The Keysight U1818A is an active differential probe engineered for high-frequency differential signal measurements across 100 kHz to 7 GHz. Designed for R&D and quality assurance teams in RF/microwave, high-speed digital, wireless communications, and aerospace/defense applications, this probe minimizes circuit loading through high differential input impedance while delivering flat frequency response and ultra-low noise performance. The U1818A integrates directly with Keysight’s network, spectrum, and signal source analyzers to enable efficient in-circuit measurements, defect detection, and comprehensive signal characterization.
Technical Specifications
• Bandwidth: 100 kHz to 7 GHz
• Frequency Response: ±1.5 dB flat across the operating band
• Noise Floor: Less than −130 dBm/Hz from 10 MHz to 7 GHz
• Input Impedance: High differential input impedance to minimize loading
• Output: Single-terminated 50-ohm cable for oscilloscope connection
– Key Features
• Compact, lightweight construction
• High differential input impedance reduces circuit perturbation during measurements
• Flat ±1.5 dB response ensures measurement fidelity across the full 7 GHz bandwidth
• Ultra-low noise floor enables detection and analysis of low-amplitude signals
• Powered via probe power port on RF/microwave instruments or external benchtop supply
• Compatible with Keysight probe accessories including temperature extension cables, attenuator kits, DC blocking capacitors, and mechanical positioners
• Supports InfiniiMax differential probe heads (N5380B, N5381B, N2839A, N5425B, N5426A) for multi-frequency and multi-interface measurement configurations
– Typical Applications
• High-frequency differential and single-ended signal measurements in-circuit
• Step response characterization in high-speed digital designs
• Insertion loss measurement between devices
• Phase noise and jitter analysis
• RF troubleshooting and oscillator/PLL testing
• Design validation and qualification testing
– Compatibility & Integration
Direct compatibility with Keysight network analyzers, spectrum analyzers, and signal source analyzers. Works with recommended InfiniiMax probe heads and standard Keysight probe accessories to accommodate diverse measurement geometries and environmental requirements.
