PXIe-2540 350 MHz 8×9 PXI Express RF Matrix Switch Module
The PXIe-2540 is a 350 MHz, 50 Ω PXI Express RF matrix switch module designed for flexible signal routing in automated test and measurement systems. Its 8×9 nonblocking matrix provides 72 crosspoints for connecting eight rows to nine columns.
The nonblocking architecture allows multiple row-to-column connections to exist simultaneously. Isolation relays disconnect unused portions of the matrix to help maintain RF performance, reduce unwanted coupling and provide high open-channel isolation.
The PXIe-2540 is well suited for routing signals among digitizers, function generators, arbitrary waveform generators, RF sources, analyzers and multiple devices under test.
Key Features of the PXIe-2540
- 8×9 nonblocking RF matrix topology
- 72 programmable matrix crosspoints
- DC to 350 MHz characterized bandwidth
- 50 Ω nominal characteristic impedance
- Eight row and nine column connections
- Seventeen front-panel MCX connectors
- 60 VDC or 42.4 Vpk maximum switching voltage
- 0.5 A maximum switching or carry current per channel
- 10 W maximum DC or RF power per channel
- Up to five channels at maximum RF power simultaneously
- Less than 3 dB insertion loss through 350 MHz
- Less than 2.2 VSWR through 350 MHz
- Greater than 75 dB typical open-channel isolation
- Less than -35 dB typical crosstalk
- Less than 6 ns typical propagation delay
- Less than 2 ns typical channel-to-channel skew
- 40-relay simultaneous-drive limit
- 0.25 ms maximum operate and release time
- 100 cycles/s scan rate
- Nonlatching reed relays
- PXI hardware trigger support
- NI-SWITCH and NI Switch Executive compatibility
PXIe-2540 Technical Specifications
| Product Model | PXIe-2540 |
|---|---|
| Part Number | 780587-40 |
| Product Type | PXI Express RF matrix switch module |
| Matrix Topology | 8×9 nonblocking matrix |
| Number of Rows | 8 |
| Number of Columns | 9 |
| Number of Crosspoints | 72 |
| Switch Bandwidth | 350 MHz |
| Characteristic Impedance | 50 Ω nominal |
| Maximum Switching Voltage | 60 VDC or 42.4 Vpk |
| Maximum Switching or Carry Current | 0.5 A per channel |
| Maximum DC Switching or Carry Power | 10 W per channel |
| Maximum RF Power | 10 W per channel in a 50 Ω system |
| Simultaneous Maximum-Power Channels | 5 channels through 350 MHz |
| Initial DC Path Resistance | Less than 2.1 Ω, typical |
| End-of-Life Path Resistance | 3.1 Ω or greater, typical |
| Insertion Loss Through 350 MHz | Less than 3 dB; less than 2.3 dB typical |
| VSWR Through 350 MHz | Less than 2.2; less than 1.6 typical |
| Open-Channel Isolation Through 350 MHz | Greater than 75 dB, typical |
| Crosstalk Through 350 MHz | Less than -35 dB, typical |
| Propagation Delay | Less than 6 ns, typical |
| Channel-to-Channel Skew | Less than 2 ns, typical |
| Simultaneous Relay Drive Limit | 40 relays |
| Maximum Relay Operate Time | 0.25 ms |
| Maximum Relay Release Time | 0.25 ms |
| Scan Rate | 100 cycles/s |
| Mechanical Relay Life | 1 × 109 cycles, typical |
| Electrical Relay Life at 10 V, 100 mA | 1 × 107 cycles, typical |
| Electrical Relay Life at 20 V, 500 mA | 5 × 106 cycles, typical |
| Relay Type | Reed, nonlatching |
| Relay Contact Material | Rhodium |
| Input Trigger Sources | PXI trigger lines 0 through 7 |
| Minimum Input Trigger Pulse Width | 150 ns with digital filtering enabled |
| Output Trigger Destinations | PXI trigger lines 0 through 7 |
| Default Output Trigger Pulse Width | 2 µs typical |
| Front-Panel Connectors | 17 MCX female connectors |
| Bus Interface | PXI Express |
| PXI Express Power Requirement | 10 W at 12 V and 2.5 W at 3.3 V |
| Module Format | 3U, one-slot PXI Express module |
| Dimensions | 21.6 cm × 2.0 cm × 13.0 cm |
| Weight | 380 g |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -20°C to 70°C |
| Relative Humidity | 5% to 85%, noncondensing |
| Software Support | NI-SWITCH and NI Switch Executive |
PXIe-2540 Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| PXIe-2540 | 780587-40 | 350 MHz, 8×9 PXI Express RF matrix switch module |
| MCX-to-MCX Cable | 188374-0R15 | 0.15 m MCX plug-to-MCX plug coaxial cable |
| MCX-to-MCX Cable | 188374-0R3 | 0.3 m MCX plug-to-MCX plug coaxial cable |
| MCX-to-MCX Cable | 188374-01 | 1 m MCX plug-to-MCX plug coaxial cable |
| MCX-to-BNC Cable | 188375-0R3 | 0.3 m MCX plug-to-BNC plug coaxial cable |
| MCX-to-BNC Cable | 188375-01 | 1 m MCX plug-to-BNC plug coaxial cable |
| MCX-to-SMB Cable | 188376-0R3 | 0.3 m MCX plug-to-SMB plug coaxial cable |
| MCX-to-SMB Cable | 188376-01 | 1 m MCX plug-to-SMB plug coaxial cable |
| MCX-to-SMA Cable | 188377-01 | 1 m MCX plug-to-SMA plug coaxial cable |
The PXIe-2540 provides seventeen front-panel MCX connectors: eight row connections and nine column connections. Select cable type and length according to the connector used by the source, instrument, fixture or device under test.
8×9 RF Matrix Architecture
The PXIe-2540 contains eight matrix rows and nine matrix columns. A programmable relay crosspoint is located at every row-and-column intersection, producing 72 possible connections.
Software can connect any row to any column. Multiple crosspoints can be closed at the same time, allowing signals to be distributed or routed among several instruments and DUT connections.
This architecture is more flexible than a fixed multiplexer because the test program is not limited to selecting only one channel for a shared common connection.
72 Programmable Crosspoints
Each of the 72 crosspoints represents a possible electrical connection between one row and one column. NI-SWITCH controls these crosspoints according to channel names and route commands.
For example, row R0 can be connected to column C2 while row R5 is connected to column C7. Additional connections can be established when they do not violate the electrical or simultaneous-drive limitations.
The large number of possible routes allows one matrix configuration to support several DUT types and test sequences.
Nonblocking Matrix Design
The nonblocking architecture allows any available row-to-column connection to be established without requiring a previously created route to be disconnected solely because of the matrix structure.
This provides greater freedom when routing several instruments to several DUT connections. The actual route plan must still avoid electrically conflicting sources and remain within voltage, current and power ratings.
Nonblocking operation is especially useful in automated test systems whose routing requirements change between test steps or product variants.
Simultaneous Matrix Connections
Multiple crosspoints can be active at the same time. This allows the module to distribute one source to several measurement points or connect several independent instruments and DUT channels.
The module has a simultaneous-drive limit of 40 relays. Route configurations requiring more closed relays must be redesigned or distributed across additional switching modules.
Before connecting one row to several columns, confirm that the source can drive all connected loads and that the connection will not create an unintended parallel path.
Isolation Relay Architecture
The PXIe-2540 includes isolation relays that disconnect unused portions of the matrix. This helps reduce the number of unused traces attached to the active RF path.
Disconnecting unused matrix sections improves RF isolation and limits the parasitic capacitance that can otherwise degrade bandwidth, VSWR and insertion loss.
Isolation relays are managed through the module’s routing architecture and should be considered when designing custom route sequences.
DC to 350 MHz Signal Routing
The PXIe-2540 is characterized for RF operation through 350 MHz. It can also route DC and lower-frequency analog signals within its voltage, current and power limitations.
The bandwidth supports function generators, arbitrary waveform generators, digitizers, oscilloscopes and other instruments operating in the low-to-moderate RF frequency range.
System bandwidth depends on the matrix route, cable length, source impedance, load impedance and external fixture design.
50 Ω Characteristic Impedance
The module has a nominal characteristic impedance of 50 Ω. This matches many RF generators, digitizers, oscilloscopes, analyzers and coaxial test systems.
Use 50 Ω cables, adapters and terminations throughout the signal path. Impedance mismatch can increase reflections, degrade VSWR and change the signal level delivered to the DUT.
Insertion Loss Performance
Insertion loss measures how much signal power is lost through a selected row-to-column route. Through 350 MHz, insertion loss is specified below 3 dB, with a typical value below 2.3 dB.
A matrix route passes through multiple internal switching elements, so its insertion loss is normally higher than that of a simple SPDT relay.
External cables, adapters and fixtures introduce additional loss. Apply path-specific correction or calibration when accurate amplitude measurements are required.
VSWR Performance
Voltage standing wave ratio indicates the impedance match of the active signal path. The PXIe-2540 has specified VSWR below 2.2 through 350 MHz, with a typical value below 1.6.
System-level VSWR also depends on the connected instruments, cables, terminations and DUT. Use properly rated 50 Ω components and keep RF cables as short as practical.
Open-Channel Isolation
Typical open-channel isolation is greater than 75 dB through 350 MHz. High isolation helps prevent unwanted signals from passing through an open matrix crosspoint.
Isolation relays improve performance by disconnecting unused matrix sections. External cable routing and fixture shielding also affect total isolation.
Matrix Crosstalk
Typical crosstalk is below -35 dB through 350 MHz. Crosstalk measures unwanted signal coupling between separate active or inactive matrix paths.
High-power signals should be separated from sensitive measurement paths when possible. Shielded coaxial cables and careful fixture grounding can reduce external coupling.
Propagation Delay
The typical propagation delay through a matrix route is less than 6 ns. This delay should be included when timing alignment between switched and direct paths is important.
The complete system delay includes the matrix, external cables, adapters and device-under-test fixture.
Channel-to-Channel Skew
Typical channel-to-channel skew is below 2 ns. Skew represents the difference in propagation delay among different matrix routes.
Use equal-length external cables and characterize each important route when precise timing consistency is required.
10 W RF Power Capability
The PXIe-2540 supports up to 10 W per channel in a 50 Ω RF system. The module can carry maximum RF power through as many as five channels simultaneously through 350 MHz.
Maximum permissible power decreases as frequency and the number of simultaneously loaded channels increase. The official RF power-derating curves should be checked for every high-power route configuration.
Average and peak power should both be evaluated for pulsed or modulated signals.
60 V and 0.5 A Electrical Ratings
The maximum switching voltage is 60 VDC or 42.4 Vpk. Maximum switching or carry current is 0.5 A per channel.
The maximum DC switching or carry power is 10 W per channel. Voltage, current and power limits apply simultaneously.
The module should not be connected directly to circuits that exceed any of these ratings.
Switching Active RF Signals
NI recommends avoiding active RF switching whenever possible. A relay path is momentarily unterminated while a crosspoint opens or closes.
This temporary mismatch can reflect RF energy toward the source. Some generators and amplifiers may be damaged when their outputs are not properly terminated.
Reduce or disable source power before changing routes when required by the source documentation.
Fast Reed Relay Switching
The PXIe-2540 uses nonlatching reed relays with a maximum operate time of 0.25 ms and maximum release time of 0.25 ms.
Fast relay response supports automated routing and a scan rate of up to 100 cycles per second. Actual throughput also depends on measurement aperture, signal settling and software execution.
Nonlatching Relay Operation
The relays are nonlatching, meaning coil power is required to maintain their activated state. When the module loses power, the relays return to their default position.
This behavior provides a predictable power-off condition. The application should still initialize all routes before applying signals to the test system.
Reed Relay Life
The typical mechanical relay life is up to one billion operations. Electrical life depends on the switched voltage, current and load characteristics.
At 10 V and 100 mA with a suitable resistive load, typical electrical life is approximately ten million cycles. At 20 V and 500 mA, typical electrical life is approximately five million cycles.
Capacitive and inductive loads can substantially reduce relay life unless appropriate protection is used.
Capacitive and Inductive Load Protection
Reed relays are sensitive to high inrush current from capacitive loads and high flyback voltage from inductive loads.
Use current limiting, series resistance, flyback diodes, snubbers or other suitable protection according to the circuit. Protection should be selected without degrading the required RF performance.
PXI Hardware Triggering
The PXIe-2540 accepts input triggers from PXI trigger lines 0 through 7. The minimum input-trigger pulse width is 150 ns when digital filtering is enabled.
Output triggers can be routed to PXI trigger lines 0 through 7, with a typical default pulse width of 2 µs.
Hardware triggering allows switching operations to be synchronized with digitizers, generators, data acquisition modules and other PXI Express instruments.
Typical PXIe-2540 Applications
- Automated RF signal routing
- Digitizer input selection
- Function-generator output routing
- Oscilloscope channel selection
- Multiple-instrument test systems
- Multiple-DUT production testing
- RF component characterization
- Communications equipment validation
- Design verification testing
- Semiconductor device testing
- Research and laboratory automation
- Custom nonblocking switching networks
Digitizer and Oscilloscope Routing
The PXIe-2540 can connect several DUT outputs to one or more digitizer and oscilloscope inputs. Software changes the active crosspoints according to the current measurement step.
Route-specific insertion loss and propagation delay should be included when amplitude and timing accuracy are important.
Function Generator Routing
Function generators and arbitrary waveform generators can be connected to matrix rows, while DUT stimulus points are connected to columns.
The nonblocking architecture allows several independent generators to stimulate different DUT connections simultaneously, provided conflicting sources are not connected together.
Multiple-Instrument Test Systems
The matrix can route several instruments to several test points without manual cable changes. This improves instrument utilization and allows one fixture to support multiple test configurations.
NI Switch Executive can define logical route names corresponding to each instrument and DUT connection.
Multiple-DUT Production Testing
Production systems can share signal sources and measurement instruments among several DUT positions. Software selects the required matrix connections for each test operation.
Fast reed relays and programmable routes support repeated high-volume switching, while isolation relays help maintain RF performance.
RF Component Characterization
The PXIe-2540 can route sources and analyzers to filters, amplifiers, attenuators and other RF components. Different test paths can be selected without manually reconnecting coaxial cables.
Calibration should include the matrix path and external cable assembly to remove fixture-related loss and delay from the measurement.
NI-SWITCH Software Support
The PXIe-2540 is controlled through the NI-SWITCH instrument driver. NI-SWITCH provides functions for initializing the module, connecting and disconnecting matrix crosspoints, creating scan lists and configuring triggers.
The driver supports LabVIEW, LabWindows/CVI and compatible text-based programming environments. It can also be integrated into NI TestStand automated test sequences.
NI Switch Executive Integration
NI Switch Executive allows engineers to define named routes and route groups instead of controlling individual row-and-column crosspoints directly in application code.
Meaningful route names make a 72-crosspoint matrix easier to configure, understand and maintain. Route validation can help prevent conflicting sources or unintended signal paths.
PXI Express Chassis Integration
The PXIe-2540 occupies one slot in a compatible PXI Express chassis. It can operate alongside digitizers, waveform generators, oscilloscopes and other NI PXI and PXI Express modules.
Before installation, verify slot compatibility, controller communication, chassis cooling, MCX cable clearance and the installed NI-SWITCH version.
PXIe-2540 Troubleshooting
The PXIe-2540 is not detected in NI MAX
Confirm that the module is fully installed in a compatible PXI Express slot. Check chassis power, controller communication and NI-SWITCH installation, then restart NI Measurement & Automation Explorer.
A row does not connect to the selected column
Verify the row and column names used in the route command. Inspect the MCX cables, connectors and external fixture wiring, then test the crosspoint with a simple known signal.
A route conflicts with another connection
Review the complete matrix configuration and check for sources connected together through a shared row or column. Use NI Switch Executive route validation to identify conflicting paths.
Insertion loss is higher than expected
Inspect the MCX cables, adapters and connectors. Confirm that all external components are rated for 350 MHz and include cable and fixture losses in the path calculation.
VSWR is too high
Verify that the complete signal path uses 50 Ω components. Check connector condition, cable damage, source impedance, load impedance and unused-port termination.
Isolation is lower than expected
Confirm that unused matrix sections are disconnected and inspect external cables for coupling. Improve cable separation, shielding and fixture grounding where necessary.
Crosstalk is visible between routes
Separate high-amplitude and low-level signal cables. Check whether external instruments or DUT connections create a coupling path outside the matrix.
The module cannot close all requested crosspoints
Count the number of simultaneously driven relays. The PXIe-2540 has a 40-relay simultaneous-drive limit, so very large route configurations may require multiple modules.
A reed relay becomes unreliable
Check whether capacitive inrush current or inductive flyback exceeded the relay rating. Inspect the external circuit and add appropriate protection before replacing or servicing the module.
The scan rate is lower than expected
Review relay settling, measurement aperture, device stabilization, trigger configuration and software execution. The 100 cycles/s rating does not include every delay in a complete test sequence.
PXIe-2540 Comparison with Similar RF Switch Modules
| Model | Primary Configuration | Best Suited For |
|---|---|---|
| PXI-2540 | 8×9 RF matrix with PXI interface | Maintaining compatible legacy PXI matrix systems |
| PXIe-2540 | 350 MHz, 8×9 PXI Express RF matrix | Flexible nonblocking routing with 72 crosspoints |
| PXIe-2541 | RF matrix with additional routing architecture | Applications requiring alternative matrix connectivity |
| PXIe-2542 | Higher-frequency PXI Express RF switch | Applications requiring multi-gigahertz signal routing |
| PXIe-2543 | 6.6 GHz PXI Express RF multiplexer | High-frequency multiplexer applications |
PXIe-2540 vs PXI-2540
Both models provide an 8×9, 50 Ω RF matrix. The PXIe-2540 uses the PXI Express interface and supports up to five simultaneous maximum-power channels, while the legacy PXI version has different bus and loading characteristics.
Choose the PXIe-2540 for a PXI Express installation. Choose the PXI-2540 when maintaining an existing compatible PXI system.
PXIe-2540 vs PXIe-2543
The PXIe-2540 provides a flexible 8×9 nonblocking matrix through 350 MHz. The PXIe-2543 provides much higher RF frequency coverage but uses a multiplexer-oriented topology.
Choose the PXIe-2540 when flexible many-to-many routing is more important than multi-gigahertz bandwidth. Choose the PXIe-2543 when the application requires higher-frequency multiplexer switching.
PXIe-2540 vs PXI-2547
The PXIe-2540 provides an 8×9 matrix with 72 crosspoints through 350 MHz. The PXI-2547 provides a fixed 8×1 multiplexer with frequency coverage through 2.7 GHz.
Select the PXIe-2540 for flexible matrix routing or the PXI-2547 when higher bandwidth and a fixed eight-channel multiplexer are required.
Recommended Related Products
- PXI-2540 8×9 RF Matrix Switch Module
- PXIe-2541 RF Matrix Switch Module
- PXIe-2542 High-Frequency RF Switch Module
- PXIe-2543 6.6 GHz RF Multiplexer Module
- PXI-2547 2.7 GHz 8×1 RF Multiplexer Module
- View More NI PXI and PXI Express Modules
Selecting the Right PXI RF Switch
Choose the PXIe-2540 when the application requires a nonblocking 8×9 matrix, 72 programmable crosspoints, 50 Ω impedance and signal routing through 350 MHz.
Select a fixed multiplexer when several channels only need to share one common instrument. Choose a higher-frequency PXI Express RF module when operation above 350 MHz is required.
Why Choose the PXIe-2540?
- Provides an 8×9 nonblocking RF matrix
- Offers 72 programmable crosspoints
- Supports multiple simultaneous routes
- Routes signals from DC through 350 MHz
- Maintains 50 Ω characteristic impedance
- Uses isolation relays to disconnect unused matrix sections
- Provides greater than 75 dB typical open-channel isolation
- Handles up to 10 W per RF channel
- Uses fast, long-life reed relays
- Provides seventeen MCX front-panel connectors
- Supports PXI hardware triggering
- Integrates with NI-SWITCH and NI Switch Executive
Frequently Asked Questions
What is the PXIe-2540?
The PXIe-2540 is a 350 MHz, 50 Ω PXI Express RF matrix switch module providing eight rows, nine columns and 72 crosspoints.
What is the PXIe-2540 topology?
It uses an 8×9 nonblocking matrix topology that allows multiple row-to-column connections to operate simultaneously.
How many crosspoints does the PXIe-2540 provide?
The module provides 72 programmable crosspoints.
What is the PXIe-2540 bandwidth?
The module is characterized for RF signal routing through 350 MHz.
What is the characteristic impedance?
The PXIe-2540 has a nominal characteristic impedance of 50 Ω.
What is the maximum switching voltage?
The maximum switching voltage is 60 VDC or 42.4 Vpk.
What is the maximum switching current?
The maximum switching or carry current is 0.5 A per channel.
What is the maximum RF power?
The maximum RF power is 10 W per channel in a 50 Ω system, subject to frequency and simultaneous-channel derating.
How many maximum-power channels can operate simultaneously?
Up to five channels can carry maximum RF power simultaneously through 350 MHz under the specified conditions.
What connectors does the PXIe-2540 use?
The front panel provides seventeen MCX female connectors: eight rows and nine columns.
Does the PXIe-2540 use latching relays?
No. It uses nonlatching reed relays with rhodium contacts.
Which software controls the PXIe-2540?
The module is controlled through NI-SWITCH and can be integrated into named-route applications using NI Switch Executive.
What is the PXIe-2540 part number?
The standard NI part number for the PXIe-2540 is 780587-40.
Request a Quote for the PXIe-2540
Contact us for current availability, lead time and project pricing for the PXIe-2540 350 MHz 8×9 PXI Express RF Matrix Switch Module. We can also help identify compatible MCX cables, adapters, PXI Express chassis and related NI RF switch modules for your automated test system.
