Electronic Design

Adaptive linear Amp Cuts Line Driver's Dissipation

Thanks to an adaptive linear-power (ALP) amplifier architecture, Analog Devices' single-supply ADSL line driver slashes power dissipation and dramatically improves efficiency over competing solutions.

The AD8393 is the first implementation of ALP. It drives discrete multitone (DMT) signals onto a twisted pair with a crest factor (peak to rms ratio) range of 3.3 to 6.4. For non-overlapped full-rate ADSL applications, full-power line-driver dissipation is only 575 mW (19.8-dBm line power), or 624 mW (20.4 dBm) for overlapped applications. While optimized for driving a 1:1.2 transformer, the device has sufficient output current to drive a 1:2 transformer ratio.

Also, the AD8393 achieves an 18-V signal from a single 12-V supply. "This enables system designers to eliminate as many as three analog supply voltages in class-G line drivers," says John Pierdomenico, senior design engineer at ADI. "Compared with competing class-AB line drivers, the ALP architecture can in-crease central-office power efficiency by about 22%, enabling increased port density."

Available in 28-lead TSSOPs and 32-lead chip-scale packaging (CSP), the AD8393 is sampling now. Production is slated for next quarter. In 1000-piece quantities, it costs $3.95.

Analog Devices Inc., (781) 937-1428; www.analog.com.

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