If you have been using and reading about the ADALM1000 ( Analog Discovery for that matter ) for any length of time, then you have probably come across the terms like Breakout Board ( BoB ), DIP Adapter, Component Module ( CMOD ) and Peripheral Module ( PMOD ). Here, we will discuss what breakout boards are, how they can accelerate your ALM1000 prototyping and some things to look out for when you select them.
The basic concept of a breakout board is that is takes a single electrical component ( or perhaps a few) and makes it easier to connect with the ALM1000 and the rest of the project circuit. The term PMOD is specific to a range of small modules that follow the Digilent pin-out form factor. The digital connector of the ALM1000 is compatible with some of the PMODs.
Usually the component is an integrated circuit (IC). Integrated circuits have pins on them. The pins on an IC can do many things, usually an IC will have pins for the power supply, pins for providing a ground, pins for inputs and pins for outputs etc. In the past most ICs had what are called “through hole” pins which are soldered into holes drilled through the printed circuit board. This makes these kinds of devices easy to insert into solder-less breadboards. Over time the desire for smaller and more compact systems has led to the shrinking of the IC packages to the point where it was no longer possible to drill holes in the circuit board to accommodate the pins. This gave rise to what is called surface mount technology ( SMT ) or devices ( SMD ). ICs in these new packages can no longer be used directly with solder-less breadboards. A breakout board "breaks out" the pins of these SMT ICs onto a printed circuit board that has through hole sized pins that are spaced perfectly for a solder-less breadboard, making it easier to prototype and experiment with the integrated circuit.
There are many types of breakout boards - many of them are for different types of sensors, for example: temperature sensors, accelerometers, ultrasonic distance sensors, RFID tag sensors, pressure sensors, they even have seismic breakout boards for sensing vibrations from footsteps.
The market for most breakout boards is being driven because of their use with single board computers such as Arduino and Raspberry Pi. You might be wondering what the difference is between a breakout board and an Arduino Shield? Breakout boards usually have a smaller form factor where the PC board is only slightly larger than the IC. The pin-out of a breakout board is not specifically designed to fit the headers on one specific single board computer or another, it means you could use a breakout board with any micro-controller development board you want - which gives them a broader scope.
You might be wondering, if breakout boards have only one component, why not just buy the integrated circuit the breakout board uses, plug it into a solder-less breadboard yourself, and then hook them up to your ALM1000? That is great question, and there is nothing saying you can't – many people do - especially since the components by themselves are often far less expensive to buy alone from an electronics distributor like Digikey or Mouser. This of course assumes that the component in question is available in a solder-less breadboard friendly package. To make it a little simpler, the ADALP2000 analog parts kit contains a number of SMT integrated circuits already mounted onto BoBs along with many other components in DIP packages.
So why are people buying all these breakout boards?
It essentially comes down to convenience. Let’s list the ways a breakout board can help you out, and then you make the call:
Breakout boards can save you space.
We have already said that breakout boards use integrated circuits. Integrated circuits are kind of like shoes – they come in all different shapes and sizes. As was pointed out already, breakout boards utilize a tiny version of an integrated circuit called an SMD (surface mounted device). The pins on SMD parts are really small - not something you can just plug into a breadboard.
The larger form factor of an integrated circuit, called a DIP (dual inline package) has bigger pins, which fit easily into a breadboard. The DIP package of an IC will be bigger than the SMD form factor.
The point here is that breakout boards can sometimes save you space which may or may not be important for your project.
The DIP version of a component may not be available.
You may find is that the DIP version of an integrated circuit is not available. As electronic systems get smaller over time, the demand for larger components is drying up and manufactures are moving away from even offering the DIP package as an option, which ultimately brings you back to a breakout board.
Breakout Boards are designed for reuse.
Another thing about using DIP packages is that while the pins are bigger, they are not necessarily sturdy. If you plan to use a DIP component over and over, the usable life of the pins may not be very long - the connection points on a breakout board however, are heavy duty and designed for reuse.
Pin labeling on a Breakout board.
One great feature of breakout boards is that they usually have the pin names of the integrated circuit labeled on the PCB. This makes hooking up the breakout board to your project easy. Especially when there are lots of pins. Otherwise you are looking at the blank package of the IC and referencing the datasheet to try to figure out which pin is for what.
So now that you know some of the benefits of a breakout board, let's talk about a couple things you might want to consider when you are buying them.
Good documentation is like water in the desert. The more you can get your hands on the better. Let's face it - most of this electronics and programming stuff is not self-evident, you need good instructions and reference material to get it working right. A good test to use before buying a breakout board is to see what reference material can be found online for it. If nothing tangible exists - you might be spending way more time trying to get it up and running than you would prefer.
Breakout boards are not necessarily interchangeable
As you search for breakout boards, you may find that there is more than one generic version such as a “serial to parallel converter” available. If you plan on using pre-existing schematic designs for a project that references a specific version of the breakout board – i.e. maybe in the design schematic says, "use ABC breakout board", one thing you will want to check is that the breakout boards use the same integrated circuit. Also the order of the pins on the PC board might be different.
If they don't use the same integrated circuit, and you don't know how to adjust the design for these differences, then you may find that a less expensive alternate version will cost you more time in trying to figure out how to use it.
Soldering may be required.
Many breakout boards are sold as kits. Usually the only things you have to solder are the header pins that allow the breakout board to plug into the breadboard - this can be easy to do. It could also be the case that the manufacturer just sells the breakout board with the SMD component mounted on the board and you have to buy the pin headers separately.
Sometimes you can’t find a breakout board with the specific IC you are looking for. Some manufacturers supply generic SMD to DIP adapter boards for a range of different SMT packages. Buying one of these adapter boards and the IC separately can solve your problem but will require you to be able to solder the SMD IC to the board. This can require special tools and may be very difficult to do with just a soldering iron.
So those are a few things to keep in mind when selecting breakout boards.
Using the correct supply voltage.
Finally, once you actually have your breakout board, make sure that you know what supply voltage it needs to be hooked up to.
The ALM1000 has three “supply” voltage pins, +2.5 volts, +3.3 volts and +5 volts. Many breakout boards use a supply voltage of 3.3 volts. Sometimes the supply voltage will be printed right on the PCB by the associated pin, but other times it will just have Vcc, so you will want to check the specs on the breakout board and the IC before applying power to the circuit.