Lecroy DA1855A High-performance Differential Amplifier, 100MHz

The LeCroy DA1855A is a differential amplifier delivering DC to 100 MHz bandwidth with selectable gain (X1 or X10) and exceptional common mode rejection. It converts differential signals into single-ended outputs for oscilloscopes, digitizers, and spectrum analyzers, offering overdrive recovery and minimal distortion across high-speed measurement applications.

Technical Specifications

• Bandwidth: DC to 100 MHz with selectable limiting filters (20 MHz, 1 MHz, 100 kHz)


• Gain: X1 or X10 (selectable)


• Input Coupling: AC, DC, or Off (Precharge) on '+' input; AC, DC, Off, or VCOMP on '−' input


• Input Impedance: 1 MΩ or 100 MΩ (÷1 attenuator); 1 MΩ (÷10 attenuator)


• Input Capacitance: 20 pF


• Common Mode Rejection Ratio: 100,000:1


• Overdrive Recovery: Settles within 100 mV (referred to input) from 400 V input within 100 ns (with ÷100 probe)


• Rise Time: < 3.5 ns (typical)


• Input Leakage Current: < 10 pA (0 °C to 45 °C)


• Output: Single-ended, ground-referenced, ±500 mV limit


• Output Impedance: 50 Ω (intended load)


• Output Connector: BNC

Key Features

• Precision Voltage Generator (PVG): ±15.5 V range (±10 V in Differential Offset mode), 100 µV resolution, 0.05% accuracy + 500 µV (15 °C to 45 °C)


• PVG Temperature Stability: < 5 ppm/°C of full scale; oven-stabilized buried zener design


• Comparator Mode: PVG selectable as inverting input for differential comparator operation on small signals riding large AC/DC components


• True Differential Offset Mode: ±50,000 divisions with 5½ digit resolution


• Auto-Zero Function: Sets output to 0 V when selected; periodically adjusts DC balance on gain setting changes


• ProBus Interface: Full remote control and automated settings from compatible Teledyne LeCroy oscilloscopes


• External PVG Output: Available via rear panel connector

Typical Applications High-speed data acquisition, signal conditioning for differential measurements, precision offset control in comparator circuits, and low-distortion signal processing across test and measurement platforms.

Compatibility & Integration Integrates directly with Teledyne LeCroy oscilloscopes via ProBus interface for unified instrument control. Rear panel connectors support external access to PVG output.