Intersil claims lowest power, dual port, Class G line driver

November 02, 2012 // By Paul Buckley
Intersil Corporation has extended the company’s 20-year history of providing leading-edge products to the central office DSLAM market with the introduction of the ISL1561, the most power-efficient Class G line driver.

Designed for existing and emerging xDSL central office reference designs with  improvements over Class H solutions, the ISL1561 provides backward compatibility to existing +14 V systems. The company’s industry leading design supports another 10% power savings in emerging +12 V single supply systems.

Each of the two ports is internally configured for a fixed 11.6 V/V gain using a specific external build out resistor and a cross-coupled feedback, providing active output impedance with reduced losses. A three-pin serial interface allows each port to be separately tuned to the minimum required quiescent current for the intended signal standard. Two external supply voltage boost caps provide a brief peak in the total output stage voltage to supply the peak line voltages using a control signal from the AFE.

The ISL1561 features a nominal quiescent current to support full line power for ADSL2+ is only 8 mA/port; VDSL2+ 8b is 10 mA/port; and VDSL2+ 17a is 12 mA/port.

For the most demanding 8b profile, total quiescent power to deliver 19.5 dBm to the line is reduced from >900 mW/port to <620 mW/port.  Signal peaks maintains a signal linearity comparable to much higher power +24 V class AB solutions.

Availability and Pricing

The ISL1561 is available now in compact 24-lead QFN packages, with prices starting at $2.57 each in 1,000-unit quantities.

More information about the ISL1561 Class G line driver at