Keysight (Agilent) 1158A Active Probe, 4 GHz

The Keysight 1158A is a 4 GHz active probe engineered for high-speed signal measurements in confined and geometrically challenging areas of a device under test. Its non-resonant 100 kΩ input impedance with 0.8 pF capacitance, combined with resistive accessories positioned at the probe tip, dampens resonant circuits and delivers flat frequency response across its full bandwidth. The probe achieves 88 ps rise time and supports dynamic ranges up to 5 V peak-to-peak (extending beyond 12 V peak-to-peak for edges exceeding 3 nanoseconds), with ±15 V DC offset capability.

– Technical Specifications

Performance Metrics
• Bandwidth: 4 GHz
• Rise Time: 88 ps
• Propagation Delay: 5.5 ns
• Input Impedance: 100 kΩ, 0.8 pF (non-resonant)
• Maximum Input Voltage: 40 V peak, CAT I
• ESD Tolerance: >5 kV (100pF, 300Ω HBM)

Dynamic Range & Offset
• Peak-to-Peak Range: 5 V (standard); >12 V (for edges >3 ns)
• DC Offset Capability: ±15 V
• Offset Drift: <1.0 mV/°C

Attenuation & Accuracy
• Attenuation: 10:1, ±3% uncalibrated; ±1% calibrated
• Zero Offset Error: <30 mV (uncalibrated), <5 mV (calibrated)
• Offset Accuracy: <3% (uncalibrated), <1% (calibrated)
• Attenuation Drift: 0.1 %/°C
• Noise (referred to input): 3.0 mVrms

Frequency Response Flatness
• 100 kHz to 100 MHz: 0.2 dB
• 100 MHz to 2.5 GHz: 0.4 dB
• 2.5 GHz to 4.0 GHz: 2.0 dB

Power & Environmental
• Supply (via AutoProbe): +12 Vdc @ 3 mA, +5 Vdc @ 35 mA, –5 Vdc @ 37 mA
• Operating Temperature: 0 °C to +55 °C
• Operating Humidity: Up to 95% RH (non-condensing) at +40 °C
• Mass: Approximately 0.69 kg

– Key Features

• Non-resonant input design minimizes measurement anomalies and signal distortion
• Resistive accessories reduce loading effects at the probe tip
• Calibration improves offset accuracy to <5 mV and attenuation accuracy to ±1%
• Wide offset range accommodates biased and AC-coupled signals
• High ESD immunity for field and lab work

– Typical Applications

• High-frequency digital and mixed-signal circuit characterization
• Probing high-speed PCB traces and fine-pitch semiconductor packages
• Signal integrity analysis in GHz-range applications
• Time-domain measurements requiring minimal circuit loading

– Compatibility & Integration

The 1158A operates with Keysight Infiniium Series and InfiniiVision 5000, 6000, and 7000 Series oscilloscopes (excluding 6000 Series 100 MHz models) via the AutoProbe Interface. It accepts a suite of resistive signal pins and ground assemblies optimized for low-loading probing configurations.