ISL55210-ABEVAL1Z

This relatively simple board is intended to provide a quick means to test the performance of the active balun configuration using the ISL55210 wideband, fully differential amplifier (FDA). While all wideband, voltage feedback (VFA), fully differential amplifiers can perform a single-ended input to differential output operation, the frequency span for acceptable input match (or low return loss) is greatly enhanced by the >1.5GHz common mode loop bandwidth internal to the ISL55210.

Quickly evaluate performance:

• AC coupled single-ended input with a wideband "active" impedance match
• Convert to differential in the ISL55210 to give a very broadband balun operation
• Extremely low input referred noise for a matched input using the much lower resistor setting of the active match
• Exceptional OIP3 for 115mW device. At a doubly terminated 50Ω load, OIP3 >40dBm through 200MHz

This board offers considerable flexibility in the input match and gain by simply changing four resistor values. It also offers several possible output interfaces to either get single-ended or run differential output. As delivered, the default configuration delivers:

• 50Ω input impedance with >34dB return loss from 1MHz to 400MHz
• Single-ended input to single-ended measurement output with 10.2dB gain and -1dB span from 3MHz to 800MHz
• Input noise figure <7.5dB referenced to a 50Ω source.