The HP/Agilent 84904L is a programmable step attenuator delivering precision signal level control from DC to 40 GHz with 0 to 11 dB attenuation in 1 dB discrete steps. Built on electromechanical switching with thin-film tantalum nitride attenuators on sapphire substrates, it combines low insertion loss, high repeatability, and fast switching for demanding RF and microwave test applications. The compact form factor—35% smaller than the 8495/7 family—integrates readily into automated test equipment and instrument platforms.
## Technical Specifications
**Frequency Range:** DC to 40 GHz
**Attenuation Range:** 0 to 11 dB in 1 dB steps
**Insertion Loss (at 0 dB):** 0.8 dB + 0.04 dB/GHz (typically <2 dB at 26.5 GHz, 2.4 dB at 40 GHz)
**Attenuation Accuracy:** ±0.3 dB to 26.5 GHz; ±0.4 dB to 40 GHz
**Step-to-Step Accuracy:** ±0.3 dB to 26.5 GHz; ±0.4 dB to 40 GHz
**Maximum SWR:** 1.3 (1 to 12.4 GHz); 1.7 (to 34 GHz); 1.8 (to 40 GHz)
**RF Input Power:** 1 W average / 50 W peak
**Switching Time:** 20 milliseconds maximum (including contact settling)
**Repeatability:** Typically 0.03 dB maximum over 5 million cycles per section
**Connectors:** 2.4 mm female (standard); 2.4 mm/2.92 mm combinations or 2.92 mm female (optional)
**Programming:** 10-pin DIP headers with DC control lines
**Supply Voltage:** 24 Vdc (standard), 5 Vdc or 15 Vdc (optional)
## Key Features
• Electromechanical latching design with permanent magnet retention—survives shocks exceeding 10 Gs
• Solenoid auto-disconnect minimizes power draw and simplifies driver circuits
• Miniature thin-film attenuation cards on sapphire for high stability
• Compact rugged construction enabling straightforward ATE integration
## Typical Applications
• Automated RF and microwave test systems
• Signal level conditioning in broadband measurement chains
• Dynamic range control in receiver and transmitter testing
• Precision attenuation up to 40 GHz millimeter-wave frequencies
## Compatibility & Integration
Programs via DC control lines through 10-pin DIP headers. Compatible with Agilent/Keysight 11713B/C Attenuator/Switch Drivers for GPIB-controlled systems. Ribbon cable (203 mm or 406 mm) and free-wire cabling options available for flexible mounting and connection.
