IC Called Lowest-Power ADSL CO Line Driver

Employing what is said to be a breakthrough amplifier architecture that dramatically improves the power efficiency of asymmetrical digital subscriber line (ADSL) drivers, the AD8393 line driver can achieve over 18V of signal on a single 12V supply. The architecture, called Adaptive Linear Power (ALP), is designed to anticipate signal peaks and instantaneously raise the internal supply voltage when peak power is needed. This permits power consumption to be slashed--prior to the new architecture, line driver power dissipation reportedly accounted for over 60% of the total power consumed per port in ADSL central office (CO) applications, limiting overall CO system port density and contributing significantly to system thermal management costs. The AD8393 can drive discrete multi-tone (DMT) signals onto a twisted pair line with a crest factor range of 3.3 to 6.4. The chip permits ±12V performance on a 12V or ±6V supply and boasts of power dissipation for full-rate ADSL of only 575 mW for non-overlapped applications (19.8 dBm line power) and only 624 mW for overlapped applications (20.4 dBm line power). And although optimized for driving a 1:1.2 transformer, the IC's output current is sufficient for driving up to a 1:2 transformer. The AD8393 ADSL CO line driver comes in 28-lead TSSOPs or 32-lead, 5 x 5-mm chip-scale packages. ANALOG DEVICES INC., Wilmington, MA. (781) 937-1428.