Small LTC6655 Voltage Reference board

[Wirehead]

Hi All,

I've made a small board for an LTC6655 ref (any voltage you want) and it works pretty good. I've taken into account most of the datasheet recommendations in regards to grounding, ground planes, sense wire, decoupling, output cap selection.
In regards to that output cap (I've used a 10uF metalized polyester cap), here's what the datasheet says:

• ESR less than 0.1 Ohm @ 100kHz
• No X7R due to piezoelectric effect
• For very low noise, film caps should be used
• Between 2.7uF and 100uF

Some other items related this reference from the datasheet:

• Stiffer PCB's are preferred (Oshpark is pretty good)
• Mount it near the edge of the board (not perfect in my case, but it's a really small board)
• Pin4 is the actual ground, star grounding preferred
• Power and ground planes should be omitted under the voltage reference (also reduces thermocouple effects)

For all those that would like to give it a go, I've included the gerbers, they work out fine for OSHPark and the likes.

I'm in the progress of buying some calibrated Bench DMM's; so for now, you'll have to do with a shot of a VC99 (I can hear people screaming already ; but hey, It's bang on)

[branadic]

You better have used LTC6655-LS8 instead of MSOP package.

[Wirehead]

Yes, the LS8 package is better; but you need to reflow it, this package can still be soldered "the old way". I can make a PCB / gerber for the LS8 package if you want to? I'll add in the slots as well

[branadic]

With some experience soldering of the LS8 package by hand is no problem whatsoever.
Anyway, I don't need a reference board and if I would design it in a different way.