Model Explanation

PXI: PXI bus standard (PCI eXtensions for Instrumentation)

2559: Product serial number, specifically referring to the dual SPDT, built-in 75Ω termination, 75Ω RF relay module

Full name: PXI-2559 / 778572-59 → 2.5 GHz 75Ω Dual SPDT Relay Module (Terminated)

Topology alias: NISWITCH_TOPOLOGY_2559_TERMINATED_2_SPDTNI Technical Specifications

Radio frequency performance

Bandwidth: DC～2.5 GHz

Characteristic impedance: 75 Ω (suitable for video / CATV)

Terminal matching: Each channel has an internal 75Ω terminal (NO/NC port) NI

Insertion loss: ≤1.7 dB @ 2.5 GHz

VSWR: ≤1.5:1 @ 2.5 GHz

Channel isolation: ≥60 dB @ 2.5 GHz

Switching and electrical

Topology: 2 independent SPDT (Dual SPDT), each channel has 1COM, 1NO, 1NC, with 75Ω terminal built-in NI

Relay type: RF reed relay (latching, lock-in type)

Maximum switching voltage: 30 V

Maximum channel current: 0.5 A (per channel)

Maximum RF power: 3 W (25°C); Built-in terminal power 1.5 W (25°C), temperature rating reduced NI

Relay lifespan: ≥10⁶ times (typical value)

Control interface: PXI bus (NI- SWITCH driver)

Physical and environmental

Size: Standard PXI 3U single slot

Weight: Approximately 0.4 kg

Connectors: Front panel 6×BNC (2×COM, 2×NO, 2×NC), all 75Ω

Operating temperature: 0～55°C

Storage temperature: –40～70°C

Interface and communication configuration

Front panel interface

CH1, CH2: Each channel contains COM (common terminal), NO (normally open, built-in 75Ω terminal), NC (normally closed, built-in 75Ω terminal), a total of 6 BNC, 75Ω NI

Key features: NO/NC ports have permanently built-in 75Ω terminals, no external load required, reducing reflections

Backplane and control

PXI backplane: 3U single slot, compatible with PXI-1/PXIe mixed slots

Power supply: PXI backplane ±15 V, 5 V power supply (typical power consumption 3.5 W)

Trigger: Supports PXI TTL0～TTL4 hardware trigger, software immediate trigger

Driver: NI- SWITCH, supports LabVIEW, TestStand, CVI

Core functions

2 independent SPDT switching + built-in terminal: Each COM can be switched to NO or NC, NO/NC has a 75Ω terminal built-in, no external load required, completely eliminating reflections NI

75Ω wideband signal transmission: DC～2.5 GHz, suitable for video, CATV, RF component testing

Simplifies system design: Built-in terminal, reduces external loads and wiring, improves reliability

Relay lifespan tracking: Board-mounted counter, predictive maintenance, reduces downtime

PXI plug-and-play: Standard driver, quick integration into automated test systems Applicable scenarios

Video / Cable Television (CATV) signal switching: Multi-channel video routing, distribution and switching, without additional terminals required

RF component testing: Input/output switching for amplifiers, filters, attenuators, suppression of reflections, and improvement of test accuracy

Aerospace / Defense: Multi-channel RF signal routing, testing of satellite communication equipment

Semiconductor testing: Signal path configuration for RF chips, transceivers

Industrial ATE: Production electronic product RF / video function testing, simplification of switch matrix design

User and maintenance instructions

Installation and configuration

Insert the PXI 3U single slot and fix the panel

Install the NI-SWITCH driver, identify the hardware, and configure the topology as Terminated 2-SPDTNI

Connect BNC cables, avoid excessive force bending; no external terminals (NO/NC are already built-in) NI

Key operation points

RF power limitation: When the temperature is 25°C, the single-channel RF power ≤ 3 W, the built-in terminal ≤ 1.5 W, and the temperature rise reduction is applied NI

Avoid static electricity: Ground before operation, add an anti-static cap to the port, and prevent static electricity from damaging the RF relay

Trigger mode: Software immediate trigger (low speed) or PXI TTL hardware trigger (high-speed synchronization)

Independent control: 2 SPDT can be independently controlled, and they do not interfere with each other

Maintenance and calibration

Life monitoring: Read the number of times the relay is closed through NI-SWITCH, and replace it when it reaches 10⁶ times

Regular calibration: Calibrate insertion loss, VSWR, and isolation every year to ensure test accuracy

Environmental requirements: Operating temperature 0～55°C, humidity 10%～90% (no condensation)

Storage: -40～70°C, dry and dust-free, clean the connectors before long-term storage