Confusing Double Measurements on Data Sheet

[Phrazemaster]

Hi, anyone have any idea why this data sheet drawing would have two different sets of measurements for many of the dimensions? Obvs there's the metric and imperial measurements, but I'm talking about the doubled measurements for each dimension.

It's doing my head in as I'm designing an enclosure for this phototransistor and can't figure out what the size actually is.

Yeah, I'll get the part in next week and I'll use calipers to scope it out, but until then, any ideas?

Thanks,

Mike

 

[ccaudle]

Looks like min/max dimension tolerances to me.

 

[Phrazemaster]

Looks like min/max dimension tolerances to me.

Thanks ccaudle. That's what I thought too, but since there's no notation about it, I don't know.

Plus the tolerances would be abysmal in that case...off as much as .5mm?

Any other ideas?

Thanks,

Mike

 

[JohnRoberts]

looks like min/max, easier to spec that way than with asymmetrical over/unders around a nominal.

JR

 

[ccaudle]

Plus the tolerances would be abysmal in that case...off as much as .5mm?

The dimensions that are that wide look to be notches stamped in the leads, and the dimension of the molded plastic. The more wiggle room the specs allow the longer they can go without having to replace the tooling, or the more flexibility in using different package sub-contractors.

 

[ruffrecords]

Tolerances i.e min and max values?

Cheers

Ian

 

[Phrazemaster]

Thanks everyone for the insights. It makes sense with what you all shared, and next week will tell the tale when I actually receive the parts. I'll post back here with a couple measurements for a laugh, but I'm sure you are all correct.

Thanks so much,

Mike