Category Archives: Medical Industry

Everything You Need to Know About the SMA Connector

SMA Connector for RF Signals

The SMA connector is an incredible workhorse, offering a wide variety of applications from which it can provide the perfect solution. Because of its versatility, the SMA connector is used in every industry from telecommunications to medical. In today’s spotlight series, we’ll hone in on the venerable SMA RF connector, which provides a critical function in today’s cutting edge medical devices.

What is an SMA connector?

First off, SMA stands for sub-miniature type A. Subminiature connectors are small, hence the name, and are useful in high-frequency applications. This is because SMA connectors are able to provide a steady broadband connection from the KHz range on up to 18 GHz. The inherent reliability of the SMA connector is achieved from a constant impedance of 50 ohms and also because of its low reflection. Electrical impedance is simply a measure used to find the level of opposition that gets applied to a current inside a circuit when the voltage gets applied to it. 50 ohms is considered a good middle ground in the realm of standard characteristic impedance. 

SMA connectors can achieve low reflection and good attenuation because of their shape, which helps to maintain a uniform connection contact. The SMA is coaxial, with the characteristic screw-type coupler; however, these should not be confused with standard coaxial hooking up a home’s cable or internet. To hook up an SMA to a coax requires a special adapter. 

Standard SMA Connector Specs Snapshot:

  • Utilizes a one-quarter inch and 36 thread type coupler
  • Male SMA connectors use a five-sixteenths inch hex nut. This allows the application of torque by a standard one-half inch wrench. The applied torque can be used to easily tighten or loosen the connector.
  • Female SMA connectors utilize a thread for coupling that is 4.32 millimeters long.
  • Employs a special silicon rubber O-ring. This helps to provide separation between the body and the coupler which in turn creates a barrier to outside environmental factors like dust.

Even within a specialized connector like the SMA, there are several different types. Next up, we’ll focus on a Meridian specialty, the SMA RF connector, which provides the crucial connection many different devices in the medical industry rely on to run effectively.

How SMA RF Connectors Help Medical Breakthroughs Happen

RF stands for radio frequency and applies to a range of coaxial electrical connectors. The SMA is one of the most used of the RF-type connectors. Because of the screw-type coupler, the SMA is sturdy mechanically and offers durable performance throughout the life of the system – really important considerations for life-saving medical devices. 

SMA RF connectors come in a male and female variety to provide the crucial connections high frequency medical devices need to consistently send and receive power and data. Male SMA connectors are easily recognizable because they resemble a standard coaxial connection with a center pin inside of its threaded barrel. The female connector acts more like a sleeve which helps provide a good, sturdy connection between the types. Female connectors are usually affixed to a stable device and the male is then used in a removable wire connection for the greatest flexibility within the electrical system.

The sturdiness of construction, extremely reliable performance, and how it fits perfectly into the electrical system is what makes the SMA RF connector the go-to for fields with complex requirements like the medical industry. We produce tens of thousands of SMA RF connectors for medical devices each year. Designing and producing each to exacting standards, we are able to power the devices medical staff rely on to diagnose and treat patients every day. 

Designing the Perfect SMA RF Connector

SMA RF connectors can range from a single connector, customized to provide the perfect connection in an existing system, to a custom cable assembly that provides multiple SMA connections and adapters for providing the greatest range of application. Many SMA RF connectors available today utilize a right angle design but there are also straight angle designs available, all depending on the circuit. Right angle design is a popular choice because it helps maintain the impedance we discussed earlier at a standard level. 

Meridian’s gifted engineering and design team has to calculate the dimensions and structural components of the connection to incredible preciseness. Further, our production team must be absolutely flawless in their assembly, with special attention to the soldering. Too much soldering can lead to what’s known as an impedance mismatch. Impedance mismatch can also occur when the dimensions aren’t exactly right, a mechanical failure, or even when too much air surrounds the contact within the connection. 

Imagine if any of these were to occur during a risky surgery, where hospital staff is dependent upon the many medical devices around them utilizing SMA RF connectors. 

Different Ways to Mount SMA Connectors

  • Panel Mount: this is a female mount made for tough conditions like in the military and industrial settings. With a two-hole or four-hole configuration, panel mounts are easily applied to instrumentation and wireless infrastructure.
  • Bulkhead Mount: female mount with a thread length that is usually longer than the typical 4.3 millimeters to more easily attach to a wall or panel using a nut and washer.
  • Through-Hole Mount: can be vertical or 90 degrees and comes in non-magnetic varieties that are used often in the medical field.
  • Edge Mount: vertical mount that comes in both a standard and drop in variety. 

Losing signal or power mid-procedure isn’t an option which is why our clients have come to know they can depend on Meridian for a quality product that is designed to function as intended cycle-after-cycle.

Does UL-certification matter with SMA RF Connectors?

Creating a product for a device that literally can mean life and death for a patient is a matter no custom cable manufacturer should ever take lightly. We’ve already seen where small deficiencies in the connection can lead to catastrophic failure. This is one of the many reasons we utilize UL-certified components in all of our products, including the SMA RF connector. 

UL-certified components have been tested and verified for their structural integrity, durability, and overall functionality. This allows our design team to utilize components that have known and very specific operating ranges. In this way, we can piece together the perfect amalgamation for even the most complex custom cable assembly

Meridian is proud to utilize UL-certified components and to maintain status as a UL-approved manufacturing facility, having met the stringent quality assurance and quality control (QAQC) requirements of Underwriters Laboratories (UL). We also are proud to have had and continue to maintain our certification as ISO 9001:2015. This difficult to achieve certification requires demonstrable and exceedingly high QA/QC programs that focus not just on quality of the product, but of the entire process – which includes cradle to grave design, sourcing, prototyping, mass assembly, testing, but also emphasizes customer service/satisfaction. 

Making an SMA RF Connector That Performs Flawlessly in its Application

Impedance matching is a crucial step with custom SMA connectors. The design and test teams of Meridian rely on decades of experience in custom cable manufacturing to select the perfect SMA connector to do the job, in the environment, and in conjunction with the other elements of the system – especially terminations. These different components all must work in perfect harmony for the electrical system to perform as it should. 

To produce a one-of-a-kind solution that works perfectly in its intended environment, we are fanatical in our approach to quality. As discussed, quality starts with the very first client contact, through every step of the design and manufacturing process, and then beyond with an industry-leading product warranty. We test each and every product that rolls off our assembly line so that our clients know the product they receive will perform under their exact specifications. 

How do you test SMA RF connectors?

It is indeed rare to go from design straight to volume production without many periods of testing and prototyping in between. Prototyping allows our design team to test several different configurations of the same SMA RF connectors in harsh real world conditions. Often these are even tougher than the actual circumstances the system will face every day. We call this our “advanced life testing lab” which subjects the components to all manner of freezing temps, scorching heat, salt, and other environmental factors that need to be mitigated against during the design phase. 

Aiming for as close to perfection as humanly possible, we also employ highly accurate, automated Cirrus testers. However, there are times such as when the product is entirely unique, that we must design a correspondingly unique and entirely-custom testing unit to ensure the component’s functionality, structural integrity, and above all, safety. 

How to Get a Custom SMA RF Connector Project Started

When you need the perfect solution for a medical device requiring a SMA RF connector, our team is readily available to complete the project on-time and on-budget. Our design managers work with you to understand all of the complexities surrounding your project, set production milestones, lock out the appropriate tools from our massive tool crib, and manage the entire process to ensure the product is made to your absolute satisfaction. Contact us today to go over your specs and outline your options with our dedicated sales team.

4 Uses for Custom Cable Assemblies in Healthcare

Off-the-shelf cable wiring is acceptable for many applications like power tools or home wiring. However, when dealing with sensitive equipment and peoples’ lives, it’s worth paying a little more attention to how you invest in custom cable assemblies.
custom-cable-assemblies

Durability

Medical devices are subject to intense strain on a daily basis, from heavy-use by devices such as defibrillators to low-intensity, but high exposure, devices such as pace-makers. The amount of regular stress that these devices must endure and overcome is immense.

Disposability

There is some imbalance in viewpoints when it comes to cable wire disposability vs. reusability. Reusable wires must be able to endure the sterilization process and remain functional, while disposable wires can be less durable but must be replaced after single-use. For these purposes, it really comes down to use of the cable wiring. In some situations safety trumps cost and disposability is preferred, whilst other times reusable devices are preferred because the machines are too expensive to replace.

Biochemical Interface

One of the most taxing conditions for wiring operation is at the biological technological point of contact. Customized cable assemblies may need to comply with specific regulations and pass a series of stress tests. Working with an experience cable manufacturing company like, Meridian Cable Assemblies, will ensure wiring will meet strict standards and comply to federal regulations.

Adaptability

Devices must be able to adapt and perform during many different scenarios. Custom cable assemblies allow you to design assemblies and wire harnesses equipped with the perfect technical specifications to meet their needs for each situation.

Cable Assemblies for Healthcare

For more than 25 years, Meridian Cable Assemblies has been designing and manufacturing cable assemblies for device manufacturers. We design more than 70 percent of the products we produce and work directly with our clients to ensure the highest quality. Custom cable assemblies are the best way to get the perfect device ready for both medical professionals and their patients.

What You Need to Know About Electric Cable Assemblies

What You Need to Know About Electric Cable Assemblies

Electronic Cable Assemblies

Electric cable assemblies are found on medical products, military equipment, industrial controls and machinery, and all kinds of consumer electronics. Electric cables can be defined as cables that transmit control signals or information, or that supply low current power typically below 5 amps. Often the power is DC by sometimes it can be AC, but in either case for electronic cable assemblies the power is low.

Electric cable assemblies are used on a wide variety of equipment they often experience wide ranges of movement, or flexing. Regardless of how much movement the assembly experiences it is critical that it be designed correctly to withstand any flexing. This is important for two reasons. One, a failed cable assembly means the data or power stops and this can have bad consequences. Two, a wrong design can increase costs beyond what the application truly needs.

Some applications require a lot of flexural capability. Examples are medical cables, military cables or industrial control cables where failure is not an option or the equipment runs quickly for long periods of time. Other applications don’t flex much at all. Examples are vending machine cables, security cables or box build wire harnesses that are installed one time and never move again.

Flexural requirements for wire assemblies can range from 1, in the case of wire harnesses, to hundreds of thousand for industrial cables. Some products need hi-flex cables to ensure they never fail, which is the case for medical cable assemblies and military cable assemblies.

How many flexes a cable can withstand is a direct function of the materials used in construction and the process employed to make the product.

In regards to electronic cable assemblies, there are really only 3 types of materials in any cable or wire, metal, plastic and fillers.

  • Typically the metal used is copper in some fashion. The copper can be bare, plated with another metal such as tin, or in some cases clad around another metal such as silver.
  • The plastic can be any combination of polyvinyl chloride, PVC, polyethylene, PE, polyurethane, PU, or thermoplastic elastomer, TPE.
  • Fillers are used to ensure the cable’s cross section is uniform in shape, whether round, oval or square a uniform cross section is critical.

At the heart of all cables and wires is metal, typically copper. Metal as we all know comes in many varieties and copper, for most applications, has the best attributes to make a cable or wire. As we also know most metals don’t like bending. This is especially true of larger pieces, which is why most electronic cable assemblies use stranded wires. This means to make a certain gauge conductor many smaller strands of copper are used. The amount of copper doesn’t change it is just spread across many conductors. As we all know small things bend easier than large things so a wire or cable made with a high strand count will have a long flex life than a wire or cable made with one conductor.

Around the conductors is most often plastic of some kind. We all experience and use plastic every day and the variety is quite amazing. From the rigid bodies of cell phones, to the semi flexible sides of a milk or water container, to soft pliability of a rubber band plastics used in custom cable assemblies come in even more varieties than copper. Some custom wire assemblies can accept very rigid constructions, but for custom electronic cable assemblies usually a high degree of flexing is required. For these applications it is best to use plastics capable of handling repeated bending. These can range from PVC all the way to PTFE.

Obviously with all these factors designing a custom electronic cable can range from simple to very complex, so finding a qualified cable and wire vendor is critical for many companies. Meridian Cable recently designed, manufactured and cycled a cable assembly to over 200,000 cycles without any failures. If you need custom electronic cable assemblies, Meridian Cable can design and manufacture just what you need. Contact us today for any custom cables needs or view some of our cable assembly designs.

3 Reasons Why Coil Cords are Important in a Wireless World

3 Reasons Why Coil Cords are Important in a Wireless World

28-gauge 30-gauge coil cords

Coil cords are everywhere, from the back of a semi truck, to a camera’s flash strobe to the arcade games where you manipulate a claw to pick up a toy. Coil cords are used in a wide variety of industries too. Coiled cables are used by the medical industry, security industry and industrial control industry to name but a few. And in this age of everything wireless a good question is why would anyone use a coiled cord? So no matter what you call it, a coil cord, curly cord or coiled cable this article will give some reasons why a coil cord is still the right solution for many applications.

1) There are three main reasons to use a custom coil cord instead of wired solution. The first is power. While wireless solutions exist for many application when electrical power needs to be supplied it almost always is done with wire or cable. When something is wireless it means the product uses radio waves of some sort. Radios that we listen to are one example of just such a product. We could connect all radios with coil cords and send the signal along the cord, but that isn’t practical for long lengths of distances, so radio waves are used to send the signal. When radios waves are sent they move in all directions and don’t really care what they hit, and don’t react with anything but antennas “tuned” to their frequency.

Power is different. If power was transmitted like radios wave it would interact with anything metallic in its path. And if the metallic object was connected to something the power would transfer from the metal to the object. This would act as conductors, and could be very bad as in the extreme case of lightning, which is a very powerful wave of energy. So cables, and coil cords, are used as a part to transfer power for obvious safety reasons.

2) The second reason coiled cables are used instead of wireless is to avoid electronic noise. We live in a world filled with radio waves all around us. Often custom coil cords are used instead of radio waves because the items needing the signal would be damaged or impaired by other signals. A classic representation of this is again a radio, only the old AM kind. We have heard static and other stations fade in and out on radios. The static we hear is noise. If a coiled cord was used instead of radio waves, and the radio was shielded from outside waves, we wouldn’t hear static. However connecting all radios with coil cords is impractical, but in an operating room it isn’t. This is why cables and coil cords are often used in hospitals.

3) The third reason to use a coil cord instead of wireless signal is security. In the early days of cell phones, it wasn’t unusual to be talking with someone one moment and the next be speaking with someone else. This was because the cellular phone systems and their suppliers at that time were not as advanced as now. For most people this is not an issue, but if you are in the military it can be a matter of life or death. Having a coiled cable transmit signal or power ensures there will be no interruptions. Imagine a surgeon in the operation room losing power at a critical point in surgery. This is why where failure is not an option coiled cords are often used.

Wireless products are great, and they have made our lives much more mobile and easy. However as the above points show custom coil cords and cables are still very necessary. If you need power, a clean signal or security of transmission a coiled cable is a great solution. Meridian Cable manufactures and designs coil cords for any coiled cable need you have.

Coil Cords – Physical Shape and Performance

Recently Meridian Cable was approached by a medical device company to solve a “spring” problem.  The medical company’s device weighs about 1 pound and will be connected to a patient via a coiled cord.  The medical company wanted the device to stay put when the cable was extended 5 inches, however they didn’t want the 1 pound mass of their device to pull on the patient if the device fell off a standard bedside height surface.  This meant the device had to almost free fall for 22 inches.

The customer also had physical requirements for the coil diameter and overall cable length.  The coil diameter could not exceed 0.60 inches in outside diameter and the overall cable length must be no longer than 42 inches.  The coiled diameter could be smaller and the retracted length, or coiled section, could be adjusted.

To solve this problem the following force parameters were established.  At 5 inches extended the force must be less than 0.25 pounds and at 22 inches extended the force must be between 1.0 and 1.25 pounds.  The 5 inch force was designated “B” and the 22 inch force was designated “C”.

Several cable constructions were made, but all of them had 6, 24 awg conductors.  We settled on two cable designs with the primary difference being the type of shielding used.  Testing was performed over several days using various configurations and the results were achieved.

SAMPLE # CABLE # RETRACTED
LENGTH
(inches)
ROD
OD
(mm)
COIL
OD
(inches)
“B”
FORCE
(pounds)
“C”
FORCE
(pounds)
1 3 6.25 5 0.55 0.55 2.20
2 3 6.25 6 0.57 0.53 1.43
3 3 6.25 8 0.68 0.13 0.66
4 3 5.5 4 0.54 0.59 2.50
5 4 6.38 5 0.55 0.44 1.60
6 4 6.75 6 0.57 0.42 1.30
7 4 6.75 8 0.68 0.08 0.62
8 4 6 4 0.54 0.88 2.70
9 3 6.25 7 0.61 0.26 1.01
10 3 10.25 6 0.57 0.13 0.77
11 3 4.25 8 0.68 0.31 1.10
12 4 6.38 7 0.61 0.29 1.01
13 4 10.5 6 0.57 0.18 0.77
14 4 4.38 8 0.68 0.24 1.03

Based on the above data specific samples were made for the customer to test.  See a video of the coil cord manufacturing process or view some of our coil cord designs.