The HP/Agilent 44476B is a microwave relay driver module that controls Agilent 876XX series coaxial switches within automated test systems. It provides break-before-make switching via latching solenoids and internal form C relays, enabling signal routing across multi-port switch configurations without continuous coil voltage. The module integrates two sets of mounting panels for user-supplied coaxial switches and supplies internal +5 VDC to drive compatible switch elements. When paired with 876XX switches, the 44476B extends three-port automated switching capability to 26.5 GHz, making it suitable for high-frequency RF and microwave test applications requiring repeatable, complex signal path configurations.
Technical Specifications
• Product Type: Microwave relay driver module
• Manufacturer: HP/Agilent/Keysight
• Model: 44476B
• Switch Compatibility: Two Agilent 876XX series coaxial switches (3-, 4-, or 5-port configurations)
• Frequency Extension: Up to 26.5 GHz with compatible 876XX switches
• Coil Voltage Support: +5 VDC (Option 011)
• Internal Power Supply: +5 VDC for microwave switch operation
• Control Architecture: Internal form C relays (K901, K902, K903)
• Switching Type: Break-before-make with latching solenoids
• Panel Cutouts: Two apertures, 53.8 × 9.6 mm each, for coaxial switch mounting
– Key Features
• Latching solenoid design eliminates continuous coil voltage requirement after switching state is set
• Internal +5 VDC supply eliminates external power dependencies for switch operation
• Break-before-make relay logic ensures signal isolation during transitions
• Two-panel configuration supports dual-switch matrices
• HP-IB integration for automated control within test systems
– Typical Applications
• Multi-port RF signal routing in microwave test systems
• Automated frequency-dependent switch matrix control
• Complex signal path reconfiguration in high-frequency measurement setups
– Compatibility & Integration
• Primary Mainframe: HP 3488A Switch/Control Unit
• Switch Series: Agilent 876XX (8763B, 8762x, and related models)
• Connector Interface: SMA connectors on compatible 876XX switches (module itself has no RF connectors)
• Note: Coaxial relays must be ordered separately from switches
