Switching a signal is easy when no voltage or current is present.
Hot switching is different.
When a switch opens or closes while electrical energy is present, the contacts can experience arcing, localized heating, material transfer, and erosion. Over enough cycles, these effects can increase contact resistance, degrade repeatability, or cause the switch to fail altogether.
For applications such as automated test equipment, semiconductor test, instrumentation, protection, and other high-reliability systems, hot-switching capability is therefore not simply another line on a datasheet. It can determine the usable lifetime of the switching system.
Cenfire designed its MEMS switching technology specifically to address this problem.
Hot Switching Is One of the Hardest Problems in Electromechanical Switching
A mechanical contact does not transition instantaneously between open and closed states.
During a hot-switching event, electrical energy can be concentrated into an extremely small region of the contact as the switch makes or breaks connection. Depending on the circuit, stored energy from capacitance and inductance can contribute to the electrical stress experienced by the contact.
The result can include:
- Electrical arcing
- Contact erosion
- Localized melting
- Material transfer
- Increased contact resistance
- Contact welding
- Reduced electrical endurance
The challenge becomes even greater as switches become smaller.
MEMS switches offer enormous advantages in size, speed, integration, and parasitics, but shrinking the contact structure also means the contact metallurgy and mechanical design must survive electrical events occurring across microscopic areas.
That is where Cenfire has focused significant engineering effort.
Cenfire Engineered the Contact for Electrical Endurance
The Cenfire switch is not simply a mechanical relay reduced to MEMS dimensions.
Its contact structure, materials, actuation system, and operating mechanics were developed together to improve electrical endurance under real switching conditions.
Cenfire has performed extensive hot-switching characterization by repeatedly switching devices under electrical load and examining how the contact evolves over time.
Under scanning electron microscopy, individual electrical events can be observed as microscopic features on the contact surface. A contact may show evidence of hundreds of thousands of switching events and continue operating.
That is important because it demonstrates something more meaningful than theoretical lifetime.
It demonstrates that the contact can tolerate repeated electrical stress without immediately welding or catastrophically failing.
Cenfire’s hot-switching development has demonstrated more than two orders of magnitude improvement in electrical endurance compared with earlier MEMS relay technology evaluated under comparable conditions.
We Test the Worst-Case Condition
Not every switching application creates the same contact stress.
AC and RF signals naturally pass through zero voltage or zero current conditions during each cycle. Depending on switching timing and circuit conditions, those zero crossings can substantially reduce the energy experienced by the contact.
DC switching does not provide that natural zero crossing.
That makes DC hot switching an especially demanding test of contact reliability.
Cenfire has intentionally focused its development on these difficult conditions.
We have addressed the worst-case scenario to provide confidence to engineers for the most demanding test conditions.
If the switch can survive repeated hot-switching events under challenging DC conditions, engineers can have greater confidence when applying the technology across a much broader range of signal environments.
Hot-Switching Reliability Without Giving Up MEMS Performance
Electrical endurance by itself is not enough.
A switching technology used in modern test and instrumentation systems must also preserve the electrical characteristics of the measurement path.
The Cenfire CF2140 combines hot-switching capability with:
Less than 10 µs switching time
Fast switching can reduce test time and enable rapidly reconfigurable measurement architectures.
Less than 1 nA leakage at 50 V
Low off-state leakage helps protect sensitive DC and parametric measurements.
Approximately 0.2 pF typical open capacitance
Low capacitance reduces loading of high-frequency signal paths and improves isolation.
DC to 6 GHz signal routing
A single switching platform can support DC, low-frequency, and RF signal paths.
True galvanic isolation
Unlike semiconductor switches, an open Cenfire contact creates a physical air gap rather than maintaining a semiconductor conduction path between the two sides of the switch.
Together, these characteristics allow engineers to gain the electrical advantages traditionally associated with mechanical relays while achieving the size and switching speed expected from MEMS technology.
Why This Matters in Automated Test
Hot switching is particularly important in automated test equipment because switching devices may operate continuously for years.
Every additional switching operation matters.
A relay that performs adequately for thousands of cycles may become the dominant maintenance item when a production test system executes millions of switching operations.
Poor electrical endurance can result in:
- Increasing contact resistance
- Measurement drift
- Intermittent failures
- Relay replacement
- Board replacement
- System downtime
- Additional calibration and maintenance
- Lost production capacity
Improving the endurance of the switch therefore affects considerably more than the cost of the switching component itself.
It can improve the total cost of ownership of the entire test system.
For load boards, device interface boards, probe cards, PXI systems, LXI instruments, benchtop equipment, and semiconductor ATE, that reliability advantage becomes increasingly valuable as switching density and parallel test increase.
Mechanical Isolation. Semiconductor-Class Integration.
Historically, engineers have been forced to choose between two very different switching technologies.
Mechanical and reed relays provide excellent isolation but are comparatively large and slow and eventually experience mechanical and electrical wear.
Solid-state switches are compact and fast but introduce semiconductor leakage, capacitance, nonlinearities, and a fundamentally different off-state electrical path.
Cenfire provides another option.
A microscopic physical contact creates true galvanic isolation when open while MEMS fabrication enables dramatically smaller switching structures and microsecond-scale operation.
The result is a switch designed to provide the isolation engineers want from a relay with the density, speed, and integration needed for next-generation electronic systems.
Hot Switching Should Be Designed In, Not Worked Around
Many systems protect conventional switches by controlling when they are allowed to open or close.
That may require additional circuitry, timing constraints, zero-crossing strategies, snubbers, or operating restrictions intended to reduce stress on the relay.
Those techniques can still be useful, but they also add constraints to system design.
Cenfire’s objective is different.
We want engineers to be able to design around what the system needs to accomplish rather than around the limitations of the switch.
That means developing the contact system to tolerate the electrical events that occur in real applications.
A New Standard for MEMS Hot Switching
For years, hot-switching endurance has been one of the barriers preventing MEMS relays from replacing conventional switching technologies in demanding applications.
Cenfire has attacked that limitation directly through contact engineering, materials science, device architecture, and extensive reliability characterization.
The result is a MEMS switching platform that combines:
- High electrical endurance
- True galvanic isolation
- Less than 10 µs switching
- Ultra-low leakage
- Low open capacitance
- DC-to-GHz operation
- Extremely small form factor
For engineers designing systems where the switch must repeatedly operate under electrical load, those characteristics fundamentally change what is possible.
Cenfire isn’t avoiding hot switching. We are engineering the switch to survive it.