HP / Agilent 85024A High-Frequency Probe, 300 kHz to 3 GHz

The HP/Agilent 85024A is an active high-frequency probe engineered for precision in-circuit signal acquisition from 300 kHz to 3 GHz. It delivers minimal circuit loading through 1 MΩ input impedance and sub-0.7 pF input capacitance, enabling accurate measurements on high-density circuits without distorting the signal under test. The probe incorporates a GaAs IC front-end and achieves ±1.25 dB flatness from 300 kHz to 1 GHz, with ±2.5 dB response extending to 3 GHz. Maximum input handling reaches ±1.5 V peak RF and ±50 V DC; optional 10:1 divider operation extends this to ±15 V peak RF and ±200 V DC. Noise remains below 1 mV across 10 Hz to 10 MHz, with harmonic distortion better than –30 dBc at 0.3 V peak input. The 1245 mm probe assembly terminates in Type-N male output and features a retractable grounded metal sleeve for ESD protection. Power is supplied by compatible Agilent instruments or external supply providing +15 V/130 mA and –12.6 V/45 mA.

## Technical Specifications

• **Frequency Range:** 300 kHz to 3 GHz (usable to 100 kHz)
• **Input Impedance:** 1 MΩ (nominal)
• **Input Capacitance:** < 0.7 pF (nominal) at 500 MHz
• **Average Gain:** 0 dB ± 1.25 dB (300 kHz to 1 GHz average)
• **Frequency Response Flatness:** ±1.25 dB (300 kHz to 1 GHz); ±2.5 dB (1 GHz to 3 GHz)
• **Maximum Input Voltage:** ±1.5 V peak RF / ±50 V DC (probe alone); ±15 V peak RF / ±200 V DC (with 10:1 divider)
• **1 dB Compression Point:** 0.3 V peak
• **Average Noise:** < 1 mV (10 Hz to 10 MHz); < 50 dB at 100 MHz; < 25 dB (100 MHz to 3 GHz)
• **Harmonic Distortion:** < –30 dBc (at 0.3 V peak input)
• **Pulse Transition Time:** 200 psec
• **Output Connector:** Type-N male
• **Assembly Length:** 1245 mm (49 in)
• **Net Weight:** 0.255 kg (0.563 lb)

## Key Features

• GaAs IC front-end for high-performance signal acquisition
• High input impedance minimizes circuit loading and distortion
• Ultra-low input capacitance preserves signal integrity on high-frequency nodes
• Retractable grounded metal sleeve protects probe tip and prevents ESD damage
• Dual power-supply capability: instrument-supplied or external +15 V/–12.6 V source

## Typical Applications

• In-circuit probing of RF and microwave circuits
• High-density PCB signal acquisition
• Characterization of active components and transmission lines
• Time-domain and frequency-domain analysis in broadband systems

## Compatibility & Integration

The 85024A connects to network analyzers (HP 8753A, HP 3577A, HP 4195A, HP 71100A), spectrum analyzers (HP 8590A, HP 8562A/B, HP 8568B), frequency counters, and oscilloscopes via Type-N male interface. Power delivery from Agilent instruments or external supply (Agilent 11899A compatible) eliminates cable length constraints on the test bench.