The Right Adapters and Kits Enable Flexible, Efficient Breadboarding with Modern Components

By Bill Schweber

Contributed By Digi-Key's North American Editors

Thanks to the widespread use of tiny passive and active devices and circuit operating frequencies well into the gigahertz (GHz) range, creating and evaluating a circuit design prior to committing to pc board, and then advancing on to a near-final prototype, is an increasingly difficult and often frustrating challenge. The breadboard kits and techniques which worked for leaded devices and dual in-line package (DIP) ICs are not compatible with today’s high-density IC packages, lead pads under the package, and nearly invisible surface mount technology (SMT) devices, as well as complete RF or processor modules.

However, there is good news in the form of bench-based development tools which allow basic breadboards to be created, while meshing with separate subcircuit modules. Using these breadboard systems, hobbyists, makers, do-it-yourself (DIY) enthusiasts, and engineering professionals can build, test, and integrate subsections of the overall product into a complete and functional unit.

This article examines the basic issues associated with breadboarding the modern electronics component. It then looks at how adapters and breadboard kits from vendors such as Aries Electronics, Schmartboard, Inc., Adafruit Industries LLC, Global Specialties, and Phase Dock, Inc. can be used as the basis for prototypes that more closely resemble the final product.

Finally, it shows how these ease the construction of useful, reliable breadboards which can validate circuit topologies and interfaces, allow for connection to independent modules and evaluation boards as needed, and lead to meaningful prototypes.

Where did the electronics breadboard come from?

The use of the term “breadboard” for a circuit that looks rough and even crude may seem mystifying, but the derivation is clear and well documented. In the early days of electronics, with self-powered crystal radios and even basic vacuum tube radios, DIY experimenters and makers (before that word was in use with today’s context) would build circuits on an actual breadboard, the wooden board used for cutting bread. They used tacks or nails as the connection points and wrapped the wires around them, sometimes even soldering these connections (Figure 1).

Image of using a wooden cutting board as the base for DIY electronic circuitsFigure 1: The term “breadboard” derives from the use of a wooden cutting board as the base for DIY electronic circuits such as this three-tube radio. (Image source: Warren Young/ Tangentsoft.net)

Of course, these wooden breadboards are obsolete as platforms for circuits using modern components. Despite this, the terms “breadboard” and “breadboarding” have become standard terms associated with roughly built demonstration circuits or subcircuits. However, the advance of electronic technology from vacuum tubes to discrete leaded transistors and passive components, DIP ICs, and now to almost-invisible surface mount devices, has had significant impact on breadboarding techniques and platforms.

What’s the difference between a breadboard and a prototype

An obvious question concerns the difference between a breadboard and a prototype. There is no formal demarcation between the two, and the terms are sometimes used interchangeably. However, most engineers use the term breadboard to signify a rough layout of a circuit or subcircuit which needs to support preliminary design phases including:

  • Checking the viability of a basic circuit idea, function, or design approach.
  • Developing and verifying software drivers.
  • Ensuring compatibility of interfaces between subcircuits or between a circuit and transducer or load.
  • Working out data-link protocols and formats.
  • Developing and verifying a presumed model.
  • Evaluating circuit and functional performance.

From the above list, it’s easy to see the many important roles the breadboard plays in product design even though it is not a complete system and it lacks the packaging as well as many of the “bells and whistles” of the final product. For example, a breadboard often relies on an external power supply rather than the internal supply of the shipped product. Due to its broad and open layout, the breadboard is usually amenable to probing, adjustment, and even replacing components. However, the physical realities of such a spread-out layout means that some of the performance capabilities are unavailable, especially those associated with higher frequency operation, due to layout and component parasitics and interactions.

In contrast, a prototype is much closer to the final product and uses the same components, packaging, form factor, and user I/O. In addition to being functionally complete, a prototype is often used to check manufacturing concerns such as physical clearance and assembly issues, thermal paths, user interaction, and visual appeal and appearance.

Start with basic adapters

Today’s breadboarding requires the ability to connect to and use the tiny ICs that dominate modern designs. For example, it is possible to solder a six-lead SOT-23 IC to a larger pc board, but making—and especially changing—connections to the device will be difficult due to its small size and narrow lead pitch. The situation is more challenging when the IC only has underbody bump pads.

One solution is to use a device such as Aries Electronics’ LCQT-SOT23-6 socket adapter. This transforms a SOT-23 to a six-lead DIP housing (Figure 2). Once the SOT-23 device looks like a DIP with 0.1 inch (in.) lead spacing, it can be used with one of the breadboarding solutions designed for larger DIP devices.

Image of Aries Electronics LCQT-SOT23-6 socket adapterFigure 2: The LCQT-SOT23-6 socket adapter transforms a tiny, hard-to-handle six-lead SOT-23 package into a much more manageable DIP device with standard DIP lead spacing. (Image source: Aries Electronics)

Many designs use an array of SMT components with different package sizes and pin configurations. For these situations, multiple single-IC socket adapters may become unwieldy to handle and interconnect. Schmartboard’s 202-0042-01 QFN adapter board can minimize the potential confusion (Figure 3). This 2 × 2 in. board accepts up to five different ICs having 16 and 28 pins with 0.5 millimeter (mm) pitch, 20 pins with a 0.65 mm pitch, and 12 and 16 pins with a 0.8 mm pitch (for QFN devices).

Image of adapter board such as the Schmartboard 202-0042-01-QFNFigure 3: An adapter board such as the 202-0042-01-QFN accommodates on-board soldering and connection breakout for multiple SMT IC packages. (Image source: Schmartboard)

The 202-0042-01-QFN uses patented technology to enable fast, easy, problem-free manual soldering of these tiny surface mount components. In addition, the multiple plated through holes associated with each IC pin make it easy to connect the resident components to each other, if desired, or to other devices and boards.

Sometimes the breadboarding challenge is not in connecting to an IC but instead accessing and monitoring pins of a cable or peripheral-device connector. For example, when the 25-pin RS-232 connector was the dominant communications interface, a “breakout box” with on/off switches and jumper terminals for most of the pins was as common as a multimeter (Figure 4).

Image of RS-232 breakout boxFigure 4: This RS-232 breakout box is essential for monitoring and re-arranging the wires in the 25-pin cable of that formerly very widely used connector and standard. (Image source: Wikipedia)

While these RS-232 boxes are rarely needed now, there’s an analogous need for breakout functionality for peripheral devices such as Micro SD cards. A useful adapter for this function is the Adafruit Industries 254 Micro SD Card Breakout Board which enables designers to connect to, test, and verify both the hardware interface connections and driver software for these widely used memory cards (Figure 5).

Image of Adafruit 254 Micro SD Card Breakout BoardFigure 5: Using the Adafruit 254 Micro SD Card Breakout Board, designers can easily interface with, access, and monitor signals between a system processor and this peripheral memory device. (Image source: Adafruit)

The board includes an ultra-low dropout regulator to convert voltages between 3.3 volts and 6 volts down to 3.3 volts for the Micro SD Card, and a level shifter to convert the interface logic (3.3 volts to 5 volts) to 3.3 volts so the board can connect with 3.3 volt or 5-volt microcontrollers. The separate header can be soldered into the adapter to bring the connections out to pins spaced with a 0.1 inch pitch.

Moving beyond adapters

Adapters can solve issues with connecting to individual components, but these are only the building blocks of the final design. The now accessible components need to connect to other active and passive components, support input/output (I/O) interfaces, enable component replacement, and provide for formal test points and even unanticipated probing.

One of the first breadboards to easily and directly accommodate devices in dual in-line packages (DIP), as well as discrete leaded components was the solderless breadboard, developed in the 1960s and still in wide use. It’s convenient, accessible, easy to use, and supports a reasonable component density.

An example is the PB-104M externally powered solderless breadboard assembly from Global Specialties, which is well-suited for prototyping of low-frequency circuits (Figure 6). It is mounted in a 21 × 24 centimeter (cm) frame (9.45 in. × 8.27 in.) and includes 3220 tie points, four binding posts for connecting power supplies, and supports 28 16-pin ICs; jumpers are made using 0.4 mm to 0.7 mm diameter wire stripped at the end. The key to the versatility of this breadboard is that the holes are spaced 0.1 in. apart to accommodate standard DIP components as well as the pins of adapters and headers, in addition to wire leads.

Image of PB-104M solderless breadboard assembly from Global SpecialtiesFigure 6: The PB-104M solderless breadboard assembly from Global Specialties accommodates multiple DIP ICs, DIP-footprint adapters, discrete components with wire leads, and individual wire jumpers. (Image source: Global Specialties)

In use, the solderless breadboard is a connectable platform where DIP ICs and other components are connected using short pieces of solid wire inserted into the holes, which also connect to the component leads. The two outer rails along each side are usually reserved for power and ground, and they supply the active components via short feeder wires (Figure 7).

Image of Analog Devices solderless breadboardFigure 7: In a solderless breadboard, the two outer rails along each side are usually reserved for power and ground. Short feeder wires connect the rails to the active components. (Image source: Analog Devices)

It’s important to maintain some discipline when using a solderless breadboard. For example, it’s a good idea to use color-coding to help identify the wires, such as red for a positive rail, black for a negative rail, and green for ground. Also, users need to take care to lay the jumper wires flat on the board to minimize clutter, and route interconnect jumpers around the ICs rather than over them so the ICs can be probed and even changed with minimum disruption. Otherwise, the solderless breadboard—like so many other “temporary” implementations—can become a “rat’s nest” and be very difficult to debug or trace (Figure 8).

Image of care and discipline are needed when installing the jumpersFigure 8: Care and discipline are needed when installing the jumpers for anything but the smallest project in a solderless breadboard; otherwise, a maze of indecipherable wires is the result. (Image source: Wikipedia)

A breadboard mix for today’s designs

The solderless breadboard is still widely used due to its convenience, flexibility, and versatility, but has severe limitations with modern designs which operate at high clock rates and frequencies, often combining pre-assembled computer boards, RF circuits, and modules, and power modules. In order to accommodate these, a system is needed that enables integration of multiple breadboards, prototype platforms, and subassemblies into a larger unit that can then support the completed system functionality.

Once such breadboard is the Phase Dock 10104 mounting prototyping system (Figure 9). A core system consists of a 10 × 7 in. base matrix with 54 square inches of work surface, five “Clicks” in two sizes used to mount electronics, as well as “Slides” used to mount Arduino, Raspberry Pi, or similar modules; it also includes the small hardware items such as screws which enable the engineer to assemble the Click/Slide combos, mount electronics on the Slides, mount electronics directly to the Clicks (without Slides), add higher profile “tower” electronics, and manage wires and cables. There’s also an optional clear plastic cover that provides protection, enhances appearance, and facilitates transport.

Image of Phase Dock 10104 Mounting Prototyping SystemFigure 9: The basic Phase Dock 10104 Mounting Prototyping System includes a Base Matrix (top); Clicks for mounting electronics (middle row); Slides for using Arduino and similar platforms (bottom row); and the all-important mounting hardware (bottom row - left). (Image source: Phase Dock, Inc.)

This product development system allows for the mixing, on a single platform, of different breadboard and module technologies, such as solderless breadboards, specialty boards with screw terminals and connectors, processor platforms such as SparkFun’s RedBoards, and even brackets holding discrete switches and potentiometers (Figure 10). They are all mounted firmly to the Phase Dock base and then connected as needed to test the system concept and debug it with needed access to key signals and test points.

Image of Phase Dock system supports “mix and match” mountingFigure 10: The Phase Dock system supports “mix and match” mounting and interconnection of system elements including solderless breadboards (in white), specialty pc boards (green), and processor platforms such as SparkFun’s Redboards (red) for this automated controller system. (Image source: Phase Dock, Inc.)

Vendor evaluation boards engage breadboards

High-performance ICs—especially those used for low-level signals, precision amplification, or RF signal processing—almost inevitably are now offered with evaluation boards or kits. This is necessary since setting up such advanced components to check their performance in the target application and integrating them with the rest of the system requires use of appropriate support components (mostly passives), plus careful layout and connections. The issue for the designers is how best to work with these evaluation boards, as their utility with respect to the final system design ranges from very useful to a hindrance.

Consider an evaluation board designed to fully exercise a component. As such, it includes additional support components such as memory, local DC-DC regulators, and perhaps even a microcontroller. While these components may be needed for a standalone evaluation, they may also interfere with actual use of the subject IC in the engineer’s product design.

At the other end, many of these evaluation boards have components such as the necessary specialty connector. Using the evaluation board relieves the designer of having to redo that circuity (“reinvent the wheel”); a well-done and properly documented evaluation board design is usually as good or better than a circuit created by someone at the vendor who may be intimately familiar with the IC.

The designer’s challenge, therefore, is to recognize and leverage the benefits of the vendor-supplied evaluation board in the breadboarding arrangement. Consider a “small” IC such as Analog Devices ADL6012, a 2 GHz to 67 GHz, 500 megahertz (MHz) bandwidth broadband envelope detector. The basic interconnection of this 10-lead LFCSP looks fairly simple on its schematic diagram, but actual use is more difficult as it requires a careful layout, bypassing, and high-end RF connectors (Figure 11).

Diagram of Analog Devices ADL6012 broadband envelope detectorFigure 11: Connecting and using the Analog Devices ADL6012 broadband envelope detector looks simple enough “on paper”, but, there are many design and layout subtleties. (Image source: Analog Devices)

For designers looking to incorporate this RF IC into their design, it makes sense to first understand its characteristics, test its interfaces, and “fine-tune” its fit in the overall project by leveraging the ADL6012-EVALZ evaluation board at the breadboard stage, prior to creating a final schematic and working out the layout and packaging (Figure 12).

Image of Analog Devices ADL6012-EVALZ evaluation boardFigure 12: The ADL6012-EVALZ evaluation board relieves the designer of dealing with the many subtle intricacies of designing in this simple-looking, yet sophisticated IC; incorporating it into a breadboard minimizes product development time and frustration. (Image source: Analog Devices)

The breadboard challenge is to physically enable use of the evaluation board, add power supplies, and provide the RF input amplifier and specified differential output load, along with any processor and interfaces for the pre-prototype phase leading to the prototype product configuration. Doing so will require a combination of breadboarding techniques, platforms, and approaches.

Conclusion

Adapters and breakout boards enable designers to integrate, interconnect, exercise, and evaluate the tiny, often leadless components which are standard in nearly all modern products. Newer iterations go beyond the still widely used solderless breadboard and enable mixing and matching of components, modules, and other assemblies. These enhance physical ruggedness, minimize unsightly, error-prone, and unreliable mounting and wiring. Using these adapters and breadboards accelerates the test and debug phase and leads to viable prototypes in less time.

Disclaimer: The opinions, beliefs, and viewpoints expressed by the various authors and/or forum participants on this website do not necessarily reflect the opinions, beliefs, and viewpoints of Digi-Key Electronics or official policies of Digi-Key Electronics.

About this author

Bill Schweber

Bill Schweber is an electronics engineer who has written three textbooks on electronic communications systems, as well as hundreds of technical articles, opinion columns, and product features. In past roles, he worked as a technical web-site manager for multiple topic-specific sites for EE Times, as well as both the Executive Editor and Analog Editor at EDN.

At Analog Devices, Inc. (a leading vendor of analog and mixed-signal ICs), Bill was in marketing communications (public relations); as a result, he has been on both sides of the technical PR function, presenting company products, stories, and messages to the media and also as the recipient of these.

Prior to the MarCom role at Analog, Bill was associate editor of their respected technical journal, and also worked in their product marketing and applications engineering groups. Before those roles, Bill was at Instron Corp., doing hands-on analog- and power-circuit design and systems integration for materials-testing machine controls.

He has an MSEE (Univ. of Mass) and BSEE (Columbia Univ.), is a Registered Professional Engineer, and holds an Advanced Class amateur radio license. Bill has also planned, written, and presented on-line courses on a variety of engineering topics, including MOSFET basics, ADC selection, and driving LEDs.

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Digi-Key's North American Editors