Interview with Eric Holland

Featured Engineer

Eric Holland

Eric Holland - Senior Electronics Design Engineer, Hacker, and Blogger

How did you get into electronics?

My younger brother and I loved LEGOs and we built some pretty elaborate castles. We would always make them without roofs, so you could move the minifigs from room to room. We also had all kinds of secret passageways and trap doors built into the castles as well. I remember going to Radio Shack and buying a pack of LEDs and stringing them all together and using them as torches that lit up our castles. I also remember wiring up a 555 timer to blink a couple LEDs for my LEGO fireplace. I had no idea how LEDs worked but I knew if you wired them up to a battery pack they would only light up when hooked up a certain way.

The Radio Shack Forrest Mims Engineer’s Mini-Notebooks and a 50-in-One Electrics Kit was probably my first taste at real electronics. I was lucky enough to go to a High School that had a couple electronics electives as well. We wired up a 3-way switch and etched our own PCBs to make an AC-DC power supply with a LM317. I actually still have that PSU and use it to power all my Guitar Effects stomp boxes.

Probably the biggest influence I had was in High School I took a several BASIC, Visual BASIC and C/C++ courses and the regular teacher was on medical leave, so a local Engineer came in and taught the C/C++ course. You could tell he loved being an Electrical Engineer and he encouraged me to go to college and get an EE degree.

What are your favorite hardware tools that you use?

I am in love with my Agilent Infiniium 4-Channel 1GHz MSO. The Mega Zoom feature is awesome. I can zoom out to 1 sec per division see the I2C or SPI lines toggling press the stop button and zoom right into each byte being transmitted. No need for fancy triggering when you can zoom in so far. I am also a huge fan of Metcal Soldering Irons; they are what I learned on when I was a Technician soldering SMT components and I haven’t found anything I like better.

What are your favorite software tools that you use?

We use Altium at work and even though it has its quirks I think it is one of the best PCB CAD tools on the market; I’ve used Orcad and Mentor’s PADs as well but I think Altium is still better. Linear Tech’s LTSPICE is my go-to SPICE simulation tool. My favorite website is http://www.oemstrade.com ; it enables me to search for parts at 33 different distributors with one button click. I use it to find parts or just simply validate P/N’s before I load them on an AVL.

What is the hardest/trickiest bug you have ever fixed?

Almost 5 years ago I was hired as a contract engineer to help a local medical company redesign and update their 100Watt, 900MHz, Microwave Generator. The Microwave Generator consisted of a micro controller PLL based frequency synthesizer and a RF Power Amplifier.

The 50dB Power Amplifier consisted of three RF amplification stages and was in need of a complete redesign as it was based around several now obsolete parts. My problems started in the lab after my first Power Amplifier prototypes showed up. The output stage of my amplifier was continuing to “Burst into Flames”. These made exploding Tantalum Capacitors look like child’s play in comparison. Every time the output stage blew up it would take a chunk of the Arlon PCB with it…. Embarrassingly this happened often enough with this project that I got quite good at repairing the burnt traces with copper tape, some solder and some patience. Needless to say I was stressed out, this was my first High Power RF design and I needed a “Grey Beard” to help me out. I got a hold of an older RF Engineer named John, who like most good RF engineers was a HAM Radio nut and had more electronic equipment in his basement than the Pentagon.

John and I hooked up my RF power Amplifier to a signal generator and slowly cranked up the output power until we noticed the frequency spectrum of the output started going unstable and multiple frequencies popped up. We quickly backed the power off. This was my first clue as to what I was doing wrong. Before I was never monitoring the output of the RF Amplifier with a spectrum analyzer, I was just using a RF Power meter; it was equivalent to using a multimeter to measure a voltage when you really should use a scope, so you can see more than just the “average” information. My amplifier was turning into an oscillator due to some unwanted positive feedback. A few cuts to our GND plane, isolating each stage a bit better and retuning each stages gain down a little and our Amplifier stayed an Amplifier. I am over simplifying the process we went through, but a few weeks later we had a non-oscillating RF Amplifier.

What is on your bookshelf?

The Circuit Designers Companion by Tim Williams
Texas Instruments OpAmps for Everyone Design Reference
Analog Devices Op Amp Applications reference
Home Brewing for Dummies by Marty Nachel. No my day job isn’t driving me to drink, but I believe combining hobbies is fun. I see a bunch of Arduino based Electronic Brew monitoring devices in my future.

Do you have any tricks up your sleeve?

My tricks are pretty simple. When you get in a brand new prototype always measure the continuity between ground and all the power supply rails before even thinking about hooking up power to the board. Then hook the board up to a bench supply with the current limit down as far as it will go. That way when you turn on the bench supply if your prototype is a heater you shouldn’t damage anything too bad. You need a little bit of give and take on the current limit because some designs have a bit of an inherent inrush surge current on power up and you need to make sure the bench supply can supply that before the limiting happens.

When SMT soldering always use a med to large chisel tip and plenty of no-clean flux to drag the solder across the pins. I have seen way too many people grab extremely small conical tips and expect to solder each pin individually; let the flux do the work for you.

What has been your favorite project?

A few years ago I designed a Starter Interrupt device to enable a local non-profit to sell donated cars to people with less than perfect credit. It was a neat project because I did everything from the hardware design to the embedded firmware, the PCB Layout, and wrote a Visual Studio PC application to configure the device. You can check out the complete project on my blog.

What are you currently working on?

Other than keeping busy with my day job designing various Weigh Scale related Embedded Electronics, I’ve been busy finishing up my entry for the Touchstone Semiconductor TS1001 Opamp Design contest.

What direction do you see the Electronics Industry heading in the next few years?

Companies are going to continue to “Do more with less” in terms of the number of engineers they have on staff and this isn’t necessarily because of economic reasons I strongly believe it just takes fewer engineers to bring a product to market than it did 20 years ago. This is because of all the CAD tools and integration semiconductor suppliers are now providing OEMs. For example 3 years ago if you needed an ECG front-end circuit you had to do it all discretely with instrumentation amps, op amps and an ADC. Now you can just slap down a Texas Instruments ADS1298 and get a jump start on your design. Now these integrated solutions don’t always have all the “special sauce” type features that help differentiate one OEMs product from another, but it does get you started quickly.

One of my favorite things to do when I have a bit of down time at work is to flip through the old retired engineer’s lab notebooks from the late 70’s through the 90’s. The first thing I notice is that I feel bad for the new generation of engineers reading through my lab notebooks because they are not nearly as pristine as these old ones are. The next thing I notice is how so much of their time they spent designing DC/DC converter controllers, Chopper Stabilized OpAmps, and Single/Dual Slope ADCs. These for the most part are components I can just buy from semiconductor manufacturers and I spent a lot more of my time at work solving the “How do I get Data In/Out of my Box?” type problems. But this just goes back to my point of since semiconductor manufacturers are delivering so much application specific hardware to the OEMs, we only have to focus on the “Special Sauce” instead of all the individual pieces.

I also think social media like: Twitter, Forums, Blogs, and websites like EEweb are going to become much more important in knowledge sharing and mentoring the next generation of engineers. With fewer engineers doing the same work in shorter timelines these online social media outlets can provide so much quick information to help solve the day to day problems.