The Keysight N5444A InfiniiMax III probe head is a differential probe accessory designed for high-speed signal acquisition in digital and microwave test environments. It accepts 2.92 mm, 3.5 mm, or SMA coaxial cables and integrates with InfiniiMax III and III+ probe amplifiers to enable single-channel differential measurements on compatible oscilloscopes.
Technical Specifications
• Bandwidth: 28 GHz to 30 GHz
• Rise Time: 14.5 ps (10-90%, probe only with N2803A); 18.8 ps (10-90%, probe only with N2803A)
• Input Impedance: 55 Ω to Vterm (DC to ~1 kHz); 50 Ω to 0.909 × Vterm (>10 kHz)
• Input Voltage Range: 2.5 Vrms
• Input Common Mode Range: ±12 V DC to 250 Hz; ±2.5 V above 250 Hz
• Termination Voltage Range: ±4 V
• Termination Voltage Control: 5 mV minimum step; 80 mA maximum current
• Connector Types: 2.92 mm, 3.5 mm, SMA
– Key Features
• Accepts two coaxial cables for true differential measurements on a single oscilloscope channel
• Termination to adjustable common DC voltage rather than ground—essential for modern signal standards
• Termination voltage controlled internally via oscilloscope or externally through supplied DC jack
• Compatible with all InfiniiMax III and InfiniiMax III+ probe amplifiers (N7000/1/2/3A, N2830/1/2A, N2800/1/2/3A)
• Optional cable extensions available: N5448B flex cables (10″ or 25 cm) and N2823A cables (1 m) in 2.92 mm format
– Typical Applications
• High-speed digital signal integrity measurements
• Differential impedance characterization
• Microwave component testing
• Multi-Gbps serial protocol analysis
– Compatibility & Integration
The N5444A operates with Keysight Infiniium 90000 X-Series and 90000-Q Series oscilloscopes. For use with the 86100D DCA-X sampling oscilloscope, an N5477A Sampling Scope Adapter is required.
