Agilent/Keysight N2831A

The Keysight N2831A is an 8 GHz probe amplifier in the InfiniiMax III+ Series, purpose-built for differential and single-ended signal integrity measurements. This amplifier expands measurement capabilities by enabling analysis of differential, single-ended, and common mode signal components from a single probe connection. InfiniiMode technology allows switching between measurement modes - differential (A–B), single-ended A (A–ground), single-ended B (B–ground), and common mode ((A+B)/2–ground) - without repositioning the probe tip.

Technical Specifications

• Bandwidth: 8 GHz (–3 dB)


• Rise time: 54.25 psec (10–90%)


• DC attenuation ratio: 10:1 / 5:1 selectable


• Input voltage range: 2.5 Vpp (5:1 mode) or 5 Vpp (10:1 mode)


• Input common mode range: ±7 VDC to 100 Hz; ±1.25 V (5:1) or ±2.5 V (10:1) above 100 Hz


• DC offset range: ±16 V (single-ended probing)


• Differential input resistance (DC): 100 kΩ ± 2%


• Single-ended input resistance (DC): 50 kΩ ± 2%


• Differential input resistance (>10 kHz): 1 kΩ


• Single-ended input resistance (>10 kHz): 500 Ω


• Differential input capacitance: 32 fF (with ZIF probe head)


• Single-ended input capacitance: 44 fF (with ZIF probe head)

Key Features

• InfiniiMode measurement technology enables flexible signal analysis modes from one probe connection


• Compatible with the complete InfiniiMax III probe head family, including QuickTip, ZIF, 2.92 mm/3.5 mm/SMA, solder-in, and browser configurations


• AutoProbe interface provides automatic probe detection and power management


• Not compatible with InfiniiMax I or II probe heads

Typical Applications Differential signal characterization, single-ended and common mode analysis, multi-layer PCB probing, high-speed serial link validation, and complex signal decomposition in demanding measurement environments.

Compatibility & Integration The N2831A integrates with Infiniium 90000X/Q Series oscilloscopes (20 GHz models) and works exclusively with InfiniiMax III probe heads. This is a discontinued product.