantities, they're probably worth it.

[/quote]

I have used those as well, although in some cases if the board I'm working with is too tightly packed with components, it might not fit.