Agilent/Keysight 44423A

The Agilent/Keysight 44423A is a 20-channel FET multiplexer that routes signals in automated test systems and precision measurement applications. Each of its 20 channels contains three relays

High, Low, and Guard lines - organized into two groups of 10. The multiplexer supports flexible switching modes: one channel per decade closure, random channel selection, or incremental stepping between programmable limits.

Simultaneous closure of two channels (one per decade) enables four-terminal resistance measurements. Its low thermal offset characteristics make it ideal for precision transducer and temperature-sensor measurements where signal integrity and measurement accuracy are critical.

Technical Specifications

• Channel Configuration: 20 channels organized into two groups of 10


• Relay Configuration: Three relays per channel (High, Low, Guard lines)


• Switching Modes: Single channel per decade; random or incremental channel closure between programmable limits


• Simultaneous Operation: Two channels closeable at once (one per decade), enabling four-terminal measurements


• Thermal Performance: Low thermal offset for precision low-level measurements


• Physical: 15 × 8 × 3 inches, 2 lbs

Key Features

• Multi-mode switching for flexible signal routing in automated test environments


• Guard line capability on each channel for noise rejection and signal integrity


• Programmable channel sequencing with random and incremental stepping options


• Four-terminal measurement support for accurate impedance and resistance characterization

Typical Applications

• Transducer and sensor signal multiplexing


• Temperature measurement systems requiring low thermal offsets


• Precision resistance and impedance measurement via four-terminal configuration


• Automated test systems with multi-channel signal routing requirements

Compatibility & Integration The 44423A is designed as an option for the 3497A Data Acquisition/Switch Unit, integrating directly into mainframe-based test systems.