Amplifier Research 25S1G4A

The Amplifier Research 25S1G4A is a solid-state, air-cooled broadband amplifier designed for laboratory and bench applications requiring instantaneous bandwidth across 0.8 GHz to 4.2 GHz. This self-contained unit delivers a minimum of 25 watts of RF power with 44 dB minimum gain and ±1.5 dB typical flatness. The amplifier accepts a maximum input of 1.0 milliwatt for rated output and provides continuous gain adjustment over a 10 dB minimum range with 4096 remote steps.

Technical Specifications

• Frequency Range: 0.8 GHz to 4.2 GHz instantaneous


• Rated Power Output: 25 watts minimum


• Input for Rated Output: 1.0 mW maximum


• Power @ 3 dB Compression: 32 W nominal, 25 W minimum


• Power @ 1 dB Compression: 27 W nominal, 20 W minimum


• Gain (maximum setting): 44 dB minimum


• Gain Adjustment Range: 10 dB minimum with 4096 remote steps


• Flatness: ±1.5 dB typical, ±2.0 dB maximum


• Input Impedance: 50 ohms; VSWR 2.0:1 maximum


• Output Impedance: 50 ohms nominal


• Third Order Intercept (IP3): Determined using two tones spaced 1 MHz apart, typical for WCDMA systems


• Spurious: -73 dBc typical


• Modulation: Faithfully reproduces AM, FM, and pulse modulation


• Power Supply: 90–132 VAC or 180–264 VAC, 50/60 Hz single phase, 340 W maximum

Key Features

• RF input leveling circuit protects first-stage amplifiers against overdrive when input exceeds 0 dBm


• Over-temperature protection removes DC voltage to amplifier stages upon cooling system failure


• 100% mismatch tolerance - operates without damage or oscillation under any load impedance condition


• Digital display indicates operational status and fault conditions


• Front panel gain control for local operation


• Removable from cabinet for benchtop or equipment rack mounting

Interfaces and Control

• IEEE-488 (GPIB) control via 24-pin female connector


• RS-232 remote control via 9-pin Subminiature D female connector


• Local front panel adjustment and monitoring