Power Components and Surface Tension

Another Parts Library issue

Surface tension can be quite handy. For one thing, without surface tension, water bugs wouldn't be able to skip along the surface of a pond. They'd sink like a rock straight to the bottom and frogs wouldn't be able to eat them. The frog population would plummet and we all know what that means.

Another handy effect of surface tension is that it acts to help BGAs and QFNs to center themselves during reflow. This same effect can backfire on us though. Take a look at the TO-263 packaged regulator in the photo. By the way, the LM1086 really annoys me. Why in the world isn't it pin compatible with the ubiquitous 78XX regulator pinout? Yeah, I know it's a low-dropout but other low-dropout regulators use the standard pin out. What gives?

Anyway, what happened is that surface tension pulled the part up and nearly pulled the three legs off of their land pads. If not reworked, the legs won't be mechanically secure, they may not have sufficient current carrying capacity and if there are and mask imperfections, they are at risk of shorting to the copper fill area.

There are a couple of possible remedies here:

1. Mask off the top of the thermal pad so the part can't slide up that far.
2. If the pad needs to be fully exposed for better convection, just use a strip of soldermask as a solder dam. If you use this approach, don't forget to modify the paste layer so that no solder paste is spread above the mask dam.
3. Extend the thermal pad down so that when the body of the part is centered, the legs will still be appropriately located on their pads.

Duane Benson
What about newts?

The Maelstrom

I'm back from the maelstrom of back to back tradeshows so I should be able to get back to more regular posting. But there's a bit of a maelstrom going on here right now. You may have noticed the note on our home page that 24 and 48 hour turns are back ordered today and tomorrow. They will be Monday and Tuesday, the 19th and 20th also.

We've got some hefty maintenance going on right now. We're pretty busy these days so taking some of the equipment offline leaves our capacity temporarily reduced. I thought there was a recession going on or something. It certainly doesn't look like it based on the amount of work we're seeing.

Anyway, we'll be back up to full capacity on Wednesday, maybe sooner. Then we'll have the backorder situation with 24 and 48 hour turns again next Monday and Tuesday.

If you need fast turn today, tomorrow or next Monday or Tuesday, please call us at 866-784-5887.

Duane Benson

ESC - LeCroy

LeCroy, booth 642, had an eye catching display. They have a Nintendo Wii with Guitar Hero playing on it. That's cool on its own, but wouldn't be relevant except that they are probing the I2C with one of their GHz scopes.

It parallels a conference session they did: "How to Debug I2C Devices Using an Oscilloscope". We spoke with Dave, one of the guys who gave the talk. We watched him pay for a bit as he explained that his scope was showing the I2C communications coming from the key presses on the controller. Very nice.

Then he let me and my compatriot, Rocky play. First I tried it and got booed off the stage with on 21%. Then Rocky and I played against each other and he beat me 10,095 to 8,402.

That's me playing/humiliating myself on the guitar in the photo.

ESC - No, We're Not Done Yet

Day two is going okay and keeping us pretty busy. We've talked to a lot of folks and picked out our booth space for next year. We'll be in booth 3912 in the South hall. We'll be just inside the door, one row back.

I'm not sure the show is going well for everyone though. I ran across this booth that has been abandoned already. Myself, my feet are pretty sore and I'd like a nap, but it's still fun to be here.

Duane Benson
Two more hours...

ESC - My Mom Would Say...

She'd say "your going to electrocute yourself."

Duane Benson
We need more cables!

ESC - Luminary micro

I'm big on the robotic type applications. It fits too because robots are just embedded systems that move. Right?

Luminary Micro designs and manufactures Arm Cortex-M3 processors. I'm not familiar with the specific details for the Cortex-M3 implementation, but I do know that part of Luminary's reputation is good processor at a good price.

At the ESC here, they're showing off the power of their processors with some intelligent manipulator arms using their Arm processors. They're in booth 3010.

Duane Benson

ESC - RadiSys Robot demostration

I found another cool thing over at the RadiSys booth. They use an Intel Dual core processor and run half of it powered by embedded Windows and the other half of powered by with Linux. Dual core and dual OS. Neat.

Thier demo is a little robot that find a sign. You move the sign and it finds it. Find them in booth 1526.

Duane Benson

ESC - National Instruments

I spoke with Jamie at National Instruments, booth 1508, about just about the coolest way to distribute show premiums I've ever seen. They're showcasing a new version of LabView for Arm processors. It brings all of that power down to less expensive computing platforms.

I've used a variant of LabView in the Lego Robot system but this is real stuff. It does a great job of combining visual programming with lower level coding, like C.

I got a Twixt.

Duane Benson

Sunstone is Here Too

The show is on and engineers are starting to come by. We also have two folks here from our board fab partner, Sunstone Circuits. That's Lee and Nolan there. I'm not telling who is who. You have to stop by the booth for that information. (#1944)

Duane Benson
Smile. You're on Screaming Camera

ESC Go time!

We have a booth. We have staff. We're ready to go. The show starts in about ten minutes and we're jazzed up! Well, most of us are. I'm tired and hungry. I've had a chocolate chip cookie for breakfast. That's it.

By the way, it was a really good cookie. The place I got it from is on the back wall in the 1500 column. The might be sold out by the time you get there or maybe they won't be warm an gooey like the one I had was. Very yummy.

In a bit I'll take a walk around and see what's cool. I think there's more than in past years. Luminary Micro had a bunch of little robots. Outside, there was a robotic Giraffe and someone else had an automated system for dispensing booth give-aways.

Duane Benson
Feed me... Feed me...

ESC - Day 0.128

Well, I'm here and unlike in past years (here and here), ALL of my boxes are here too. We've got a bigger booth this year (#1944), at 10x20 instead of a 10x10 and we're also inside the hall for the first time. That's cool. I'll probably be done setting in up twenty minutes or so. Then I have a couple of hours to hang out and do whatever. Maybe I'll go check out the nearby Tech Museum.

Duane Benson
See (some of you) soon

On The Way To San Jose

A scene being repeated all over the West coast... I'm sitting in the airport waiting for my flight to San Jose. I had to get up at 4:00am to get here on time and I'm tired. I'll get down there in a couple of hours, set up the booth and then find a way to occupy myself for the evening.

I always like this show. It's refreshing to be surrounded by so many engineers and cool things going on at the other booth's. I hope to see you there - booth 1944. Read this post, and you can get a free pass to the show.

Duane Benson
I'm going to find some piece of mind...