Packaging question: connecting to a butterfly LD package

Like this?

Horrible package!

John

Yes, that's the one--there's a highish power thermoelectric cooler inside, so you have to mount the package right to the heat sink, with the usual CTE and vibration worries that entails. Here's one shown mounted on a board.

My problem is that there isn't space round the sides--once the board cutout is made, there's no meat left. We could glue little breakout boards to the sides of the package, but, well, yecch.

Cheers

Phil Hobbs

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lex

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could you bend the pins 90deg up and have a board on top? could even use some spacers on the screws to mount the board so it isn't held by the pins

-Lasse

I was going to suggest exactly that, but if you're out of width, never mind.

You could snip the pins short or fold them 90 degrees and run wires to pads on a pcb above the package. Later convert that to a u-shaped flex.

How many of the pins do you need to connect to?

I hate packages like this. The RF boys love to do metal blocks with RF feedthrus sticking out all over the place, too, which forces you to solder wires.

John

board.http://communities.mentor.com/mgcx/servlet/JiveServlet/download/23101...

That's a reasonable possibility. A colleague just showed me a board with a flex core, so we might be able to make something that would have a little FR4 wing on each side, with the leads soldered in PTHs, and connect via integral flex.

If I can fit all the driver stuff in the available space, I'll probably do the board-on-top thing more or less as you suggest. A little 32-thou board won't weigh much, and if the mounting holes are some distance from the pins, it'll flex enough that we won't have gross compressive stress in the pins.

Cheers

Phil

Been there, and it wasn't pretty because we had to do it by hand (too small a volume in production). Litz wires ... tssss .. solder to pin ... tssss .. solder to board ... next ..

The real way to do this would be rigid-flex. A slot in the board so the butterfly pack sticks up to the bottoms of the pins are roughly aligned with board center. The last .200" (or more) of board on each side are flex. Have it kinked or waved a wee bit so sideways stress is tolerated by these links.

You might want to think about doing the whole board in flex. Got to price that out first though. Even then, have it kinked or wave-shaped along the butterfly because in contrast to SO or TSSOP a butterfly has no sideways pin compliance whatsoever.

And don't forget them thar holes for them thar hex wrenched fer gitten dem screws real tight ;-)

TE cooler in a downhole (oil patch) app? Toss it and use best thermal coupling to the Z-chassis..

Rebuild the package around it. This is not a simple low-powered device, especially if complicated by a TEC.

RL

Nope, doomed. DFB telecom lasers go south if they get much above room temperature, and this is a high stability application--wavelength stability of 100 parts per trillion over hours. There's a bunch of secret sauce in the temperature control part.

Cheers

Phil Hobbs

Not possible--it has to fit inside a 1-3/8 inch cylinder. But that's what makes it fun.

Cheers

Phil Hobbs

Then how the heck can you get the whole thing to operate reliably to